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2002 GM LPG Van Service Manual

1. OP ace sag We ee eS ees a ee et A E a d J Powertrain 1 1 Alternative Fuel i Control i Engine Control 1 ECT Sensor IAT Sensor 5 Volt 5Volt 1 Module 1 ECT Sensor IAT Sensor 5Volt Module I Signal Signal Reference Reference PCM i Signal Signal Reference i AF ECM 74 C1 BLU 25 C2 RED 8 48 C1 BLU EI EN EIN C002 BLU YEL 410 GRY 2704 TAN 472 YEL 410 TAN 472 GRY 2701 A B D YEL 017 410 TAN YEL 410 018 472 TAN 472 GRY 022 A 2704 GRY 2704 A Engine Intake Air Manifold ren Teta Absolute ECT Sensor Pressure Sensor MAP Sensor A B A 8 LT GRN 432 LT GRN DK BLU 417 ORN BLK 469 S020 ORN BLK 021 BLK 2761 BLK 2760 BLK 2752 469 B DK BLU ORN BLK 469 SH E F E M Ore qid c LT GRN 42 ORN N co C1 C2 C1 C1 pkelu 417 BLK ir GRN 422 80 de BLU 57 RED 60 BLU 24 C2 RED 54 BLU 32 C2 RED NY 28 VJ 44 dr C002 BLU Sensor RES Senor tege TP Sensor pene Sensor MAP Sensor P i TPSensor Sensor MAPSenso 1 Ground Ground Ground Signal Ground Signal 1 Signal Ground Signal 1 1 GE AN Powertrain Control Module PCM Alternative Fuel Engine Control Module AF ECM Circuit Description Conditions for Running the DTC The Engine Coolant Temperature ECT sensor is a e Engine run time is greater than 500 seconds thermistor The ECT thermistor has high resistance e AF ECM DTCs P0112 23 P0113 25 P0117 when cold and low resistance when hot The PCM 15 or P0118 14 are
2. 2002 LPG G Van Service Manual Supplement Page 37 QUANTUM PROPANE FUEL SYSTEM to 4 0 w c If the vehicle has a hard start or poor 9 This step checks for proper air valve operation idle check for proper operation of the idle control 19 This determines if fuel is available from the fuel solenoid ICS tank supply system 6 This step checks the base mechanical LPR output pressure by disabling all fuel control devices AF Fuel System Diagnosis ation Value s Were you referred to this procedure by a DTC Go to Step 3 Go to Step 2 diagnostic chart Eet Perform the AF On Board Diagnostic OBD System Go to the applicable DTC Table Go to Step 3 Verify that the LPG fuel tank has a minimum of 1 4 tank of fuel Does the vehicle have fuel Go to Step 4 Check Connect a water column gauge or a manometer Go to Step 5 Go to Step 8 Are any DTCs present in the AF ECM to the secondary test port of the low pressure regulator LPR Start the engine and allow it to reach operating temperature Does the engine start and run 1 Disconnect the ICS and FCS electrical connectors Note This action may cause a DTC to be set by the PCM or AF ECM 4 5 to 2 With the engine idling observe the pressure 2 0 we reading on the secondary test port Go to AF Fuel Control System Is the fuel pressure WITHIN the specified range Diagnosis Go to Step 7 Inspect the air intake stream between the mixer assembly and the thrott
3. The Last Test Failed status will clear when the DTC runs and passes The AF ECM will turn OFF the MIL after THREE consecutive drive trips that the DTC runs and passes The History status will clear after FORTY consecutive WARM UP cycles with NO failures of ANY DTC All information can be cleared using a scan tool Interruption of Control Module AF ECM PCM power and ground MAY clear DTC information Clearing DTC information with this method is inconsistent and should not be performed Diagnostic Aids The most likely cause of this DTC is an improperly operating engine coolant system and thermostat Refer to Engine Cooling in the GM G VAN service manual to verify proper cooling system and thermostat operation Fault Not Present Fault Not Present indicates the condition that caused the DTC to set is intermittent and not currently present Refer to Intermittents in Symptom diagnosis for additional information If any additional DTCs were stored proceed to the applicable DTC table in the order stated in the OBD System Check Test Description The numbers below refer to the step numbers on the diagnostic table 2 Verify that the engine reaches proper operating temperature in a timely manner before continuing with ECT sensor diagnosis 3 This step determines if the AF ECM can monitor an open ECT signal circuit high voltage 4 This step determines if the AF ECM can monitor a shorted EC signal circuit 5 This step de
4. QUANTUM PROPANE FUEL SYSTEM DTC P0108 DTC 33 MAP Sensor Circuit High Voltage Circuit Description The manifold absolute pressure MAP sensor is a pressure sensor The PCM supplies about 5 volts on the MAP sensor reference voltage circuit The PCM also supplies a ground circuit to the MAP sensor When manifold vacuum is low the MAP signal voltage rises to near 4 5 volts As manifold vacuum increases the MAP signal voltage drops to around 1 0 volt The PCM and the AF ECM monitor MAP signal voltage and determine the vacuum within the intake manifold The vehicle also uses the MAP sensor to determine the barometric pressure when the ignition switch is turned ON and the engine is NOT cranked This BARO reading may also be updated whenever the engine is operated at wide open throttle This DTC is used to indicate a MAP sensor signal voltage that is above the normal operating range of the sensor DTC is a type B DTC Conditions for Running the DTC e The engine speed is greater than 500 RPM e DTCs P0121 P0122 or P0123 are not set Website 9 2 03 Rl ts 1 Bowartrain ENEE Alternative Fuel i Control i Engine Control 1 ECT Sensor IAT Sensor 5 Volt 5Volt Module f ECT Sensor IAT Sensor 5 Volt Module 1 Signal Signal Reference Reference PCM 1 Vi EE Signal D Zens __ AF ECM 74 C1 BLU 25 NN C2 RED 8 C1 BLU IRAN IBAN 294 C002 BLU YEL 410 GRY 2704 TAN 472 YEL 410 TAN 472
5. Inspect all 5 volt reference circuits for a short to ground The 5 volt reference circuits A and B are shared with the PCM The short may be located on either circuit Disconnect the AF ECM connector that contains the 5 volt reference circuit to determine if the AF ECM is the cause of the short Disconnect the other sensors that are connected to the PCM 5 volt reference circuit to determine if a sensor is the cause of the short Repair wiring or replace components as necessary Was a repair made Go to Step 14 Replace the MAP sensor Refer to MAP Sensor Replacement in Engine Controls in the GM G Van service manual Is the replacement complete Go to Step 14 Important The following PCM replacement procedures must be completed before attempting to operate the vehicle 1 Replace the PCM Refer to PCM Replacement in Engine Controls in the GM G Van service manual Program flash the replacement PCM with the correct LPG software and calibration Is the replacement complete Go to Step 14 Replace the AF ECM Refer to AF ECM Replacement Is the replacement complete Go to Step 14 Using the scan tool clear the DTC information from BOTH control modules Operate the vehicle under the Conditions for Running the DTC Using the scan tool parameter DTC STATUS ensure that this DTC runs Did this DTC RUN and PASS System OK Go to Step 2 2002 LPG G Van Service Manual Supplement Page 64 Website 9 2 03
6. Operate the vehicle under the Conditions for Running the DTC Using the scan tool parameter DTC STATUS ensure that this DTC runs Did this DTC RUN and PASS System OK Go to Step 2 2002 LPG G Van Service Manual Supplement Page 154 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM DTC P0336 DTC 41 CKP Sensor Circuit Performance Alternative Fuels Engine Speed Operation AFO TACH Signal Control RED 2531 RED 2531 Engine Speed Alternative Fuels TACH Signal Operation AFO Output Signal Circuit Description The PCM outputs an engine speed tach signal to the AF ECM This RPM signal is determined by the PCM based on a signal from the crankshaft position CKP sensor signal The CKP sensor is supplied with ignition voltage and ground The CKP sensor is mounted near the crankshaft and monitors a toothed crankshaft reluctor wheel As the crankshaft spins the toothed reluctor wheel induces a signal to the CKP sensor The PCM and the AF ECM use the CKP signal to determine engine speed crankshaft position and if a cylinder misfire is present This DTC is used to indicate no CKP reference signal is being monitored by the AF ECM while engine sensor condition indicate the crankshaft is rotating This is a type A DTC Website 9 2 03 Alternative Fuel Vehicle Speed Engine Control Signal VSS Module AF ECM 15 C002 BLU DK GRN WHT DK GRN WHT 025 DK GRN To IP Cluster and Cruise Contr
7. Operate the vehicle within the conditions for running the DTC and the parameters observed when the DTC set Observe the short term fuel trim values Do the fuel trim values indicate a rich mixture condition is present or does a fuel trim DTC set Go to Step 7 Go to Step 6 Are there any DTCs stored that have not been diagnosed Go to Go to AF DTC List Intermittents Goto Step 14 Goto Step 8 Go to Step 14 Go to Step 9 2002 LPG G Van Service Manual Supplement Page 152 Perform the AF Fuel System diagnosis and return to this step Refer to AF Fuel System diagnosis Was a LPG fuel system problem found and repaired Inspect the oxygen sensor signal and low circuits for continuity between the AF ECM connector terminals and the oxygen sensor connector terminals Inspect these circuits for shorts to other circuits or to ground Ensure the oxygen sensor gasoline control module and the AF ECM connectors are disconnected before testing circuits Repair the wiring as necessary The fault is not present Refer to Diagnostic Aids Lei Was a wiring repair made Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM tion Y Values Yes Ne Reconnect all disconnected or removed components Using the scan tool clear all DTC information form both the PCM and the AF ECM Using the scan tool communicate with the AF ECM and reset the fuel trim values to zero Turn the ignition OFF and wait 30 seconds Start the engi
8. Program flash the replacement PCM with the correct LPG software and calibration Is the replacement complete Go to Step 16 System OK Go to Step 2 2002 LPG G Van Service Manual Supplement Page 106 Did this DTC RUN and PASS Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM DTC P0132 DTC 45 HO2S Circuit High Voltage Bank 1 Sensor 1 a Alternative Fuel 4 Powertrain Hot in Run And Start 1 1 1 1 LI HO2S HO2S Control HO2S HO2S Engine Control 1 B1S1 B1S1 1 B181 B1 1 Undemood Signal Low 1 Module PCM Signal Low Module AF ECM Fuse Relay s ae ee ok eei me n Np See eke ee ee er V Center 69 29 NA A BLU ECH VE C001 CLR PPL WHT 1665 HO2S Bank 2 Sensor 1 TAN WHT 1665 C004 E TAN WHT TAN WHT 1653 C004 1653 027 TAN WHT A 1653 HO2S B1 1 B1S1 Signal Ignition Power Heated Oxygen Sensor HO2S Bank 1 Sensor 1 HO2S Bank A7 K Sensor 1 6103 Circuit Description Conditions for Running the DTC The heated oxygen sensor is used to determine the e Engine speed is greater than 400 RPM oxygen content of the engine s exhaust The oxygen e Engine coolant temperature is greater than content indicates when the engine is operating lean 160 F 70 C or rich When the engine is operating lean the e The oxygen sensor has been at operating exhaust will have more oxygen content Once at temperature for at
9. 1 Signal Ground Signal 1 1 GE a Powertrain Control Module PCM Alternative Fuel Engine Control Module AF ECM Conditions for Running the DTC e The engine is operating e The engine has been operating for greater than 2 seconds e No AF ECM DTCs are set e The engine MAP is less that 45 kPa e The TP sensor angle has changed less than 2 for at least two seconds continuously Conditions for Setting the DTC The TP sensor angle is greater that the specified percentage at the given engine speed 2002 LPG G Van Service Manual Supplement Page 85 QUANTUM PROPANE FUEL SYSTEM Action Taken When the DTC Sets The AF ECM will illuminate the MIL and store the DTC as History after one drive trip in which the diagnostic runs and fails The AF ECM will record operating conditions at the time the DTC sets This information will be stored as Freeze Frame data Conditions for Clearing the MIL DTC The Last Test Failed status will clear when the DTC runs and passes The AF ECM will turn OFF the MIL after THREE consecutive drive trips that the DTC runs and passes The History status will clear after FORTY consecutive WARM UP cycles with NO failures of ANY DTC All DTC information can be cleared using a scan tool Interruption of Control Module AF ECM PCM power and ground MAY clear DTC information Clearing DTC information with this method is inconsistent and should not be performed Diagnostic Aids Fa
10. 469 020 432 ORN BLK 021 BLK 2761 BLK 2760 BLK 2752 D 469 S019 DK BLU ORN BLK 469 A i E Ge E C005 LT GRN 432 ORN C1 c2 C1 C1 pk BLU 417 P rend 432 80 de BLU S e 90 BLU 24 C2 RED 54 BLU 32 C2 RED 27 y 728 dj 4 dr C002 BLU Sensor Sensor Sensor TP Sensor Sensor MAP Sensor TP Sensor Sensor MAP Sensor Ground Ground Ground Signal Ground Signal Signal Ground Signal Alternative Fuel Engine Control Module AF ECM Conditions for Running the DTC The engine is operating Conditions for Setting the DTC The AF ECM monitors a TP sensor signal voltage of greater than 4 9 volts for at least 1 second continuously Action Taken When the DTC Sets e A first failure of this DTC will NOT illuminate the MIL and will store as Lest Test Failed but not as History e The AF ECM will illuminate the MIL and store the DTC as History after TWO consecutive drive trips that the diagnostic runs and fails e The AF ECM will record operating conditions at the time the DTC sets This information will be stored as Freeze Frame data 2002 LPG G Van Service Manual Supplement Page 94 QUANTUM PROPANE FUEL SYSTEM Conditions for Clearing the MIL DTC The Last Test Failed status will clear when the DTC runs and passes The AF ECM will turn OFF the MIL after THREE consecutive drive trips that the DTC runs and passes The History status will clear after FORTY consecutive WARM UP cycles with NO failures
11. Clear the DTC information using the scan tool Reset the fuel trim values Start and idle the engine until normal operating temperature is reached Use the scan tool to monitor the HO2S B1 S1 voltage Is the voltage fixed within the specified range The condition that set this DTC is not present This DTC may have been set by one of the following conditions Water intrusion of the HO2S connector An intermittently open HO2S high signal circuit An intermittently open HO2S low circuit An HO2S low circuit with high resistance to ground Any AF ECM ground circuits with high resistance to ground An inoperative HO2S heater A faulty HO2S or PCM terminal contact An exhaust system leak typically within 12 inches upstream of the HO2S A defective HO2S Repair any of the above conditions as necessary Was a condition found and repaired The fault is not present Refer to Diagnostic Aids Are any DTCs stored that have not been diagnosed Website 9 2 03 Go to AF Powertrain OBD System heck Ce Go to Step 2 SE Go to Step 5 Go to Step 3 i Go to Step 22 Go to Step 4 0 1 to 1 0 volts Go to AF DTC List Go to Intermittents 2002 LPG G Van Service Manual Supplement Page 115 QUANTUM PROPANE FUEL SYSTEM Value s ves mo Use a scan tool to establish communication with the AF ECM Start and idle the engine until normal operating temperature is reached 0 10 to 1 0 Use the scan tool to mon
12. QUANTUM L O G Liquefied Petroleum Gas LPG Fuel System For 2002 GM 5 7L G Van Website 103133 Liquefied Petroleum Gas LPG Fuel System For 2002 GM 5 7L G Van This manual provides information on the diagnosis the service procedures the adjustments and the specifications for the Liquefied Petroleum Gas LPG Fuel System as used on the 2002 GM 5 7L G Van This manual is a supplement to be used with 2002 GM G Van service manual IMPORTANT Perform the Alternative Fuels Powertrain On board Diagnostic AF OBD System Check on page 20 before contacting QUANTUM Technical Assistance at 1 800 816 8691 GENERAL MOTORS GM and the GM emblem are registered trademarks of General Motors Corporation and are used herein with the permission of General Motors Corporation All information illustrations and specifications in this manual are based on the latest product information available at the time of publication QUANTUM Technologies Inc reserves the right to make changes at any time without notice No part of this manual may be reproduced stored in any retrieval system or transmitted in any form or by any means including but not limited to electronic mechanical photocopying and recording without prior written permission of QUANTUM Technologies Inc 2001 QUANTUM TECHNOLOGIES INC QUANTUM PROPANE FUEL SYSTEM CONTENTS Vehicle Application EE 5 Propane Fuel System Cautions ccceeeeceeeeeeeeeeeeeee
13. e Tighten the nuts and bolts to 105 Nem 77 lb ft Verify the tank and bracket is secure Remove the tank lifting support device Connect the following fuel lines to the tank e Liquid level gauge Tighten to 16 Nem 12 lb ft e Fuel in from fill valve Tighten to 47 Nem 35 Ib ft e Fuel out at fuel tank lock off Tighten to 37 Nem 27 lb ft Connect the following electrical connectors e Fuel tank lock off e Fuel sending unit FSU Connect the negative battery cable Start the vehicle and leak check the propane fuel system at each serviced fitting Install the fuel tank cover and mounting bolts e Tighten the bolts to 22 Nem 16 lb ft 2002 LPG G Van Service Manual Supplement Page 186 PROPANE FUEL TANK DRAINING CAUTION To prevent the risk of fire and personal injury do not attempt to drain a propane fuel tank You or someone else could be injured Draining a propane fuel tank requires trained personnel and special equipment Contact a local propane distributor to drain the fuel tank CAUTION The propane fuel tank contains liquid and vaporous propane at pressures up to 312 psi Failure to drain the tank before service may cause fire and or personal injury 1 Contact a local propane distributor to drain the propane fuel tank 2 After draining a small amount of propane vapor will remain in the tank Vent the vapor in a safe approved manner following all guidelines and regulations Refer
14. Go to Step 22 Goto Step 20 2002 LPG G Van Service Manual Supplement Page 139 Did you complete the repair Repair the HO2S heater ignition or ground circuit Possible causes include the following An open circuit A high circuit resistance A faulty ground connection A blown heater fuse other DTCs may be set Did you complete the repair Repair the high resistance between the HO2S low circuit and the PCM ground circuit Possible causes include the following A faulty HO2S connector terminal contact An open sensor harness low circuit requires HO2S replacement A sensor harness low circuit with high resistance requires HO2S replacement A faulty PCM ground connection A high PCM ground circuit resistance An ungrounded exhaust system Did you complete the repair 1 Inspect for exhaust system leaks upstream of the suspect HO2S The leak may be very small and is typically within 12 inches of the HO2S 2 Repair the exhaust as necessary Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Sep on Vaw Ye Ne Inspect the oxygen sensor signal and low circuit for continuity between the AF ECM connector terminals and the oxygen sensor connector terminal Inspect these circuits for shorts to other circuits or to ground Ensure the oxygen sensor PCM and the AF ECM connectors are disconnected before testing the circuits 3 Repair the wiring as necessary Go to Step 22 Goto Step 18 Go to Step 22 Go to Step
15. HO2S Bank 1 4 amp Sensor 1 PNK C004 TAN C004 Ignition Power E Se Heated on Bank 2 Sensor 1 HO2S Bank 4 Sensor 1 G103 Circuit Description bias voltage sometimes referred to as activity or switching can be monitored with the HO2S signal The heated oxygen sensor is used to determine the voltage oxygen content of the engine s exhaust The oxygen The oxygen sensor contains a heater The heater content indicates when the engine is operating lean quickly warms the sensor to operating temperature or rich When the engine is operating lean the The heater will also maintain operating sensor exhaust will have more oxygen content Once at temperature during extended idle conditions operating temperature the HO2S will produce a This DTC is used to indicate an HO2S with in active voltage in relation to the oxygen content of the signal voltage exhaust The HO2S requires an operating This DTC is a type B DTC temperature of 600 F 360 C to produce voltage The HO2S will produce more voltage when the Conditions for Running the DTC exhaust is rich and less voltage when the exhaust is lean The HO2S operating range is around 0 10 e Engine speed is greater than 400 RPM volts 100 mV to 1 volt 1000 mV e The engine has been operating for at least 1 The PCM supplies a bias or reference voltage to the minute HO2S This bias voltage is around 450 mV e The oxygen sensor has been at operating This DTC is used to indicate an HO2S
16. Hg of vacuum applied to the MAP sensor 34 kPa Is the value less than the value shown Go to Step 5 Go to Step 8 Disconnect the hand vacuum pump from the MAP Go to Step 6 Go to Step 8 sensor The MAP sensor display should return to the value recorded in Step 2 Does the MAP sensor display return to the recorded value Observe and compare the TP sensor data parameter with the throttle at rest to the first specified value The TP sensor should equal the first value or less Observe and compare the TP sensor data parameter with the throttle fully open to the d second specified value The TP sensor should 2 to 98 equal the second value or greater Go to DTC P0121 Throttle Does the TP sensor display indicate the values as GE expected Go to Step 7 Performance The fault is not present Refer to Diagnostic Go to Go to Intermittent AF DTC List Conditions Go to Step 9 Go to Step 10 Go to Step 11 Go to Step 11 mE System OK Go to Step 2 2002 LPG G Van Service Manual Supplement Page 60 Aids Are any DTCs stored that have not been diagnosed 1 Inspect for proper terminal contact 2 Inspect the MAP sensor ground circuit for an open or high resistance between the MAP sensor connector and the PCM connector terminal Was a problem found Repair the connections or circuit as necessary Refer to Wiring Repairs in the GM G Van Service Manual Is the action complete Replace the MAP sensor Refer to MAP Sensor Replacem
17. Ju SSew 1euBig Josues dV aau zo EEN INOd 9Inpo 10 u09 ueJy Mod jeubls bop LHW jg punog 4 MOqd uoniub sjuauodul0 WIO OL Jeu Aejoy esny pooylapun 2002 LPG G Van Service Manual Supplement Page 13 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Heated Oxygen Sensor HO2S Bank 1 Sensor 1 419 1009 W03 4Y eInpoyy 01 uo9 euiDu3 9N eAneuJejyv gt punoJc L Josueg LH Xueg SCOH Josues ueD xo peyeey JOMOg Uoniub V IHANNYV L S9 COOL v009 e994 S994 LHAWNVL Daat LHAVNVL 3 v009 S991 LHM dd LHM NVL S99 LHAW lad LHW Idd 69 49JU99 EINE A S SE e Aejoy asn4 eum isig Od eINPOW ere EC Dem jONUCD i SZOH SZOH SZOH SZOH ule JJeA 0d d 1 uejs Puy uny ur 30H L 40Sueg zi xueg ScOH L j0suog RE SZOH 2002 LPG G Van Service Manual Supplement Page 14 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Heater Oxygen Sensor HO2S Bank 2 Sensor 1 419 1009 INO3 4Y SINPON jo3uo aulbuy 9N Y eAgeuaejv L Josues z xueg SZOH Josues uoD xQ pajesH L991 na Lo Wod SINPON o3uo2 utelJeMOd 1 9991 Idd 99 jeu amp is LS cd L Josueg L yUeg SZOH punoJo Jamo uoniuB L Josueg gt isaueg ScOH Jee Ke 9 osn4 poouiepur Hels puy Uny ui JOH 2002 LPG G Van Service Manual Supplement Page 15 Website 9 2 03
18. The PCM also supplies a ground circuit to the ECT sensor When ECT resistance is high cold sensor the ECT signal voltage remains near the supplied 5 volts As the ECT sensor warms and resistance drops signal voltage is pulled lower to the sensor ground The PCM and the AF ECM monitor the ECT signal circuit voltage to determine engine temperature This DTC is used to indicate an ECT signal voltage that is above the normal operating range of the sensor This is a type B DTC Website 9 2 03 Conditions for Running the DTC The engine has been operating for greater than 5 seconds when the intake air temperature is greater than 0 C 32 F OR The engine has been operating for greater than 10 minutes when the intake air temperature is less than 0 C 32 F Conditions for Setting the DTC The AF ECM monitors an ECT sensor signal voltage greater that 4 9 volts for at least 5 seconds continuously Action Taken When the DTC Sets e A first failure of this DTC will NOT illuminate the MIL and will store as Lest Test Failed but not as History e The AF ECM will illuminate the MIL and store the DTC as History after TWO consecutive drive trips that the diagnostic runs and fails 2002 LPG G Van Service Manual Supplement Page 81 QUANTUM PROPANE FUEL SYSTEM The AF ECM will record operating conditions at the time the DTC sets This information will be stored as Freeze Frame data Conditions for Clearing the MIL DTC Th
19. The OBD is the starting point for any driveability intermittent malfunction concern diagnosis The OBD directs the service technician to the next logical step in diagnosing the Check any circuitry that is suspected of causing an concern This system check will address possible intermittent condition for the following conditions faults in two separate control module systems To e Backed out terminals avoid unnecessary diagnostic time follow the system check carefully Improper mating Broken locks Improperly formed or damaged terminals Poor terminal to wiring connections Physical damage to the wiring harness e Corrosion Perform this check ONLY if there is a driveability complaint or if you have been sent to this system check from another section in the service information Test D ipti ith S Tool Understanding the table properly reduces the estiDescniplon wi can Tool diagnostic time Proper use of the OBD helps The numbers below refer to the step numbers on the prevent the unnecessary replacement of good parts diagnostic table Diagnostic Aids 1 This step verifies that the MIL is functioning 2 This step determines if the scan tool can Important communicate with the PCM e Do not clear DTCs unless directed bya 3 This step determines if the scan tool can diagnostic procedure Clearing the DTCs will communicate with the AF ECM also clear valuable Freeze Frame and Failure 6 This step verifies that the engine will s
20. that the diagnostic runs and fails The AF ECM will record operating conditions at the time the DTC sets This information will be stored as Freeze Frame data Conditions for Clearing the MIL DTC The Last Test Failed status will clear when the DTC runs and passes The AF ECM will turn OFF the MIL after THREE consecutive drive trips that the DTC runs and passes The History status will clear after FORTY consecutive WARM UP cycles with NO failures of ANY DTC QUANTUM PROPANE FUEL SYSTEM Diagnostic Aids Fault Not Present Fault Not Present indicates the condition that caused the DTC to set is intermittent and not currently present Refer to Intermittents in Symptom diagnosis for additional information If any additional DTCs were stored proceed to the applicable DTC table in the order stated in the OBD System Check Preliminary Checks Low or empty LPG fuel tank For proper LPG fuel system operation liquid fuel is required at the LPR inlet If the fuel level becomes so low that fuel vapor is delivered to the LPR inlet the air fuel mixture will be lean and the MIL may illuminate Also the vehicle will start and idle normally but hesitate and stumble under load If the DTC is current verify that the fuel tank is at least Y4 full If the DTC is stored in history verify with the operator if the vehicle has recently been run low or out of fuel A heated oxygen sensor pigtail may be mis routed and contacting the exhaust ma
21. 2 gms sec Go to Step 5 Go to Step 3 2 2 gms sec Go to Step 9 Go to Step 4 2002 LPG G Van Service Manual Supplement Page 51 Go to AF DTC List Go to Intermittents QUANTUM PROPANE FUEL SYSTEM Sep amn O Values Inspect the air intake system between the MAF sensor and the throttle body for leaks Was a problem found and ired P RAPI RRAS Go to Step 18 Go to Step 6 1 Turn the engine OFF leaving the ignition ON 2 Disconnect the MAF sensor connector 3 Connect a DVOM between the MAF signal circuit 5 0 volts and ground Is the voltage near the specified value Go to Step 10 Go to Step 7 Inspect the MAF sensor signal circuit for an open or high resistance between the sensor connector and the POM If the circuit voltage is greater than 5 2 volts inspect the MAF sensor signal circuit for a short to voltage 3 Inspect for proper terminal contact at both the PCM and the MAP sensor connector 4 Repair wiring or terminal contact as necessary Was a wiring or terminal repair necessary Go to Step 18 Goto Step 8 Inspect the MAF sensor signal circuit for a short to engine ground or to the sensor ground circuit Disconnect the AF ECM connector containing the MAF sensor signal circuit to determine if the AF ECM is the cause of the short Repair the wiring as necessary Is a repair or replacement necessary Go to Step 18 Go to Step 16 Inspect the MAF sensor signal circuit for an open or high resistance betwe
22. 2002 LPG G Van Service Manual Supplement Page 97 Value s Turn on the ignition OFF Disconnect the AF ECM connector that contains the TP signal circuit Disconnect the TP sensor connector Test the TP signal circuit for continuity with a DVOM Does the DVOM indicate continuity Repair the open TP signal circuit between the TP signal circuit splice and the AF ECM Is the circuit repair complete 1 Inspect for proper terminal contact at the AF ECM connector 2 Repair terminal contact as necessary Was a terminal repair made Replace the TP sensor Refer to TP Sensor Replacement in Engine Controls in the GM G Van service manual Is the replacement complete Important The following PCM replacement procedures must be completed before attempting to operate the vehicle 1 Replace the PCM Refer to PCM Replacement in Engine Controls in the GM G Van service manual Program flash the replacement PCM with the correct LPG software and calibration Is the replacement complete Replace the AF ECM Refer to AF ECM Replacement Is the replacement complete Using the scan tool clear the DTC information from BOTH control modules Operate the vehicle under the Conditions for Running the DTC Using the scan tool parameter DTC STATUS ensure that this DTC runs Did this DTC RUN and PASS Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM DTC P0125 DTC 16 ECT Excessive Time to Closed Loop
23. 33 Manifold Absolute Pressure MAP Sensor Circuit High Voltage DTC P0112 23 Intake Air Temperature IAT Sensor Circuit Low Voltage DTC P0113 25 Intake Air Temperature IAT Sensor Circuit High Voltage DTC P0117 15 Engine Coolant Temperature ECT Sensor Circuit Low Voltage DTC P0118 14 Engine Coolant Temperature ECT Sensor Circuit High Voltage Ap vwe As Ww 8B Ye EN EN M uM E E DTC P0122 22 Throttle Postion TP Sensor Circuit Low Vallage B vs DTC P0123 21 Throttle Position TP Sensor Circuit High Voltage B Yes E O B Ye e Ye RAIDER B Ye e Ye B Ye A Ye MERINO PAEZ E RERUM B vs A vs Ea A es Closed Loop Fuel Control A DTC P1215 27 Quad Driver Output Circuit LB Yes A A A A A A Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes es 2002 LPG G Van Service Manual Supplement Page 24 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Alternative Fuels AF Powertrain OBD System Check Circuit Description cause the AF ECM to store multiple false codes Refer to Engine Controls Schematics The On Board Diagnostic OBD System Check is an organized approach to identifying a problem Inspect all related wiring and connections including created by a control module system malfunction the connections at the PCM These may cause an
24. 5V Is the voltage within the specified value Go to Step 6 Go to Step 5 Connect the DVOM between a chassis ground and FSU connector pin A 9 6V 13 5V ithi ifi 2 Is the voltage within the specified value Go to Step 8 Go to Step 7 Inspect the Fuel Level Sensor circuit between Go to Step 10 Go to Step 9 FSU connector pin C and AF connector C301 pin B for the following Go to Step 10 EN Go to Step 10 ul High resistance Poor terminal contact Goto Fuel Gauge Inaccurate or Inoperative Gas in the G van Service Go to Step 10 Manual System OK Opens 2002 LPG G Van Service Manual Supplement Page 49 Verify the LPG fuel level by filling until liquid appears at the liquid level gauge Shorts 2 Repair wiring or terminal contact as necessary Was a wiring or terminal repair made Repair the AF FSU power circuit Is the action complete Repair the AF FSU ground circuit Is the action complete Replace the fuel sending unit Refer to Fuel Sending Unit Replacement Does the fuel gauge read correctly 1 Disconnect all test equipment 2 Start the engine 3 Using SNOOP or equivalent leak check any fuel system repairs made Is the action complete Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM DTC P0102 DTC 36 MAF Sensor Circuit Low Frequency To OEM Components Ignition Power Ground BLKANHT 451 Circuit Description The MAF sensor is an air flow meter The MAF sensor is su
25. 7 This step determines is the IAT signal circuit wiring is the open condition 11 If the connector terminals pass inspection test the sensor signal circuit for a short to a 5 volt reference circuit Although an unlikely failure this condition should be diagnosed before replacing the PCM DTC P0113 DTC 25 IAT Sensor Circuit High Voltage Did you perform the Alternative Fuels AF Powertrain On Board Diagnostic OBD System Check 1 Using the scan tool establish communication with the PCM 2 Observe the IAT sensor data parameter Does the IAT sensor data parameter indicate IAT voltage greater than the specified value 1 Using the scan tool establish communication with the AF ECM 2 Observe the IAT sensor data parameter Does the IAT sensor data parameter indicate IAT voltage greater than the specified value The fault is not present Refer to Diagnostic Aids Are there any DTCs stored that have not been diagnosed Website 9 2 03 Value s 4 9 volts Yes No Go to AF Powertrain OBD System heck Go to Step 2 SES Go to Step 5 Go to Step 3 4 9 volts Go to Step 12 Go to Step 4 Go to Go to AF DTC List Intermittents 2002 LPG G Van Service Manual Supplement Page 74 QUANTUM PROPANE FUEL SYSTEM Yes No Go to Step 8 Go to Step 6 Go to Step 9 Go to Step 7 Go to Step 11 Goto Step 10 Value s Disconnect the IAT sensor 2 Connect a fused jumper between the IAT sensor connector termin
26. AF ECM contains electronic devices called output driver modules The output driver modules provide switchable outputs control circuits for operating solenoids telltales and other devices Each of the outputs has an internal fault line that the AF ECM can monitor for faulted circuit conditions This DTC is used to indicate that the AF ECM fault line has monitored a control circuit fault Monitored control circuits include the following e The AF Enable Output control circuit e The underhood low pressure lock off LPL e The fuel solenoid control FCS e The idle control solenoid ICS This is a type A DTC Conditions for Running the DTC The ignition is ON Website 9 2 03 RED 920 RED 920 S011 S005 Underhood Fuel Control DIODE Solenoid 3 FCS DIODE 2 Solenoid S009 002 LT BLU 901 LT GRN 911 1 8 C001 CLR UH Low Pressure Lock off LPL Fuel Control Solenoid FCS Solenoid Signal i Conditions of Setting the DTC The AF ECM monitors a control circuit fault for at least one second continuously Action Taken When the DTC Sets e The AF EOM will illuminate the MIL and store the DTC as History during ONE drive trip that the diagnostic runs and fails e The AF ECM will record operating conditions at the time the DTC sets This information will be stored as Freeze Frame data Conditions for Clearing the MIL DTC e The Last Test Failed status will clear when the DTC runs and passes e T
27. B1 S1 connector Leave the AF ECM disconnected Jumper the HO2S low circuit terminal engine 351 to 551 harness side to a known good ground mV Turn the ignition ON while leaving the engine OFF Using a scan tool monitor the HO2S B1 S1 voltage Is the HO2S voltage within the value range specified Go to Step 8 Go to Step 9 The HO2S may be detecting a lean exhaust Go to Step 16 Go to Step 15 Go to Step 10 Go to Step 16 EN Go to Step 16 Go to Step 13 2002 LPG G Van Service Manual Supplement Page 105 condition Inspect for one of the following conditions HO2S connector water intrusion Exhaust leak between the HO2S and the engine Vacuum leaks An inaccurate MAF sensor Repair any of the above or similar engine conditions as necessary Was a condition found and repair Repair the HO2S signal circuit high circuit shorted to ground or shorted to the HO2S low circuit Is the action complete Test the HO2S high and low circuits for continuity between the engine harness circuit splices and the AF ECM connector terminals Measure for continuity between the oxygen sensor connector and the AF ECM connector Test for proper terminal contact at the AF ECM connector terminals and at the 10 way LPG harness to engine harness connector terminals Repair wiring or terminals as necessary Was a wiring or terminal repair made Turn the ignition OFF Remove the jumper form the HO2S low circuit terminal Dis
28. DTC P0118 DTC 14 Engine Coolant Temperature ECT Sensor Circuit High Voltage A IR A EE e T Powertrain Alternative Fuel i Control i Engine Control 1 ECT Sensor AT Sensor 5 Volt 5Volt 1 Module ECT Sensor IAT Sensor 5Volt 1 Module Signal Signal Reference Reference PCM ON Si ignal sionals Ee Reference __ AF ECM 74 C1 BLU 25 C2 RED 8 48 C1 BLU 12 N 197 29 C002 BLU YEL 410 GRY 2704 TAN 472 YEL 410 TAN 472 GRY 2701 A B D YEL 017 410 TAN YEL 410 018 472 TAN 472 GRY 022 A 2704 GRY 2704 A Engi Intake Ai A Coolant T mperituig Meme Temperature IAT solu ECT Sensor Pressure Sensor MAP Sensor A B A 8 LT GRN 432 LT GRN DK BLU 417 ORN BLK 469 S020 ORN BLK 021 BLK 2761 BLK 2760 BLK 2752 469 019 DK BLU ORN BLK 469 SH E E DK BLU 417 mT M C005 LT GRN 432 ORN BLK 469 c ES c1 c1 DK BLU 417 LT GRN 432 80 y BLU 57 y RED GO BLU 24 C2 RED 54 BLU 324 C2 RED NY 28 NJ 44 y coo2 BLU Sensor Sensor Sensor TP Sensor Sensor MAP Sensor TP Sensor Sensor MAP Sensor Ground Ground Ground Signal Ground Signal Signal Ground Signal Powertrain Control Module PCM Alternative Fuel Engine Control Module AF ECM Circuit Description The Engine Coolant Temperature ECT sensor is a thermistor The ECT thermistor has high resistance when cold and low resistance when hot The PCM supplies about 5 volts on the ECT signal circuit
29. DTC information with this method is inconsistent and should not be performed Diagnostic Aids Check for the following conditions e Low or empty LPG fuel tank For proper LPG fuel system operation liquid fuel is required at the LPR inlet If the fuel level becomes so low that fuel vapor is delivered to the LPR inlet the air fuel mixture will be lean and the MIL may illuminate Also the vehicle will start and idle normally but hesitate and stumble under load If the DTC is current verify that the fuel tank is at least 1 4 full If the DTC is stored in history verify with the operator if the vehicle has recently been run low or out of fuel Fault Not Present Fault Not Present indicates the condition that caused the DTC to set is intermittent and not currently present Refer to Intermittents in Symptom diagnosis for additional information If any additional DTCs were stored proceed to the applicable DTC table in the order stated in the OBD System Check Always diagnose ANY PCM codes that are present before beginning this diagnostic procedure Check the following items e Faulty Idle Control Solenoid ICS or ICS circuit e Faulty Fuel Control Solenoid FCS or FCS circuit e Faulty fuel mixer e Faulty LPR Test Description 2002 LPG G Van Service Manual Supplement Page 146 QUANTUM PROPANE FUEL SYSTEM The numbers below refer to the step numbers on the testing the circuits for shorts the resistance diagnostic
30. DTC sets This information will be stored as Freeze Frame data 2002 LPG G Van Service Manual Supplement Page 90 QUANTUM PROPANE FUEL SYSTEM Conditions for Clearing the MIL DTC The Last Test Failed status will clear when the DTC runs and passes The AF ECM will turn OFF the MIL after THREE consecutive drive trips that the DTC runs and passes The History status will clear after FORTY consecutive WARM UP cycles with NO failures of ANY DTC All DTC information can be cleared using a scan tool Interruption of Control Module AF ECM PCM power and ground MAY clear DTC information Clearing DTC information with this method is inconsistent and should not be performed Diagnostic Aids Fault Not Present Fault not Present indicates the condition that caused the DTC to set is intermittent and not currently present Refer to Intermittents in Symptom diagnosis for additional information If any additional DTCs were stored proceed to the applicable DTC table in the order stated in the AF OBD System Check Test Description The numbers below refer to the step numbers on the diagnostic table 2 This step determines if the failure condition affects the PCM 3 This step determines if the failure condition is present 4 This step determines if the TP signal is going low only when the throttle is opened 6 This step determines if the TP sensor is the cause of the condition 7 This step determines if the 5 volt refe
31. DTCs and reset fuel trim Important If the ignition switch is not cycled OFF for 10 seconds after clearing any DTC s and the vehicle is started the AF ECM OBD system will be disabled for that key cycle Go to the Applicable DTC Table Is the action complete Crank the engine for 10 seconds Go to No Start Does the engine start Go to Step 7 in Symptoms Observe the MIL Go to A Power train On Board Diagnostic System Check in the GM G Van service manual Is the MIL ON Go to Step 8 Go to P Is there a driveability complaint NES System OK 2002 LPG G Van Service Manual Supplement Page 29 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Malfunction Indicator Lamp Circuit D2 TRANS iP Fuse Fuse 1 e 10A 1020 Underhood Fuse Relay Center 2100 Malfunction Indicator Lamp MIL C004 PNK To OEM Components 1020 139 PNK BRN WHT 419 To Ignition Relay DK BLU 919 Ignition Power Output Ground Ground Ground Ground Instrument Panel BRN WHT 419 input C001 CLR S006 Ground Back of Right Cylinder Head Circuit Description The SERVICE ENGINE SOON Malfunction Indicator Lamp is used to indicate to the driver that an engine control system malfunction has occurred that may cause an increase in emissions and or a driveability concern When the ignition is first turned ON the PCM will illuminate the MIL for a bulb and system check When the eng
32. Description The IAT sensor is a thermistor The IAT thermistor has high resistance when cold and low resistance when hot The PCM supplies about 5 volts on the IAT signal circuit The PCM also supplies a ground circuit to the IAT sensor When IAT sensor resistance is high cold sensor the IAT signal voltage remains near the supplied 5 volts As the IAT sensor warms and resistance drops signal voltage is pulled lower to the sensor ground The PCM and the AF ECM monitor the IAT signal circuit voltage to determine the temperature of the air entering the engine This DTC is used to indicate an IAT signal circuit voltage that is below the normal operating range of the sensor This DTC is a type B DTC Conditions for Running the DTC e The engine has been operating greater than 1 5 minutes e The vehicle speed is greater than 1 mph Website 9 2 03 EE 7 powertrain ici pty pete Oe ee Alternative Fuel i Control i Engine Control 1 ECT Sensor IAT Sensor 5 Volt Module f ECT Sensor IAT Sensor 5 Volt Module MN ERN ERR LS ace Reber nee comes Some EUREN tour un on Signal Signal Reference AF ECM 74 C1 BLU 25 NN C2 RED 8 C1 BLU IRAN IBAN 29 C002 BLU YEL 410 GRY 2704 TAN 472 YEL 410 TAN 472 GRY 2701 A B D YEL 017 410 TAN YEL 410 S018 472 TAN 472 GRY A 2704 2704 A Engi Intake Ai Coolant Temperature Throttle Manro Temperature IAT Position ECT Sensor TP ea Sensor
33. During normal operation the ECM commands a duty cycle to the fuel control solenoid FCS The FCS modulates air valve vacuum on top of the secondary diaphragm of the LPR By controlling the pressure on top of the LPR secondary diaphragm the ECM can control the output pressure and fuel flow to the mixer A high FCS duty cycle means the ECM is issuing a lean command to control a rich condition Website 9 2 03 A low FCS duty cycle means the ECM is issuing a rich command to control a lean condition To increase fuel control authority the ECM will also use the idle control solenoid ICS The ICS supplies additional fuel from the LPR secondary chamber below the mixer directly into the air stream The ECM will always command a duty cycle to the ICS that is the opposite or the FCS If the ECM commands an 80 duty cycle to the FCS the ECM will command a 20 duty cycle to the ICS Diagnostic Aids Always diagnose any PCM or ECM codes that are present before beginning this diagnostic procedure Refer to Important Preliminary checks and Symptom Diagnosis Charts before attempting to diagnose the AF fuel control system If the vehicle will not continue to run refer to Hard Start for preliminary checks Before proceeding with this procedure verify that the AF Fuel System Diagnosis has been performed 2002 LPG G Van Service Manual Supplement Page 43 QUANTUM PROPANE FUEL SYSTEM Check for the following conditions Diagnostic Scan Tool
34. ECT voltage less than the specified value Go to Step 3 Go to Step 4 1 Using the scan tool establish communication with the PCM 2 Observe the ECT sensor data parameter 0 019 volts Does the ECT sensor data parameter indicate ECT voltage less than the ee value Eo a Sleps Go te Sapa The fault is not present Refer to Diagnostic Aids Go to Go to Are DTCs stored that have not been diagnosed AF DTC List Intermittents Disconnect the ECT sensor 0 019 volts Does the ECT sensor data parameter indicate ECT voltage less than the specified value Go to Step 6 Go to Step 9 2002 LPG G Van Service Manual Supplement Page 78 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Value s ves mw Turn the ignition OFF Disconnect the PCM connector that contains the ECT signal circuit Disconnect the AF ECM connector that contains the ECT signal circuit With the ECT sensor connector disconnected test the ECT signal circuit for continuity to engine ground and also to the sensor ground circuit If a shorted to ground ECT signal circuit is found repair as necessary Was an ECT signal circuit repair made Go to Step 12 Go to Step 7 Connect the PCM connector that contains the ECT signal circuit Leave the AF ECM connector disconnected Turn the ignition ON with the engine OFF 0 019 volts With the ECT sensor connector disconnected observe the PCMECT sensor data parameter Does the ECT sensor data parameter indicate ECT vo
35. Fuels AF Powertrain OBD System Check 25 Malfunction Indicator Lamp Circuit e eene nnn 30 Wait to Drive Lamp Circuit eeeeeeeeeeeeeeenenen ener nnne 34 AF Fuel System Diagnosis eeeeseseeeeeeeeeee eene enne nnn nnne nn nnne nn nnn 37 AF Fuel Control System Diagnosis eese nennen enne nennen ERER EE nennen 43 LPG Fuel Sending Unit Diagnosis eeeeeeeeeeeeeeen enne nennen 48 DTC P0102 DTC 36 MAF Sensor Circuit Low Frequency eene 50 DTC P0103 DTC 37 MAF Sensor Circuit High Frequency eene 54 DTC P0106 DTC 32 MAP System Performance eeeeeeseeeeseeeeeerne 58 DTC P0107 DTC 34 MAP Sensor Circuit Low Voltage 61 DTC P0108 DTC 33 MAP Sensor Circuit High Voltage eeeeereee 65 DTC P0112 DTC 23 IAT Sensor Circuit Low Voltage se 66 DTC P0113 DTC 25 IAT Sensor Circuit High Voltage eere 73 DTC P0117 DTC 15 ECT Sensor Circuit Low Voltage 77 DTC P0118 DTC 14 ECT Sensor Circuit High Voltage c cccceseeeeeeeeeeeeeeeeeeeeees 81 DTC P0121 DTC 26 TP Sensor Performance 2 c ceeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeenees 85 DTC
36. G Van Service Manual Supplement Page 3 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM EYunoenuUtOupI ck 167 Important Preliminary Checks eeeeeeeeeeeeee enne nennen nennen nnn nnn 167 dt MS e X 168 N Mi 169 Hard E Cl a ida 171 Cuts Outs MisSOS c000codildcnii dara Ee dE eege ad 173 Hesitation Sag Stumble 2 edd Seege deed ee EEN 174 E An EE 175 Lack of Power Sluggishness or Sponginess eere 177 Poor GEN Le LEE 179 Rough Unstable or Incorrect Idle Stalling SEENEN EEN EEN 181 Surges CHug AAA A A A n ANAA 183 Repair Instructions eege ege eege EEN a 184 Propane Fuel System Pressure Relief sees 184 Propane Fuel System Leak TeSt ccceeeeceeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeseeeeeeeseeeeeeeeeeneeees 184 Propane Fill Valve Replacement eseeeeeeeee enne nennen nennen nnn nnn 184 Fuel Line Fill Valve to Tank Replacement SEENEN REENEN ENNEN 184 Propane Fuel Tank Cover Replacement eeeeeeeeeeeeeee enne nennen 185 Propane Fuel Tank Replacement eeeesseseeeeeeeeee ener 186 Propane Fuel Tank Draining eeeeeeeeeee eren nennen nenne nennen nnn nnn nnn 187 Fuel Tank Lock off Replacement cccccceeeeeeeeeeeeeeeeeeeeeeeeeneeeeeeeeeeeeseeeeeeeeeeneeees 187 Fuel Sending Unit Replacement eeeeseeseeee
37. GRY 2701 A B D YEL 017 410 TAN YEL 410 018 472 TAN 472 GRY A 2704 2704 A Engi Intake Ai ee Temperature Throttle Men wod Sensor Position Pressure TP MAP Sensor Sensor A B A B LT GRN 432 LT GRN DK BLU 417 ORN BLK 469 020 ORN BLK 021 BLK 2761 BLK 2760 BLK 2752 D 469 S019 DK BLU ORN BLK 469 A j e BEBE ad d m C005 LT GRN 432 ORN C1 c2 C1 C1 pk BLU 417 P rend 432 80 de BLU S e 90 BLU 24 C2 RED 54 BLU 32 C2 RED 27 y 7728 dj 4 v C002 BLU i Sensor Sensor Sensor TP Sensor Sensor MAP Sensor 4 i TP Sensor Sensor MAP Sensor 1 Ground Ground Ground Signal Ground Signal 1 Signal Ground Signal 1 1 GE Powertrain Control Module PCM Alternative Fuel Engine Control Module AF ECM Conditions for Setting the DTC The AF ECM monitors a MAP sensor signal voltage of more than 4 8 volts for at least 4 seconds continuously Action Taken When the DTC Sets e A first failure of this DTC will NOT illuminate the MIL and will store as Last Test Failed but not as History e The AF EOM will illuminate the MIL and store the DTC as History after TWO consecutive drive trips that the diagnostic runs and fails e The AF ECM will record operating conditions at the time the DTC sets This information will be stored as Freeze Frame data Conditions for Clearing the MIL DTC e The Last Test Failed status will clear when the DTC runs and passes 2002 LPG G Van Service Manu
38. Improper valve timing Engine compression Manifold vacuum leaks Intake manifold gaskets Sticking or leaking valves Exhaust system leakage Check the EGR operation for being open all the time Refer to EGR System Diagnosis in the GM G Van Service Manual Check the intake and exhaust system for casting flash or other restrictions 2002 LPG G Van Service Manual Supplement Page 175 QUANTUM PROPANE FUEL SYSTEM Fuel System Checks e Perform a fuel system diagnosis Refer to AF Fuel System Diagnosis Additional Checks e Proper PCM software calibrations e Check the EGR gasket for a faulty or loose fit e Check the EGR valve operation for being open all the time Refer to EGR System Diagnosis in the GM G Van Service Manual 2002 LPG G Van Service Manual Supplement Page 176 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Lack of Power Sluggishness or Sponginess DEFINITION The engine delivers less than expected power There is little or no increase in speed when partially applying the accelerator pedal Preliminary Checks Refer to Important Preliminary Checks Refer to the Alternative Fuel AF Powertrain OBD System Check Search for service bulletins Compare the customer s vehicle with a similar unit Make sure the customer has an actual problem Do not compare the power output of the vehicle operating on LPG to a vehicle operating gasoline as the fuels do have different drive feel characteristics Remove the air fi
39. LPR This vacuum signal is also used to generate lift for the mixer air valve This vacuum signal is most commonly referred to as air valve vacuum In the mixer the fuel mixes with the air entering the engine This air fuel mixture is then drawn into the engine for combustion Website 9 2 03 Diagnostic Aids This procedure is intended to diagnose a vehicle operating on LPG If the vehicle will not continue to run on LPG refer to Hard Start for preliminary checks Before proceeding with this procedure verify that the vehicle has a sufficient quantity of fuel and that liquid fuel is being delivered to the LPR Also ensure that the manual shut off override valve on the LPG tank is fully opened and that the excess flow valve has not been activated Verify air has been bled from the cooling system at the coolant bleed port Tools Required e Alen wrench for test port plugs e DVOM GM J 39200 Fluke 88 or equivalent Duty Cycle Monitoring Tool e QUANTUM Fuel System Analyzer FSA or DVOM GM J 39200 Fluke 88 or equivalent Diagnostic Scan Tool e GM Tech 2 or equivalent Pressure Gauges e Water Column Gauge Manometer GM 7333 6 or equivalent e 0 10 PSI Gauge Test Description The numbers below refer to step numbers on the diagnostic table 5 This step will determine if the fuel control solenoid FCS and fuel supply system are functioning properly The vacuum on the secondary test port will be approximately 2 0
40. P0122 DTC 22 TP Sensor Circuit Low Voltage esses 90 DTC P0123 DTC 21 TP Sensor Circuit High Voltage eee 94 DTC P0125 DTC 16 ECT Excessive Time to Closed Loop 98 DTC P0131 DTC 44 HO2S Circuit Low Voltage Bank 1 Sensor 1 102 DTC P0132 DTC 45 HO2S Circuit High Voltage Bank 1 Sensor 1 107 DTC P0134 DTC 42 HO2S Insufficient Activity Bank 1 Sensor 1 113 DTC P0135 DTC 43 HO2S Heater Performance Bank 1 Sensor 1 119 DTC P0151 DTC 64 HO2S Circuit Low Voltage Bank 2 Sensor 1 124 DTC P0152 DTC 65 HO2S Circuit High Voltage Bank 2 Sensor 1 129 DTC P0154 DTC 63 HO2S Insufficient Activity Bank 2 Sensor 1 135 DTC P0155 DTC 62 HO2S Heater Performance Bank 2 Sensor 1 141 DTC P0171 DTC 55 Fuel Trim System Lean sees 146 DTC P0172 DTC 56 Fuel Trim System Rich eese 150 DTC P0336 DTC 41 CKP Sensor Circuit Performance 155 DTC P0500 DTC 24 Vehicle Speed Sensor VSS Circuit 159 DTC P0601 DTC 58 AF ECM Internal Failure REENEN 162 DTC P1215 DTC 27 Control Module Output Circeuits ke EE RENE 164 2002 LPG
41. QUANTUM PROPANE FUEL SYSTEM Engine Speed TACH AF Operation and Vehicle Speed Signal VSS I I I I Wd einpow 033002 jeubis mdyo lOHUOD sen euss Ov uoneredo jeu amp is HOWL 1 UuleJ JleMOd peeds ajolyeA SjonJ sajewayy peeds sulbuy Woo ook bee Ee Be ok meum Ri dm EN es oe En ma ea m jen d LHM INHO AQ ANPON 04102 SSINID pue Sc0S JAJSN D di OL LESZ d38 Lob LHM LHM INO AQ g 009 f 7009 a LHM INYS AQ Lesz Q3 Lek LHM ATE Z009 Sh VLL LE gf Bb W23 JY 3 INPON y SSA Ieubis Ke eubis HOWL jOU0D eufuz paeds epiusA OJy uonejedo peeds eufuz l Jon4 sageuayy SEENEN S EET AROUND e a a a ee aes MC I 2002 LPG G Van Service Manual Supplement Page 16 Website 9 2 03 Connector End Views AF ECM Clear C001 32 Pin Connector End View Connector Part Information e 12129025 e C001 32 Pin Connector Clear Circuit eset Sent eee Idle Control Solenoid Signal Duty Cycle Fuel Control Solenoid Signal Duty Cycle NotUsed OR Assembly Use Only PN L L 925 50 50 450 50 926 32 RED Calibrator Power Assembly Use Only RA ESO EE Bik 490 a ee Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM AF ECM Blue C002 32 Pin Connector End View Connector Part e 12129025 Information e C002 32 Pin Connector Blue Wire Circuit mm coor no rwmen NotUsed s Assembly Use Only 69 Not Used 10 DK GRN R
42. SYSTEM Check for the proper ignition output voltage using the spark tester J26792 or the equivalent Refer to Ignition System Diagnosis in the GM G Van Service Manual Verify that the spark plugs are correct Check the spark plugs Remove the plugs and inspect them for the following conditions Wet plugs Cracks Wear Improper gap Burned electrodes Blistered insulators Heavy deposits Check the spark plug wires by connecting an ohmmeter to the ends of each wire in question If the meter reads over 5 000 ohms replace the wires Note The vehicle may be equipped with low resistance plug wires refer to G Van Service Manual for proper plug wire resistance Additional Checks Important The AF system works on a fumigation principle of fuel introduction and is more sensitive to intake manifold leakage than the gasoline fuel supply system Check for vacuum leaks Vacuum leaks can cause a higher than normal idle and low throttle angle control command Check the Control Module grounds for being clean tight and in their proper locations Check the Automatic Transmission Fluid Pressure TPF manual valve indicator Refer to Transmission Fluid Pressure Switch Assembly Check the scan tool to determine if the Control Module is receiving an A C signal Refer to A C Compressor Clutch Control in the GM G Van Service Manual If a problem exists with the A C ON check the A C system operation Check for EGR being ON while idling that w
43. Sensor Sensor B C B A B LTGRN 432 LT GRN DK BLU 417 ORN BLK 469 020 432 ORN BLK 021 BLK 2761 BLK 2760 BLK 2752 D 469 S019 DK BLU ORN BLK 469 A E Ge i om C005 LT GRN 432 ORN C1 c2 C1 C1 DK BLU 417 pute LT GRN 432 80 de BLU 57 y URED KE Ka BLV 2 24 e RED X 54 BLU 3 C2 RED m 27 Nj 28 Ny 44 d coo2 BLU Sensor Sensor Sensor TP Sensor Sensor MAP Sensor TP Sensor Sensor MAP Sensor 1 Ground Ground Ground Signal Ground Signal Signal Ground Signal Alternative Fuel Engine Control Module AF ECM Conditions for Setting the DTC The AF ECM monitors an IAT sensor signal voltage of less than 0 019 volts for at least 5 seconds continuously Action Taken When the DTC Sets e A first failure of this DTC will NOT illuminate the MIL and will store as Last Test Failed but not as History e The AF EOM will illuminate the MIL and store the DTC as History after TWO consecutive drive trips that the diagnostic runs and fails e The AF ECM will record operating conditions at the time the DTC sets This information will be stored as Freeze Frame data Conditions for Clearing the MIL DTC e The Last Test Failed status will clear when the DTC runs and passes 2002 LPG G Van Service Manual Supplement Page 69 QUANTUM PROPANE FUEL SYSTEM e The AF ECM will turn OFF the MIL after THREE DTCs were stored proceed to the applicable DTC consecutive drive trips that the DTC runs and table in the order stated
44. System OK 2002 LPG G Van Service Manual Supplement Page 42 Website 9 2 03 AF Fuel Control System Diagnosis 1 Dat in Run and Start _ Hot At A Times i H7 ECM 1 F5 LPG Underhood Fuse Fuse Fuse Relay dep 20A G6 20A Center PNK 439 ogN 132 439 133 439 ORN C004 S003 To OEM Components PNK K RED 920 To Fuel 439 orn 1340 O Fuel Sending 012 004 Unit A Ignition Relay 920 BLK 450 001 To Wait To S007 Drive Light and UB LPL DK GRN 903 BLK 450 2 Alternative Fuel I i 1 Ground Engine ES Sig Back of Right Cylinder Head AF EOM Idle Control Solenoid ICS Idle Control Solenoid ICS UH Low Pressure Lock off LPL ignal QUANTUM PROPANE FUEL SYSTEM RED 920 RED 920 S011 005 A Underhood Low Fuel Control DIODE Pressure DIODE Solenoid 2 Ft 3 FCS Solenoid S009 S002 LT BLU 901 LT GRN 911 ed As 3 d C001 CLR Fuel Control Solenoid FCS Solenoid Signal Signal Fuel Control System Components The main components of the fuel control system are e The alternative fuel engine control module AF ECM e The low pressure regulator LPR e The fuel mixer e The fuel control solenoid FCS e The idle control solenoid ICS Fuel Control System Operation The AF ECM receives information from various engine sensors in order to control the fuel and idle control valves to maintain closed loop operation
45. The following PCM replacement procedures must be completed before attempting to operate the vehicle 1 Replace the PCM Refer to PCM Replacement in Engine Controls in the GM G Van service manual Program flash the replacement PCM with the correct LPG software and calibration Is the replacement complete Go to Step 22 H System OK Go to Step 2 2002 LPG G Van Service Manual Supplement Page 118 Reconnect all disconnected or removed components connectors fuses etc Using the scan tool clear the DTC information from BOTH control modules Using the scan tool communicate with both control modules to reset the fuel trim values to zero Operate the vehicle under the Conditions for Running the DTC Using the scan tool parameter DTC STATUS ensure that this DTC runs Did this DTC RUN and PASS Replace the HO2S Refer to HO2S Replacement in the GM G Van service manual Did you complete the repair Go to Step 22 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM DTC P0135 DTC 43 HO2S Heater Performance Bank 1 Sensor 1 3 1 Powertrain Alternative Fuel Control Engine Control Module AF ECM 1 B1S1 Underhood ii Signal Fuse Relay Center B eee P s C001 CLR PPLANHT 1665 PPL WHT TAN WHT Sensor 1 PPLANHT 1665 C004 E Ignition Power HO2S B1S1 Signal Ground Circuit Description The heated oxygen sensor is used to determine the oxygen content of the engine s exhaust The oxyge
46. Using the scan tool establish communication with the PCM 2 Observe the MAP sensor data parameter Does the MAP sensor data parameter indicate MAP voltage less than the specified value 1 Using the scan tool establish communication with the AF ECM 2 Observe the MAP sensor data parameter Does the MAP sensor data parameter indicate MAP voltage greater than the specified value The fault is not present Refer to Diagnostic Aids Go to Go to AF DTC List Are there any DTCs stored that have not been diagnosed DTC P0108 DTC 33 MAP Sensor Circuit High Voltage see Adon TO Vawtg Yes Ne Did you perform the Alternative Fuels AF Powertrain Go to AF On Board Diagnostic OBD System Check Powertrain OBD System heck Go to Step 2 SES 4 8 volts Go to Step 5 Go to Step 3 4 8 volts Go to Step 11 Go to Step 4 Pw Intermittents 1 Disconnect the MAP sensor connector 0 25 volts Go to Step 10 2002 LPG G Van Service Manual Supplement Page 66 Important The PCM MAP sensor data parameter is active only while the engine is running Is the MAP voltage less than the specified value Go to Step 6 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM ation O Vaues ves mo Connect a test light between the sensor ground circuit terminal and battery power Does the test lamp illuminate Go to Step 7 Go to Step 9 1 Connect a DVOM between the 5 volt reference circuit terminal and ground 2 Meas
47. Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM DTC P0113 DTC 25 IAT Sensor Circuit High Voltage Circuit Description The IAT sensor is a thermistor The IAT thermistor has high resistance when cold and low resistance when hot The PCM supplies about 5 volts on the IAT signal circuit The PCM also supplies a ground circuit to the IAT sensor When IAT sensor resistance is high cold sensor the IAT signal voltage remains near the supplied 5 volts As the IAT sensor warms and resistance drops signal voltage is pulled lower to the sensor ground The PCM and the AF ECM monitor the IAT signal circuit voltage to determine the temperature of the air entering the engine The DTC is used to indicate an IAT signal circuit voltage that is above the normal operating range of the sensor This DTC is a type B DTC Website 9 2 03 MM 7 powertrain ioi gx iter Oe ed Alternative Fuel i Control i Engine Control 1 ECT Sensor IAT Sensor 5 Volt 5Volt Module 1 ECT Sensor IAT Sensor 5Volt Module 1 Signal Signal Reference Reference PCM i Signal nal E retorne __ AF ECM 74 C1 BLU 25 C2 RED 8 12 N 197 29 C002 BLU YEL 410 GRY 2704 TAN 472 YEL 410 TAN 472 GRY 2701 YEL 017 410 TAN YEL 410 S018 472 TAN 472 GRY 022 A 2704 GRY 2704 A Engi Intake Ai Coolant Temperature Throttle Men wod Temperature IAT Position Pressure ECT Sensor TP MAP Sensor Sensor Sensor B c A B A B LT GRN 432 LT G
48. air entering the engine The PCM and the AF ECM convert the MAF signal circuit frequency into a grams per second value During low air flow rates such as at engine idle the MAF sensor will produce a low frequency signal around 2 000 Hz or 6 grams per second During high air flow rates such as wide open throttle with load the MAF sensor will produce a high frequency signal around 9000 Hz or 125 grams per second Website 9 2 03 Powertrain Alternative Fuel Sensor Control Sensor Engine Control Signal Module PCM Signal i Module AF ECM C002 BLU MAF S Signal Mass Air Flow MAF Sensor This DTC is used to indicate a MAF sensor frequency that is above the normal operating range of the sensor This DTC is a type A DTC Conditions for Running the DTC Power Up Test e Battery voltage is greater than 10 volts Cranking Test e The engine is cranking but has not yet started e The battery voltage is greater than 8 volts Running High Frequency Test e The engine has been operating for greater than 10 seconds e Battery voltage is greater than 10 volts e Engine speed is greater than 500 RPM Conditions for Setting the DTC All Tests 2002 LPG G Van Service Manual Supplement Page 54 QUANTUM PROPANE FUEL SYSTEM The AF ECM monitors a MAF signal of greater than 10 390 Hz for at least 0 5 seconds continuously Action Taken When the DTC Sets e The AF ECM will illuminate the MIL and stor
49. and not volt reference circuit currently present Refer to Intermittents in Symptom diagnosis for additional information If any additional DTC P0107 DTC 34 MAP Sensor Circuit Low Voltage Sep tion Value amp Did you perform the Alternative Fuels AF Powertrain Go to AF On Board Diagnostic OBD System Check Powertrain OBD System Go to Step 2 SE Important The MAP sensor data parameter is only active while the engine is running 4 Using the scan tool establish communication 0 20 volts with the PCM 5 Observe the MAP sensor data parameter Does the MAP sensor data parameter indicate MAP voltage less than the specified value Go to Step 5 Go to Step 3 4 Using the scan tool establish communication with the AF ECM 5 Observe the MAP sensor data parameter 0 09 volts Does the MAP sensor data parameter indicate MAP voltage less than the specified value Go to Step 13 Go to Step 4 The fault is not present Refer to Diagnostic Aids Are there any DTCs stored that have not been Go to Go to diagnosed AF DTC List Intermittents 2002 LPG G Van Service Manual Supplement Page 62 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Sep Ade Leben Yes No 1 Disconnect the MAP sensor connector 2 Jumper the 5 volt reference circuit terminal to the MAP signal circuit terminal using a 1 amp fused jumper Important 4 8 volts The PCM MAP sensor data parameter is active only while the engine is running 3 Wit
50. battery power ignition power and ground circuits to the PCM Refer to Engine Control Schematics in the GM G Van service manual Verify voltage and or continuity for each circuit Check the Crankshaft Position CKP sensor Check the Camshaft Position CMP sensor Check the Mass Air Flow MAF sensor Fuel System Checks Important A closed LPG manual fuel shut off override valve will create a no start condition Website 9 2 03 Check for air intake system leakage between the mixer and the throttle body Check the fuel pump relay for proper operation The fuel pump relay circuit supplies a voltage signal to the fuel tank lock off solenoid Refer to Fuel Pump Circuit Diagnosis in the GM G Van Service Manual Verify proper operation of the low pressure lock off solenoid Verify proper operation of the fuel tank lock off solenoid Verify proper operation of the fuel control solenoid Verify proper operation of the idle control solenoid Check the fuel system pressures Refer to the AF Fuel System Diagnosis Check the coolant level If coolant is added bleed the cooling system using the Schrader valve on the LPR Check for proper mixer air valve operation 2002 LPG G Van Service Manual Supplement Page 169 Ignition System Checks Engine Mechanical Checks Exhaust System Checks Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Note LPG being a gaseous fuel requires higher secondary ignition system voltages for the equiv
51. being open or for the wrong heat range Refer to Thermostat Diagnosis in Engine Cooling in the GM G Van Service Manual 2002 LPG G Van Service Manual Supplement Page 179 QUANTUM PROPANE FUEL SYSTEM Additional Check Check the transmission shift pattern Refer to the Transmission Controls section in the GM G Van Service Manual Check for Torque Converter Clutch TCC operation Refer to Torque Converter Clutch Solenoid in Automatic Transmission in the GM G Van Service Manual Check for proper calibration of the speedometer Check for dragging brakes 2002 LPG G Van Service Manual Supplement Page 180 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Rough Unstable or Incorrect Idle Stalling DEFINITION The engine runs unevenly at idle If severe enough the engine or vehicle may shake The engine idle speed may vary in RPM Either condition may be severe enough to stall the engine Preliminary Check e Refer to Important Preliminary Checks Sensor Checks e Check for silicon contamination from fuel or improperly used sealant The sensor will have a white powdery coating The sensor will result in a high but false signal voltage rich exhaust indication The Control Module will reduce the amount of fuel delivered to the engine causing a severe driveability problem Check the Heated Oxygen Sensor HO2S performance Check the Engine Coolant Temperature ECT sensor using the scan tool to compare the engine cool
52. circuit breaker Connectors poorly mated Terminals not fully seated in the connector backed out Terminals not properly formed or damaged Terminal to wires poorly connected Terminal tension insufficient Carefully remove all the connector terminals in the problem circuit in order to ensure the proper contact tension If necessary replace all the connector terminals in the problem circuit in order to ensure the proper contact tension Checking for poor terminal to wire connections requires removing the terminal from the connector body in Road Test If a visual and physical check does not locate the cause of the problem drive the vehicle with a J 39200 connected to a suspected circuit or use a scan tool When the problem occurs an abnormal voltage or scan reading indicates the problem may be in that circuit Intermittent Malfunction Indicator The following components can cause intermittent MIL and no DTC s Lamp MIL e A defective relay Control Module driven solenoid or a switch that can cause an electrical system interference Normally the problem will oc cur when the faulty component is operating The improper installation of electrical devices such as lights 2 way radios electric motors etc The ignition secondary voltage shorted to a ground The Malfunction Indicator Lamp MIL circuit or the Diagnostic Test Terminal intermittently shorted to ground The Control Module grounds Loss of DTC Memory In order to che
53. connectors fuses etc Using the scan tool clear the DTC information from BOTH control modules Using the scan tool communicate with both control modules to reset the fuel trim values to zero Operate the vehicle under the Conditions for Running the DTC Using the scan tool parameter DTC STATUS ensure that this DTC runs Repair the possible causes of lean engine operation Refer to the items in Step 4 Is the repair Go to Step 12 Did this DTC RUN and PASS Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM DTC P0172 DTC 56 Fuel Trim System Rich Circuit Description The heated oxygen sensor is used to determine the oxygen content of the engine s exhaust The oxygen content indicates when the engine is operating lean or rich When the engine is operating lean the exhaust will have more oxygen content Once at operating temperature the HO2S will produce a voltage in relation to the oxygen content of the exhaust The HO2S requires an operating temperature of 600 F 360 C to produce voltage The HO2S will produce more voltage when the exhaust is rich and less voltage when the exhaust is lean The HO2S operating range is around 0 10 volts 100 mV to 1 volt 1000 mV The AF ECM utilizes a closed loop fuel air fuel metering system when the HO2S is at operating temperature During normal closed loop operation the AF ECM will add fuel richen the mixture when the HO2S indicates a lean exhaust The AF ECM will remo
54. help identify the problem Check the coolant level If coolant is added bleed the cooling system using the Schrader valve on the LPR Check the fuel pressure while the condition exists Refer to AF Fuel System Diagnosis Verify proper fuel control solenoid operation Verify that the LPG manual shut off valve is fully open Check the in line fuel filter for restrictions Ignition System Checks Check for the proper ignition output voltage using the spark tester J26792 or the equivalent Refer to Enhanced Ignition System in the GM G Van Service Manual Verify that the spark plugs are correct Check the spark plugs Remove the plugs and inspect them for the following conditions Wet plugs Cracks Wear Improper gap Burned electrodes Heavy deposits Check the Crankshaft Position CKP sensor Refer to DTC P0336 CKP Sensor Circuit Performance in the GM G Van Service Manual Additional Check Check the Control Module grounds for being clean tight and in their proper locations Check the generator output voltage Check the vacuum hoses for kinks or leaks Refer to the Vehicle Emission Control Information label on the top of the radiator Check for an Intermittent EGR problem Refer to EGR System Diagnosis in the GM G Van Service Manual Check for Torque Converter Clutch TCC operation 2002 LPG G Van Service Manual Supplement Page 183 Website 9 2 03 REPAIR INSTRUCTIONS PROPANE FUEL SYSTEM PRESSURE RELIEF CA
55. in the OBD System Check passes e The History status will clear after FORTY Test Description consecutive WARM UP cycles with NO failures The numbers below refer to the step numbers on the of ANY DTC diagnostic table e All information can be cleared using a scan tool 2 This step determines if the failure condition is e Interruption of Control Module AF ECM PCM present power and ground MAY clear DTC information 5 This step determines of the IAT sensor is Clearing DTC information with this method is shorted inconsistent and should not be performed 6 This step determines if a short is present in the wiring harness Diagnostic Aids 7 This step determines if the PCM or the AF ECM is the cause of the shorted condition Fault Not Present 8 This step determines if an open circuit condition Fault Not Present indicates the condition that is present between the PCM and the AF caused the DTC to set is intermittent and not connecter C005 currently present Refer to Intermittents in Symptom diagnosis for additional information If any additional DTC P0112 DTC 23 IAT Sensor Circuit Low Voltage Sep aon va Ye We Did you perform the Alternative Fuels AF Powertrain Go to AF On Board Diagnostic OBD System Check Powertrain OBD System 2 Go to Step Check 1 Using the scan tool establish communication with the AF ECM 2 Observe the IAT sensor data parameter 0 019 volts Does the IAT sensor data parameter in
56. mixture A negative percentage value indicates fuel is being removed form the mixture This DTC is used to indicate a fully rich fuel trim system that cannot compensate for a lean engine exhaust content This DTC is a type B DTC Conditions for Running the DTC e The engine coolant temperature is greater than 185 F 85 C e The AF ECM is operating in closed loop fuel control Conditions for Setting the DTC The AF ECM monitors that the short term fuel trim is at 100 percent or long term fuel trim is at 50 percent for at least 5 seconds continuously Action Taken When the DTC Sets e A first failure of this DTC will NOT illuminate the MIL and will store as Last Test Failed but not as History Website 9 2 03 e The AF ECM will illuminate the MIL and store the DTC as History TWO consecutive drive trips that the diagnostic runs and fails e The AF ECM will record operating conditions at the time the DTC sets This information will be stored as Freeze Frame data Conditions for Clearing the MIL DTC e The Last Test Failed status will clear when the DTC runs and passes e The AF ECM will turn OFF the MIL after THREE consecutive drive trips that the DTC runs and passes e The History status will clear after FORTY consecutive WARM UP cycles with NO failures of ANY DTC e All information can be cleared using a scan tool e Interruption of Control Module AF ECM PCM power and ground MAY clear DTC information Clearing
57. not set supplies about 5 volts on the ECT signal circuit The e This DTC has not tested this ignition cycle PCM also supplies a ground circuit to the ECT e The engine has been operating for greater than sensor When ECT resistance is high cold sensor 8 5 minutes ur art SR E re the supplied 5 e The vehicle speed is greater than 5 MPH volts As the sensor warms and resistance e Intake air temperature is greater than 5 F drops signal voltage is pulled lower to the sensor 15 C ground The PCM and the AF ECM monitor the ECT signal circuit voltage to determine engine temperature This DTC is used to indicate an engine coolant temperature that is less than the temperature necessary to enable AF ECM closed loop fuel control This DTC is a type A DTC The AF ECM monitors an engine coolant temperature that has NOT increased above the start up temperature by 25 C e The engine coolant temperature at engine start up is between 1 F 17 C and 91 F 33 C Conditions for Setting the DTC 2002 LPG G Van Service Manual Supplement Page 98 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Action Taken When the DTC Sets The AF ECM will illuminate the MIL and store the DTC as History after ONE drive trip that the diagnostic runs and fails The AF ECM will record operating conditions at the time the DTC sets This information will be stored as Freeze Frame data Conditions for Clearing the MIL DTC Step Action Value s
58. operating 78 mV Go to Step 5 Go to Step 3 temperature is reached Using a scan tool establish communication with 2002 LPG G Van Service Manual Supplement Page 125 the AF ECM Using a scan tool monitor the AF ECM HO2S B2 S1 voltage Is the HO2S voltage fixed less than the value specified Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM value s Yes Ne The condition that set this DTC is not present This DTC may have been set by one of the following conditions A signal wire intermittently shorted to engine ground or to the HO2S low circuit An open between the engine harness circuit splice and the AF ECM connectors HO2S connector water intrusion An exhaust leak between the HO2S and the engine An intermittent lean condition such as the following Vacuum leaks Restricted fuel filter Low fuel pressure Lean condition at LPR Lean condition at fuel mixer Lean condition at FCS Lean condition at ICS An inaccurate MAF sensor Repair any of the above conditions as necessary Was a condition found and repaired Go to Step 16 Go to Step 4 The fault is not present Refer to Diagnostic Aids Are there any DTCs stored that have not been diagnosed Goto oop l AF DTC List Intermittents Run the engine until normal operating temperature is reached Using the scan tool establish communication with the PCM Using a scan tool monitor the HO2S B2 S1 voltage Is the HO2S voltage fixed less that the
59. pressure i reading for the LPR primary pressure Is the fuel pressure ABOVE the specified value Go to Step 26 Go to Step 13 Turn OFF the ignition Disconnect the underhood LPL connector Install a test light between the pins of the LPL connector Crank the engine The test light should illuminate Does the test light illuminate Go to Step 14 Go to Step 16 Using a DVOM check the resistance of the underhood low pressure lock off LPL 122 160 Is the resistance within the specified range Go to Step 15 Go to Step 27 Was a problem found and repaired 1 Remove the mixer and elbow assembly 2 Remove the mixer cover and check the air valve for sticking binding or foreign debris 2002 LPG G Van Service Manual Supplement Page 39 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Sep on Valet Yes No 1 Turn the ignition OFF 2 Close the manual shut off override valve on the LPG fuel tank lock off solenoid CAUTION When disconnecting LPG fuel lines liquid LPG may be present Perform this step in a well ventilated area 3 Loosen the fuel inlet hose fitting at the inlet of the underhood LPL Was fuel present when the fitting was loosened ONO IED ez PONE Disconnect the fuel tank lock off connector Install a test light between the pins of the LPL connector Turn the ignition ON The test light should illuminate for 2 seconds 1 Turn OFF the ignition 2 Connect the test light to chassi
60. the exhaust will have more oxygen content Once at operating temperature the HO2S will produce a voltage in relation to the oxygen content of the exhaust The HO2S requires an operating temperature of 600 F 360 C to produce voltage The HO2S will produce more voltage when the exhaust is rich and less voltage when the exhaust is lean The HO2S operating range is around 0 10 volts 100 mV to 1 volt 1000 mV The PCM supplies a bias or reference voltage to the HO2S This bias voltage is around 450 mV This DTC is used to indicate an HO2S signal voltage that is below the normal operating range of the sensor This DTC is a type B DTC Conditions for Running the DTC e Engine speed is greater than 400 RPM Website 9 2 03 moe oe oe E i Powertrain Control Module PCM See E El Ho2s Joss Alternative Fuel H 1 B281 B2 1 1 Engine Control Signal ow bee vin ee eee g ee C001 CLR C004 1666 TAN d TAN C004 Heated Oxygen Sensor HO2S Bank 2 Sensor 1 e Engine coolant temperature is greater than 160 F 70 C e The oxygen sensor has been at operating temperature for at least 30 seconds The engine coolant temperature must be greater than 50 C AND the mass air flow above 4 4 gms sec for at least 30 seconds for the AF ECM to determine the HO2S is at operating temperature e The AF ECM is operating in closed loop fuel control Conditions for Setting the DTC The AF ECM m
61. the AF ECM and the PCM for stored DTCs Go to AF Powertrain Does the vehicle operate normally with no stored OBD System DTCs System OK Check 2002 LPG G Van Service Manual Supplement Page 36 Website 9 2 03 AF Fuel System Diagnosis Secondary Pressure Test Port f QUANTUM PROPANE FUEL SYSTEM Primary Pressure Test Port Fuel System Description The alternative fuel engine control module AF ECM receives information from various engine sensors in order to control the operation of the fuel and idle control valves and the underhood low pressure lock off LPL solenoid The fuel tank lock off and underhood LPL solenoids prevent fuel flow unless the engine is cranking or running LPG is stored in the tank and delivered under pressure to the system as a liquid During key ON the fuel tank lock off receives a two 2 second prime pulse from the OEM fuel pump circuit LPG flows from the tank through the fuel filter and fuel lines at pressures up to 312 psi to the underhood LPL When the engine is cranking or running both lock offs open and LPG flows into the low pressure regulator LPR where the fuel is vaporized and the pressure reduced in two stages The first stage reduces the pressure to approximately 2 5 psi The second stage reduces the pressure to approximately negative 1 8 of water column A vacuum generated by air flowing through the mixer then draws the fuel from the secondary chamber of the
62. the DTC as History after TWO consecutive drive trips that the diagnostic runs and fails The AF ECM will record operating conditions at the time the DTC sets This information will be stored as Freeze Frame data Conditions for Clearing the MIL DTC The Last Test Failed status will clear when the DTC runs and passes The AF ECM will turn OFF the MIL after THREE consecutive drip trips that the DTC runs and passes The history status will clear after FORTY consecutive warm up cycles with no failures of any DTC All DTC information can be cleared using a scan tool Interruption of AF ECM or PCM power or ground may clear DTC information Clearing DTC information with this method is inconsistent and should not be performed Diagnostic Aids Fault Not Present Fault Not Present indicates the condition that caused the DTC to set is intermittent and not currently present Refer to Intermittents in Symptom diagnosis for additional information If any additional DTCs were stored proceed to the applicable DTC table in the order stated in the OBD System Check Test Description The numbers below refer to the step numbers on the diagnostic table 2 This step determines if the failure condition affects the gasoline control module 3 This step determines if the failure condition is present 5 This step determines if the IAT sensor is the open condition 6 This step determines if the sensor ground circuit is the open condition
63. the HO2S will produce a voltage in relation to the oxygen content of the exhaust The HO2S requires an operating temperature of 600 F 360 C to produce voltage The HO2S will produce more voltage when the exhaust is rich and less voltage when the exhaust is lean The HO2S operating range is around 0 10 volts 100 mV to 1 volt 1000 mV The PCM supplies a bias or reference voltage to the HO2S This bias voltage is around 450 mV This DTC is used to indicate an HO2S signal voltage that is above the normal operating range of the sensor This DTC is a type B DTC Conditions for Running the DTC e Engine speed is greater than 400 RPM Website 9 2 03 4 i Alternative Fuel B28 1 Engine Control Signal Module AF ECM be 4 3 C001 CLR Powertrain 1 Control Module PCM 1 HO2S C1 BLU 1667 C004 TAN C004 Heated Oxygen Sensor HO2S Bank 2 Sensor 1 B281 e Engine coolant temperature is greater than 160 F 70 C e The oxygen sensor has been at operating temperature for at least 30 seconds The engine coolant temperature must be greater than 50 C AND the mass air flow above 4 4 gms sec for at least 30 seconds for the AF ECM to determine the HO2S is at operating temperature e The AF ECM is operating in closed loop fuel control Conditions for Setting the DTC The AF ECM monitors an HO2S signal voltage of greater than 1 0 volt 1
64. to NFPA 58 for more information FUEL TANK LOCK OFF REPLACEMENT Removal Procedure 1 Relieve the propane fuel system pressure Refer to Propane Fuel System Pressure Relief 2 Disconnect the negative battery cable 3 Remove the fuel tank cover bolts and the cover CAUTION The propane fuel tank contains liquid and vaporous propane at pressures up to 312 psi Failure to drain the tank before service may cause fire and or personal injury 4 Drain the propane fuel tank Refer to Propane Fuel Tank Draining 5 Disconnect the fuel tank lock off electrical connector 6 Disconnect the fuel line from the fuel tank lock off 7 Remove the fuel tank lock off from the tank Installation Procedure Important e Do not use Teflon tape on any fuel fitting Use liquid pipe thread sealant 1 Apply liquid pipe thread sealant to the fuel tank lock off fitting 2 Install the lock off in the tank e Tighten to 2 3 TFFT 3 Connect the fuel line to the fuel tank lock off e Tighten to 37 Nem 27 lb ft 4 Connect the fuel tank lock off electrical connector Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Connect the negative battery cable Fill the propane fuel tank Start the vehicle and leak check the propane fuel system at each serviced fitting 8 Install the fuel tank cover and bolts NOOO FUEL SENDING UNIT REPLACEMENT Removal Procedure 1 Remove the propane fuel tank Refer to Propane Fuel Tank Replaceme
65. with the PCM 3 Observe the TP sensor data parameter 4 Fully depress the accelerator pedal Does the TP sensor data parameter indicate TP voltage greater than the specified value 1 Using the scan tool establish communication with the AF ECM 2 Observe the TP sensor data parameter Does the TP sensor data parameter indicate TP voltage less than the specified value Open and close the throttle while observing the TP sensor data parameter Does the TP sensor data parameter ever indicate TP voltage greater than the specified value Website 9 2 03 Value s Ye m Go to AF Powertrain OBD System Go to Step 2 Check 4 9 volts Go to Step 6 Go to Step 3 Go to Step 12 Go to Step 4 Go to Step 6 Go to Step 5 2002 LPG G Van Service Manual Supplement Page 95 4 9 volts 4 9 volts QUANTUM PROPANE FUEL SYSTEM Value s The fault is not present Refer to Diagnostic Aids Go to Go to AF DTC List Intermittents Go to Step 7 Goto Step 11 Go to Step 8 Go to Step 10 Go to Step 15 Go to Step 9 Go to Step 18 Go to Step 16 Go to Step 18 Go to Step 16 Go to Step 18 Go to Step 16 2002 LPG G Van Service Manual Supplement Page 96 Are there any DTCs stored that have not been diagnosed 1 Disconnect the TP sensor connector 2 Observe the TP sensor data parameter 0 75 volts Does the TP sensor data parameter indicate TP voltage greater than the specified value Connect an unpowere
66. 0 mV for the AF ECM to determine the HO2S was cold Conditions for Setting the DTC The AF ECM monitors an HO2S signal voltage that did not leave the cold sensor bias voltage range of 0 30 volts 300 mV to 0 060 volts 600 mV in an acceptable amount of time The time varies from 50 seconds to 110 seconds based upon mass air flow Action Taken When the DTC Sets e A first failure of this DTC will NOT illuminate the MIL and will store as Last Test Failed but not as History e The AF ECM will illuminate the MIL and store the DTC as History TWO consecutive drive trips that the diagnostic runs and fails e The AF ECM will record operating conditions at the time the DTC sets This information will be stored as Freeze Frame data Conditions for Clearing the MIL DTC e The Last Test Failed status will clear when the DTC runs and passes e The AF ECM will turn OFF the MIL after THREE consecutive drive trips that the DTC runs and passes e The History status will clear after FORTY consecutive WARM UP cycles with NO failures of ANY DTC e All information can be cleared using a scan tool e Interruption of Control Module AF ECM PCM power and ground MAY clear DTC information Clearing DTC information with this method is inconsistent and should not be performed Diagnostic Aids Check for the following condition e Low or empty LPG fuel tank For proper LPG fuel system operation liquid fuel is required at the LPR inlet If the
67. 000 mV for 5 seconds continuously Action Taken When the DTC Sets The AF ECM will control fuel trim based upon the Bank 1 Sensor 1 signal If a Bank 1 Sensor 1 DTC sets the AF ECM will operate in open loop fuel control 2002 LPG G Van Service Manual Supplement Page 129 e A first failure of this DTC will NOT illuminate the MIL and will store as Last Test Failed but not as History e The AF ECM will illuminate the MIL and store the DTC as History TWO consecutive drive trips that the diagnostic runs and fails e The AF ECM will record operating conditions at the time the DTC sets This information will be stored as Freeze Frame data Conditions for Clearing the MIL DTC e The Last Test Failed status will clear when the DTC runs and passes e The AF ECM will turn OFF the MIL after THREE consecutive drive trips that the DTC runs and passes e The History status will clear after FORTY consecutive WARM UP cycles with NO failures of ANY DTC e All information can be cleared using a scan tool e Interruption of Control Module AF ECM PCM power and ground MAY clear DTC information Clearing DTC information with this method is inconsistent and should not be performed Diagnostic Aids Fault Not Present Fault Not Present indicates the condition that caused the DTC to set is intermittent and not currently present Refer to ntermittents in Symptom diagnosis for additional information If any additional DTCs were stor
68. 02 LPG G Van Service Manual Supplement Page 30 QUANTUM PROPANE FUEL SYSTEM 6 This step checks if a PCM system failure is the 8 This step tests for an open MIL Input circuit The cause of the inoperative MIL and a no start is a PCM should always command the MIL ON when loss of voltage to the PCM the ignition is ON and the engine is OFF 9 This step test for an open MIL Control circuit or IP Malfunction Indicator Lamp Circuit sep an O O S Va Yes No Did you perform the Alternative Fuels AF Powertrain Go to AF On Board Diagnostic OBD System Check Powertrain OBD System Go to Step 2 Chack Go to Step 3 Go to Step 6 Go to Step 5 Go to Step 4 Go to AF Powertrain OBD System Go to Check Turn ON the ignition with the engine OFF Is the he MIL continuously illuminated 1 Connect a scan tool 2 While communicating with the AF ECM command the MIL OFF Is the MIL illuminated The fault is not present Refer to Diagnostic Aids Intermittents Go to Step 12 Go to Step 11 Is an operational concern still present Observe the MIL input PCM data parameter on the scan tool with the MIL commanded OFF Is a PCM MIL input request present Observe the operation of the other instrument panel IP gauges and or lamps Do all the IP indicators except the MIL operate correctly Go to Step 8 Go to Step 16 Go to Step 9 Go to Step 14 Go to Step 17 Goto Step 13 2002 LPG G Van Service Manual Supplemen
69. 1 6008 priouejos Qd 40 4901 eInsseig M01 Doouepun LLOS 026 038 so prouajos O4JUOD IPI v voos oz6 GAY W93 4v Gen peay sepunAo WD Jo yoeg punolg jeubig jomuog uug Joie e jen engedi 4 osr 41g 06 NYS AQ 1d1 an pue 14617 eAug 2400S OL HEM OL Loos 18 0Z6 Aejay uoniubI yun Buipues feng oL sjuauoduo WO OL fei Aejay asn4 pooysapun L SOWIE yY PH Li L 2002 LPG G Van Service Manual Supplement Page 10 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Fuel Tank Lock off Solenoid and Fuel Sending Uni 1 Nd aNpow pesH Jepun Ao W I Jo 4693 punos I jonuo2 BOUaIBJOY M01 y VIENISMOd osr Lag a N Aejay uoniuf ES pue 34617 e ug 0 EAA OL sjusuoduloo IN3O OL prouajos 30010 40 4901 Xue any Aey uoniuD oL sjuauoduloo WO OL LOED OL L t LHMWr T8 sjusuodwoy Jejue i WO OL Ae aen i poowapun i L sjueuoduio53 ory OAS opp i hi s usuodu0g nao OL S9 Nao ya IT H Jejua2 1 re ira gcc Od einpow Jejue2 Apel esny i 19000 Aejay esnJ poouiepun 1 ui amp ewog pooujepur 2002 LPG G Van Service Manual Supplement Page 11 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Engine Coolant Temperature ECT Intake Air Temperature IAT Throttle Position TP and Manifold Absolute Pressure Sensors WO 3v 3 NPON jo3uo2 euibu3 en eAgeuireyv V DU D eubig D WOd einp
70. 10 volts e Engine speed is greater than 500 RPM Conditions for Setting the DTC Cranking Test e The AF ECM monitors the MAF sensor signal of less than 125 Hz 0 gms sec for at least 0 5 seconds continuously 2002 LPG G Van Service Manual Supplement Page 50 QUANTUM PROPANE FUEL SYSTEM Running Test e The AF ECM monitors a MAF sensor signal of less than 1500 Hz 2 5 gms sec for al least 0 5 seconds continuously Action Taken When the DTC Sets e The AF ECM will illuminate the MIL and store the DTC as History during ONE drive trip in which the diagnostic runs and fails e The AF ECM will record operating conditions at the time the DTC sets This information will be stored as Freeze Frame data Conditions for Clearing the MIL DTC e The Last Test Failed status will clear when the DTC runs and passes e The AF EOM will turn OFF the MIL after THREE consecutive drive trips that the DTC runs and passes e The History status will clear after FORTY consecutive WARM UP cycles with NO failures of ANY DTC e All information can be cleared using a scan tool e Interruption of Control Module AF ECM PCM power and ground MAY clear DTC information Clearing DTC information with this method is inconsistent and should not be performed Diagnostic Aids Fault Not Present Fault Not Present indicates the condition that caused the DTC to set is intermittent and not currently present Refer to Intermittents in Symptom d
71. 16 Go to Step 13 Replace the HO2S sensor Refer to Heated Oxygen Sensor HO2S Replacement in the GM G Van service manual Is the action complete pole Step TE Repair the open HO2S heater ground circuit Is the action complete Go to Step 18 1 Repair the lack of power on the HO2S heater ignition feed circuit If the fuse is open repair the short to ground on the circuit An open fuse or lack of power to the fuse may cause other DTCs or symptoms to be present Is the action complete Go to Step 18 Repair the circuit that measured high resistance Is the action complete Go to Step 18 2002 LPG G Van Service Manual Supplement Page 122 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Value s ves mo Inspect the HO2S sensor signal and low circuit for continuity between the AF ECM connector terminals and the HO2S connector terminals Inspect these circuits for shorts to other circuits or to ground Ensure the oxygen sensor gasoline control module and the AF ECM connectors are disconnected before testing circuits 3 Repair the wiring as necessary Was a problem found Go to Step 18 Go to Step 15 Replace the AF ECM Refer to AF ECM Replacement Is the replacement complete Go to Step 18 1 Inspect for proper PCM terminal contact 2 Repair the terminals as necessary Was a problem found and repaired Go to Step 18 Goto Step 17 Important The following PCM replacement procedures must be completed
72. 171 DTC 55 Fuel Trim System Lean Circuit Description The heated oxygen sensor is used to determine the oxygen content of the engine s exhaust The oxygen content indicates when the engine is operating lean or rich When the engine is operating lean the exhaust will have more oxygen content Once at operating temperature the HO2S will produce a voltage in relation to the oxygen content of the exhaust The HO2S requires an operating temperature of 600 F 360 C to produce voltage The HO2S will produce more voltage when the exhaust is rich and less voltage when the exhaust is lean The HO2S operating range is around 0 10 volts 100 mV to 1 volt 1000 mV The AF ECM utilizes a closed loop fuel air fuel metering system when the HO2S is at operating temperature During normal closed loop operation the AF ECM will add fuel richen the mixture when the HO2S indicates a lean exhaust The AF ECM will remove fuel lean the mixture when the HO2S indicates a rich exhaust This addition and removal to the air fuel mixture is indicated on the scan tool as the long and short term fuel trim values Short term fuel trim values are adjustments to the air fuel mixture that occur quickly Long term values are adjustments to the air fuel mixture that accumulate over longer periods of time The long and short term fuel trim values are displayed on a scan tool as both percent and counts A positive percentage value indicates fuel is being added to the
73. 2 Sensor 1 Sep Aon Veit Ye We Did you perform the Alternative Fuels AF Powertrain On Board Diagnostic OBD System Check Use a scan tool to establish communication with the AF ECM Capture the DTC information from the AF ECM in the scan tool Clear the DTC information using the scan tool Reset the fuel trim values Start and idle the engine until normal operating temperature is reached Use the scan tool to monitor the HO2S B2 S1 voltage Is the voltage fixed within the specified range The condition that set this DTC is not present This DTC may have been set by one of the following conditions Water intrusion of the HO2S connector An intermittently open HO2S high signal circuit An intermittently open HO2S low circuit An HO2S low circuit with high resistance to ground Any AF ECM ground circuits with high resistance to ground An inoperative HO2S heater A faulty HO2S or PCM terminal contact An exhaust system leak typically within 12 inches upstream of the HO2S A defective HO2S Repair any of the above conditions as necessary Was a condition found and repaired The fault is not present Refer to Diagnostic Aids Are any DTOs stored that have not been diagnosed Website 9 2 03 ER Go to Step 2 i Go to Step 22 Go to Step 4 Go to AF Powertrain OBD System Check Go to Step 3 0 1 to 1 0 volts Go to Step 5 Go to Intermittents Go to AF DTC List 2002 L
74. 22 Go to Step 20 Was a wire repair made Replace the AF ECM Refer to AF ECM Replacement Is the replacement complete Perform the AF Fuel System diagnosis and return to this step Refer to AF Fuel System Diagnosis Was an LPG fuel system problem found and repaired Important The following PCM replacement procedures must be completed before attempting to operate the vehicle 1 Replace the PCM Refer to PCM Replacement in Engine Controls in the GM G Van service manual Program flash the replacement PCM with the correct LPG software and calibration Is the replacement complete Go to Step 22 H System OK Go to Step 2 2002 LPG G Van Service Manual Supplement Page 140 Reconnect all disconnected or removed components connectors fuses etc Using the scan tool clear the DTC information from BOTH control modules Using the scan tool communicate with both control modules to reset the fuel trim values to zero Operate the vehicle under the Conditions for Running the DTC Using the scan tool parameter DTC STATUS ensure that this DTC runs Did this DTC RUN and PASS Replace the HO2S Refer to HO2S Replacement in the GM G Van service manual Did you complete the repair Go to Step 22 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM DTC P0155 DTC 62 HO2S Heater Performance Bank 2 Sensor 1 Hot in Run And Start T Q S o Underhood Fuse Relay r HO2S Bank 1 4
75. 3 QUANTUM PROPANE FUEL SYSTEM DTC P0123 DTC 21 Throttle Position TP Sensor Circuit High Voltage Powertrain Control Module PCM Circuit Description The throttle position TP sensor is a potentiometer The PCM supplies about 5 volts on the TP sensor reference voltage circuit The PCM also supplies a ground circuit to the TP sensor When the throttle is pressed the TP signal voltage rises to near the supplied 5 volts As the throttle is released the TP signal voltage drops to around 0 6 volts The PCM and the AF ECM monitor the TP signal circuit voltage and determine the angle or opening of the throttle blade This DTC is used to indicate a TP signal voltage that is above the normal operating range of the sensor This is a type B DTC Website 9 2 03 Tica wag gad Camo e ME 7 powertrain ici Ng Gites PITE td Alternative Fuel i Control i Engine Control 1 ECT Sensor IAT Sensor 5 Volt 5 Volt Module f ECT Sensor IAT Sensor 5 Volt Module GE darla e mom ce Reference PCM bol Signal Signal Reference AF ECM 74 C1 BLU 25 NN C2 RED 8 48 C1 BLU IRAN 180 29 C002 BLU YEL 410 GRY 2704 TAI 2 YEL 410 TAN 472 GRY 2701 A B D YEL 017 410 TAN YEL 410 S018 472 TAN 472 GRY 022 A 2704 GRY 2704 A Engi Intake Ai Coolant Temperature Throttle Manro Temperature IAT Position ECT Sensor TP ea Se SE Sensor Sensor B c A B A B LTGRN 432 LT GRN DK BLU 417 ORN BLK
76. ANTUM PROPANE FUEL SYSTEM that fuel vapor is delivered to the LPR inlet the air fuel mixture will be lean and the MIL may illuminate Also the vehicle will start and idle normally but hesitate and stumble under load If the DTC is current verify that the fuel tank is at least Y full If the DTC is stored in history verify with the operator if the vehicle has recently been run low or out of fuel Fault Not Present Fault Not Present indicates the condition that caused the DTC to set is intermittent and not currently present Refer to Intermittents in Symptom diagnosis for additional information If any additional DTCs were stored proceed to the applicable DTC table in the order stated in the OBD System Check Preliminary Checks e A heated oxygen sensor wire A sensor pigtail may be mis routed and contacting the exhaust manifold e An intermittent ground in the wire between the connector and the sensor e A poor ECM to the engine block ground e fthe above check out okay the problem may be a faulty heated sensor Never solder the HO2S wires For proper wire and connector repair refer to Wiring Repairs in Engine Electrical in the appropriate GM G Van Service Manual DTC P0151 DTC 64 HO2S Circuit Low Voltage Bank 2 Sensor 1 aer feier Vaws ves Ne Was the Alternative Fuels AF Powertrain On Board Diagnostic OBD System Check performed Go to AF Powertrain BD Go to Step 2 o dud Run the engine until normal
77. AT Sensor 5 Volt 5Volt 1 Module f ECT Sensor IAT Sensor 5 Volt Module 1 Signal Signal Reference Reference PCM 1 Vi EE Signal D Zens __ AF ECM 74 C1 BLU 25 C2 RED 8 48 C1 BLU 12 N 13 29 C002 BLU YEL 410 GRY 2704 TAN 472 YEL 410 TAN 472 GRY 2701 A B D YEL 017 410 TAN YEL 410 S018 472 TAN 472 GRY 022 A 2704 GRY 2704 A C Engi Intake Ai ee Temperature Throttle Men wod Sensor E Pressure TP MAP Sensor Sensor A B A B LTGRN 432 LT GRN DK BLU 417 ORN BLK 469 020 ORN BLK 021 BLK 2761 BLK 2760 BLK 2752 D 469 S019 DK BLU ORN BLK 469 A S E DK BLU 417 s y C005 LT GRN 432 ORN C1 c2 C1 C1 pk BLU 417 P rend 432 ni A alen sey come ale elen my omen i Sensor Sensor Sensor TP Sensor Sensor MAP Sensor 4 i TP Sensor Sensor MAP Sensor 1 l Ground Ground Ground Signal Ground Signal 1 Signal Ground Signal 1 1 GE E Powertrain Control Module PCM Alternative Fuel Engine Control Module AF ECM No AF ECM DTOs are set e The TP sensor angle is less that 70 percent Conditions for Setting the DTC The AF ECM monitors that the MAP sensor pressure changes less that 6 kPa when the TP sensor angle changes by greater that 20 percent Action Taken When the DTC Sets The AF ECM will illuminate the MIL and store the DTC as History during ONE drive trip that the diagnostic runs and fails The AF ECM will record operating conditions at the time the DTC set
78. F Powertrain On Board Diagnostic OBD System Check Go to AF Powertrain OBD System Check Go to Step 2 i Website 9 2 03 2002 LPG G Van Service Manual Supplement Page 142 QUANTUM PROPANE FUEL SYSTEM Sep Aeon O va Ye No 7 Important The HO2S must be cool before proceeding with this diagnosis The ignition must remain OFF for at least on half hour before proceeding with the diagnosis 1 Connect a scan tool 2 Set up the scan tool with the proper vehicle identification prior to turning the ignition ON Establish communication with the PCM 150 mV Turn the ignition ON leaving the engine OFF and as quickly as possible observe and record the HO2S voltage for the sensor that applies to this DTC Observe the HO2S voltage for two minutes Does the HO2S voltage increase or decrease from the initial voltage by at least the specified value Go to Step 3 Go to Step 6 Allow the HO2S voltage to stabilize Use the scan tool to observe and record the current HO2S voltage from the PCM Use the scan tool to establish communication with the AF ECM 45 mV Use the scan tool to observe and record the current voltage from the AF ECM for the HO2S B2 S1 Does the AF ECM indicate the same HO2S voltage as the PCM plus or minus the specified value Go to Step 4 Go to Step 14 Go to Step 18 Go to Step 5 Go to Go to AF DTC List Intermittents Go to Step 7 Go to Step 8 2002 LPG G Van Service Manual Sup
79. GM G Van Service Manual 2002 LPG G Van Service Manual Supplement Page 177 Website 9 2 03 Additional Check Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Check the Control Module grounds for being clean tight and in their proper locations Check for an Intermittent EGR problem Refer to EGR System Diagnosis in the GM G Van Service Manual Check the A C operation Refer to A C Compressor Clutch Control Diagnosis in the GM G Van Service Manual Check for proper Torque Converter Clutch TCC operation Check the generator output voltage If all procedures have been completed and no malfunction has been found review and inspect the following items Visually and physically inspect all electrical connections within the suspected circuit and or systems Check the scan tool data 2002 LPG G Van Service Manual Supplement Page 178 QUANTUM PROPANE FUEL SYSTEM Poor Fuel Economy ms D O DEFINITION Fuel economy as measured by an actual road test is noticeably lower than expected Also the economy is noticeably lower than it was on this vehicle at one time as previously shown by an actual road test Preliminary Checks Sensor Checks Ignition System Checks Cooling System Checks Website 9 2 03 Refer to Important Preliminary Checks Check the air cleaner element filter for dirt or being plugged Visually Physically check the vacuum hoses for splits kinks and proper connections as show
80. Important Preliminary Checks Before Using This Section Before using this section you should have performed AF Powertrain On Board Diagnostic Check and determined that 1 The Control Module and MIL Malfunction Indicator Lamp are operating correctly 2 There are no Diagnostic Trouble Codes DTCs stored ora DTC exists but without a MIL Several of the following symptom procedures call for a careful visual and physical check The visual and physical checks are very important The checks can lead to correcting a problem without further checks that may save valuable time LPG Fuel System Check Verify the customer complaint Locate the correct symptom table Check the items indicated under that symptom Operate the vehicle under the conditions the symptom occurs Verify HO2S switching between lean and rich IMPORTANT Normal HO2S switching indicates the LPG fuel system is in closed loop and operating correctly at that time If a scan tool is available take a snapshot under the condition that the symptom occurs Go to AF Engine Scan Tool Data List to verify normal sensor values and parameters Visual and Physical Checks Check all ECM and PCM system fuses and circuit breakers Check the ECM and PCM grounds for being clean tight and in their proper location Check the vacuum hoses for splits kinks and proper connections as shown on the Vehicle Emission Control Information Label Check thoroughly for any type of leak or r
81. L SYSTEM PROPANE FUEL TANK COVER REPLACEMENT Removal Procedure 1 Remove the propane fuel tank cover mounting bolts and the cover Installation Procedure 1 Install the propane fuel tank cover and the mounting bolts e Tighten the bolts to 22 Nem 16 ft lb 2002 LPG G Van Service Manual Supplement Page 185 Fuel In From Fill Valve Liquid Level Gauge 80 Fill QUANTUM PROPANE FUEL SYSTEM Pressure Relief Device PRD Fuel Tank Lock off Fuel Out Fuel Sending Unit FSU PROPANE FUEL TANK REPLACEMENT Removal Procedure f co D Relieve the propane fuel system pressure Refer to Propane Fuel System Pressure Relief Disconnect the negative battery cable Remove the fuel tank cover mounting bolts and cover Disconnect the following electrical connectors e Fuel sending unit FSU e Fueltank lock off Disconnect the following fuel lines from the tank e Fuel out at fuel tank lock off e Fuel in from fill valve e Liquid level gauge Position a suitable tank support lifting device under the tank Secure the tank to the device Remove the tank to bracket nuts and bolts Remove the tank from the vehicle If the tank is being replaced drain the tank Refer to Propane Fuel Tank Draining Website 9 2 03 Installation Procedure Using a suitable tank support lifting device raise and position the tank under the vehicle Install the tank bracket nuts and bolts
82. OPANE FUEL SYSTEM NORMAL MAINTENANCE REPLACEMENT PARTS F4 20804 001 AC Delco 41 932 0 060 LPG Fuel Filter Spark Plugs Spark Plug Gap 2002 LPG G Van Service Manual Supplement Page 8 QUANTUM PROPANE FUEL SYSTEM Power Ground MIL Wait to Drive Lamp and AF Enable peay JapunAo W I Jo 1988 COLD osr 900S 18 410 L005 essa EA FF aon LZ EE o34 punog puna punog pe WOd einpow ainpo F indino I09UOD wen uam jouog euiBuay GV eng AA yydwe7 eAuq ee J9MOd J9MOd UIBIEMOd IN meu yy feng SAHEUEY eAgeujeyv THN c_OJL HEM uoniub Kieyeg 1 seo coe ae eee dL p c rol I daw zo l 9v 77777 eg N18 lg co zc Le 419 1002 z009 LHM 6v WE 616 Ma xd peaH JapunAo een Paci Wal uoniub 019 000 A 3 ol VL6 Idd 000 6lb LHWNS8 020OL ANd OvEL sjueuoduo 6ELS GOEL due IW duer ozor Nd e ug Joyeotpuj t009 o uojounyye A A 0019 Y zo Jeued jueunusu ozoL 20 Joe E is Aejoy esny pooujepun DIAGNOSTIC INFORMATION AND PROCEDURES Engine Controls Schematics 2002 LPG G Van Service Manual Supplement Page 9 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Fuel and Idle Control Solenoids and Underhood Low Pressure Lock off LPL Solenoid euBis SOs picuejos joUOD feng 479 1009 e 116 NYS LI c00S V S94 30014 piouetos J09002 jen soos 026 038 jeubig plouajog 147 40 507 amssalJ MOT HN 106 Ma 1
83. PG G Van Service Manual Supplement Page 137 QUANTUM PROPANE FUEL SYSTEM Value s ves mo Use a scan tool to establish communication with the AF ECM Start and idle the engine until normal operating temperature is reached 0 10 to 1 0 Use the scan tool to monitor the HO2S B2 S1 volts voltage Is the voltage fixed within the specified range Go to Step 6 Go to Step 17 Turn the ignition OFF Disconnect the HO2S B2 S1 electrical connector Jumper the HO2S low circuit to a known good ground Jumper the HO2S high signal circuit to a know 20 mV good ground Turn the ignition ON leaving the engine OFF Use the scan tool to monitor the HO2S B2 S1 voltage Is the voltage less than the specified value Go to Step 9 Go to Step 7 Turn the ignition OFF Remove the jumpers from the HO2S terminals Disconnect the PCM connector containing the HO2S high and low circuits Use a DVOM to measure continuity of the HO2S 5 ohms high signal circuit and HO2S low signal circuit between the PCM connector and the HO2S connector terminal engine harness side Are both resistances less than the specified value Go to Step 8 Go to Step 11 1 Inspect for proper PCM connector terminal Go to Step 22 Goto Step 21 contact 2 Repair the terminals as necessary Was a terminal repair made 1 Remove the jumpers from the HO2S terminals 2 Connect a test lamp between the HO2S heater ignition feed and heater ground circuit t
84. RN DK BLU 417 ORN BLK 469 020 TRNEK 432 021 BLK 2761 BLK 2760 BLK 2752 D 469 S019 DK BLU ORN BLK 469 A i E DK BLU 417 C005 LT GRN 432 C1 c2 C1 C1 LT GRN 432 80 4 BLU 57 RED 60 BLU 24 C2 RED 54 BLU 32 C2 RED 44 de C002 BLU s Sensor n Sensor XL Senes Sensor TP Sensor Sensor MAP Sensor i 1 2 ES Sensor W Sensor a MAP Sensor 1 l Ground Ground Ground Signal Ground Signal 1 Signal Ground Signal 1 D MN 1 RD UELUT DE EN ee aes SPINE rd Powertrain Control Module PCM Alternative Fuel Engine Control Module AF ECM Conditions for Running the DTC The engine has been operating for greater than 1 minutes when the engine start up temperature is greater than 0 C or 32 F OR The engine has been operating for greater than 10 minutes when the engine start up temperature is 0 C or 32 F or less e Vehicle speed is less than 1 mph for at least 10 seconds continuously e Mass air flow is less than 250 grams per second for at least 10 seconds continuously Conditions for Setting the DTC The AF ECM monitors and IAT sensor voltage greater than 4 9 volts for at least 5 seconds continuously 2002 LPG G Van Service Manual Supplement Page 73 QUANTUM PROPANE FUEL SYSTEM Action Taken When the DTC Sets The first failure of this DTC will not illuminate the MIL and will store as Last Test Failed but not as history The AF ECM will illuminate the MIL and store
85. STEM DTC P0132 DTC 45 HO2S Circuit High Voltage Bank 1 Sensor 1 Value s Yes No Did you perform the Alternative Fuels AF Powert rain On Board Diagnostic OBD System Check Go to AF Powertrain BD Go to Step 2 S pm Run the engine until normal operating temperature is reached Using a scan tool establish communication with the AF ECM 1 0 volts Using a scan tool monitor the AF ECM HO2S B1 S1 voltage Is the HO2S voltage fixed greater than the value specified n Go to Step 5 Go to Step 3 Go to Step 15 Go to Step 4 Are there any DTCs stored that have not been diagnosed EIC oo AF DTC List Intermittents Run the engine until normal operating temperature is reached Using the scan tool establish communication with the PCM 1 0 volts Using a scan tool monitor the HO2S B1 S1 voltage Is the HO2S voltage fixed greater than the value ified Species Go to Step 6 Goto Step 12 2002 LPG G Van Service Manual Supplement Page 109 The fault is not present Refer to Diagnostic Aids The condition that set this DTC is not present This DTC may have been set by one of the following conditions A signal wire intermittently shorted to voltage A silicon contaminated HO2S An intermittent rich condition such as the following Incorrect fuel pressure Low coolant level cooling system not bled at LPR Leaking low pressure regulator LPR Rich condition at fuel mixer Rich condition at FCS Rich cond
86. SYSTEM aer 4 Adin 4 CSC Go to Step 17 Repair the open ECT sensor signal circuit between ER Go to Step 17 Go to Step 16 the 10 way AF connector C005 and the AF ECM Is the circuit repair complete 1 Inspect for proper terminal contact at the AF ECM connector 2 Repair the terminal contact as necessary Was a terminal repair made Replace the AF ECM Refer to AF ECM Replacement Go to Step 17 System OK Go to Step 2 Is the replacement complete Using the scan tool clear the DTC information from BOTH control modules Operate the vehicle under the Conditions for Running the DTC Using the scan tool parameter DTC STATUS ensure that this DTC runs Did this DTC RUN and PASS Important The following PCM replacement procedures must be completed before attempting to operate the vehicle 1 Replace the PCM Refer to PCM Replacement in Engine Controls in the GM G VAN service manual Program flash the replacement PCM with the correct LPG software and calibration Is the replacement complete Go to Step 17 2002 LPG G Van Service Manual Supplement Page 84 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM DTC P0121 DTC 26 Throttle Position TP Sensor Performance Circuit Description The throttle position TP sensor is a potentiometer The PCM supplies about 5 volts on the TP sensor reference voltage circuit The PCM also supplies a ground circuit to the TP sensor When the t
87. Sensor 1 PNK HO2S B251 Signal Ignition Power B2 S1 Ground HO2S Bank 1 Sensor 1 G103 Circuit Description The heated oxygen sensor is used to determine the oxygen content of the engine s exhaust The oxygen content indicates when the engine is operating lean or rich When the engine is operating lean the exhaust will have more oxygen content Once at operating temperature the HO2S will produce a voltage in relation to the oxygen content of the exhaust The HO2S requires an operating temperature of 600 F 360 C to produce voltage The HO2S will produce more voltage when the exhaust is rich and less voltage when the exhaust is lean The HO2S operating range is around 0 10 volts 100 mV to 1 volt 1000 mV The PCM supplies a bias or reference voltage to the HO2S This bias voltage is around 450 mV The AF ECM monitors the bias voltage as well as the voltage produced by the HO2S During normal closed loop fuel control the AF ECM will add fuel richen the mixture when the HO2S indicates a lean exhaust content When the HO2S indicates a rich exhaust content the AF ECM will add fuel lean the mixture This oscillation above Website 9 2 03 Powertrain 1 Control Module PCM 1 C1 BLU 1667 4 i Alternative Fuel TE 1 Engine Control Signal Module AF ECM be 4 3 C001 CLR C004 TAN C004 Heated Oxygen Sensor HO2S B
88. Step 8 Go to Step 9 The HO2S may be detecting a rich exhaust condition Inspect for one of the following conditions HO2S connector water intrusion Silicone contaminated HO2S Fuel contaminated engine oil Incorrect fuel pressure Low coolant level cooling system not bled at LPR Leaking low pressure regulator LPR Rich condition at fuel mixer Rich condition at FCS Rich condition at ICS An inaccurate MAF sensor Repair any of the above or similar engine conditions as necessary Was a condition found and repair Go to Step 15 Go to Step 13 2002 LPG G Van Service Manual Supplement Page 132 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM on Vales ves Ne Turn the ignition OFF Remove the jumper from the HO2S low circuit terminal Disconnect the PCM connector that contains the HO2S B2 S1 high signal circuit 20 mV Turn the ignition ON leaving the engine OFF Using a DVOM measure and record the voltage between the HO2S high signal circuit and ground Is the voltage measured greater than the value specified Go to Step 10 Go to Step 14 voltage Repair the HO2S signal circuit high circuit shorted to Go to Step 15 Go to Step 15 Go to Step 12 Is the action complete The HO2S may be detecting a rich exhaust condition Perform the AF Fuel System Diagnosis and return to this step Was a rich AF fuel system condition found and repaired Replace the HO2S Refer to HO2S Replace
89. System Checks e Check the exhaust system for a possible restriction Inspect the exhaust system for damaged or collapsed pipes Inspect the muffler for signs of heat distress or for possible internal failure e Check for possible plugged catalytic converter Refer to Restricted Exhaust System Diagnosis or Exhaust System in the GM G Van Service Manual Additional Checks e Verify the correct LPG specific PCM software is installed 2002 LPG G Van Service Manual Supplement Page 172 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Cuts Out Misses DEFINITION A surging or jerking that follows engine speed usually more pronounced as the engine load increases which is not normally felt above 1500 RPM or 48 km h 30 mph The exhaust has a steady spitting sound at idle low speed or hard acceleration for the fuel starvation that can cause the engine to cut out Preliminary Checks e Refer to Important Preliminary Checks Ignition System Checks e Start the engine e Wet down the secondary ignition system with water from a spray bottle and look listen for arcing or misfiring as you apply water Check for proper ignition output voltage with spark tester J 26792 Check for a cylinder misfire Verify that the spark plugs are correct Remove the spark plugs in these cylinders and check for the following conditions e Insulation cracks e Wear Improper gap Burned electrodes Heavy deposits Visually Physically inspect the se
90. T Connect the line to the liquid level gauge Connect the following electrical connectors e Fuel tank lock off e Fuel sending unit Fill the propane fuel tank Website 9 2 03 Leak check the propane fuel system at the liquid level gauge Install the fuel tank cover and mounting bolts e Tighten the bolts to 16 Nem 12 lb ft Connect the negative battery cable LIQUID LEVEL GAUGE FILL VALVE REPLACEMENT Removal Procedure 1 2 Disconnect the negative battery cable Shut the liquid level gauge at the fuel tank off by turning clockwise Relieve the fuel pressure in the liquid level gauge line Refer to Propane Fuel System Pressure Relief Remove the liquid level gauge from the fill valve bracket Installation Procedure Important 4 5 Do not use Teflon tape on any fuel fitting Use liquid pipe thread sealant Apply liquid pipe thread sealant to the liquid level gauge threads Install the liquid level gauge to the fill valve bracket e Tighten the liquid level gauge to 2 3 TFFT Open liquid level gauge at fuel tank by turning valve counter clockwise Leak check the propane fuel system at the liquid level gauge Connect the negative battery cable FUEL LINE REPLACEMENT TANK TO FRAME UNION Removal Procedure 1 6 Relieve the propane fuel system pressure Refer to Propane Fuel System Pressure Relief Disconnect the negative battery cable Remove any clips clamps or brackets from t
91. TC e Engine speed is greater than 400 RPM e The engine has been operating for at least 1 minute e The oxygen sensor has been at operating temperature for at least 30 seconds The engine coolant temperature must be greater than 50 C AND the mass air flow above 4 4 gms sec for at least 30 seconds for the AF ECM to determine the HO2S is at operating temperature 2002 LPG G Van Service Manual Supplement Page 113 QUANTUM PROPANE FUEL SYSTEM Conditions for Setting the DTC The AF ECM monitors an HO2S signal voltage stuck between 0 300 V and 0 600 V in active for 8 seconds continuously OR The AF ECM monitors an HO2S signal voltage between 0 00 V and 1 0 V that has not performed a rich lean switch for 8 seconds continuously Action Taken When the DTC Sets The AF ECM will control fuel trim based upon the Bank 2 Sensor 1 signal If a Bank 2 Sensor 1 DTC sets the AF ECM will operate in open loop fuel control A first failure of this DTC will NOT illuminate the MIL and will store as Last Test Failed but not as History The AF ECM will illuminate the MIL and store the DTC as History TWO consecutive drive trips that the diagnostic runs and fails The AF ECM will record operating conditions at the time the DTC sets This information will be stored as Freeze Frame data Conditions for Clearing the MIL DTC The Last Test Failed status will clear when the DTC runs and passes The AF ECM will turn OFF the MIL aft
92. TUM PROPANE FUEL SYSTEM Backfire DEFINITION The fuel ignites in the intake manifold or in the exhaust system making a loud popping noise Preliminary Check e Refer to Important Preliminary Checks Ignition System Checks Engine Mechanical Check Website 9 2 03 Important LPG being a gaseous fuel requires higher secondary ignition system voltages for the equivalent gasoline operating conditions The ignition system must be maintained in peak condition to prevent backfire e Check for the proper ignition coil output voltage using the spark tester J26792 or the equivalent Check the spark plug wires by connecting an ohmmeter to the ends of each wire in question If the meter reads over 5 000 ohms replace the wires Note The vehicle may be equipped with low resistance plug wires refer to G Van service manual for proper plug wire resistance Check the connection at each ignition coil Check for deteriorated spark plug wire insulation Verify that the correct spark plugs are correct Remove the plugs and inspect them for the following conditions Wet plugs Cracks Wear Improper gap Burned electrodes Heavy deposits Check the ignition system Refer to Ignition System Diagnosis in the GM G Van Service Manual Important The AF system works on a fumigation principle of fuel introduction and is more sensitive to intake manifold leakage than a gasoline fuel supply system e Check the engine for the following
93. UTION The propane fuel system operates at pressures up to 312 psi To minimize the risk of fire and personal injury relieve the propane fuel system pressure where applicable before servicing the propane fuel system components CAUTION After relieving propane fuel system pressure a small amount residual pressure will be present Ensure the work area is well ventilated before disconnecting any fuel line Using GM Tech 2 1 2 3 4 Connect a GM Tech 2 Start the vehicle From the PCM Device Controls menu for the L31 V8 command the gasoline fuel pump relay OFF CLOSED Run the engine until it stalls Using Manual Shut off Valve 1 2 Close the manual shut off thumb wheel on the fuel tank lock off solenoid Start and run the engine until it stalls PROPANE FUEL SYSTEM LEAK TEST CAUTION Never use an open flame of any type to check for propane fuel system leaks Always inspect the propane fuel system for leaks after performing service Check for leaks at the fittings of the serviced or replaced component Use a commercially available liquid leak detector or an electronic leak detector When using both methods use the electronic leak detector first to avoid contamination by the liquid leak detector Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM PROPANE FILL VALVE REPLACEMENT Removal Procedure 1 ok k Disconnect the negative battery cable Slowly open the fuel line
94. XD Assembly Use Only AT ora 15 DKGRN 817 VSS Signal WHT 16 NotUsed MAF Sensor Signal Signal 19 231 NotUsed 2326 NotUsed 29 GRY 2704 Voltage Reference High 39 Nxused 32 NotUsea 2002 LPG G Van Service Manual Supplement Page 17 QUANTUM PROPANE FUEL SYSTEM Inline Harness Connector C004 GRY lalala Connector Part 12065426 AF Harness Side Connector Part 12052189 OEM Harness Side Information 10 Way Metri Pack Sealed 150 Information 10 Way Metri Pack Sealed 150 Series GRY Series GRY Wire Circuit Wire Circuit Color No Function Color No Function MAF Sensor Signa MAF Sensor Signa DKGRN 817 VSS Signal DKGRN 817 VSS Signal WHT WHT 23 D war 12 EngmeSpeediRPMySigna D WHT 121 Engine Speed RPM Signal HO2S 81 Signal HO2S Low HO25 B2 Signal Psp mot 3 ote Batiery Power K ORN 1540 Battery Power Inline Harness Connector C005 BLK Jalal Connector Part 12065425 AF Harness Side Connector Part 12045808 OEM Harness Side Information e 10 Way Metri Pack Sealed 150 Information 10 Way Metri Pack Sealed 150 Series BLK Series BLK Wire Circuit Wire Circuit nl coor os o nee e e LL pue B TN 472 Mses B TAN 42 Wi n D GRv 2704 Voltage Reference High D GRY 2704 Voltage Reference Hi
95. aired Go to Step 18 Goto Step 17 Was a problem found Replace the AF ECM Refer to AF ECM terminals and the HO2S connector terminals Replacement Important Inspect these circuits for shorts to other circuits or to ground Ensure the oxygen sensor gasoline control module and the AF ECM connectors are disconnected before testing circuits 3 Repair the wiring as necessary The following PCM replacement procedures must be completed before attempting to operate the vehicle 1 Replace the PCM Refer to PCM Replacement in Engine Controls in the GM G Van service manual Program flash the replacement PCM with the correct LPG software and calibration Is the replacement complete E Important The HO2S must be cool before proceeding with this diagnosis The ignition must remain OFF for at least one half hour before proceeding with diagnosis 1 Connect a scan tool 2 Set up the scan tool with the proper vehicle 150 mV identification information prior to turning the ignition ON Turn the ignition ON leaving the engine OFF and as quickly as possible observe and record the HO2S voltage for the sensor that applies to this DTC Observe the HO2S voltage for 2 minutes Does the voltage increase or decrease from the initial voltage by at least the specified value System OK Go to Step 2 2002 LPG G Van Service Manual Supplement Page 145 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM DTC P0
96. al Supplement Page 65 The AF ECM will turn OFF the MIL after THREE consecutive drive trips that the DTC runs and passes The History status will clear after FORTY consecutive WARM UP cycles with NO failures of ANY DTC All information can be cleared using a scan tool Interruption of Control Module AF ECM PCM power and ground MAY clear DTC information QUANTUM PROPANE FUEL SYSTEM DTCs were stored proceed to the applicable DTC table in the order stated in the OBD System Check Test Description The numbers below refer to the step numbers on the diagnostic table 2 This step determines if the failure condition affects the PCM 3 This step determines if the failure condition is present 5 This step determines if the MAP sensor is the shorted condition 6 This step determines if the open sensor ground condition is present 7 This step determines if the 5 volt reference circuit is shorted to a voltage 5 2 volts is the maximum output that the PCM should apply to the 5 volt reference circuit Clearing DTC information with this method is inconsistent and should not be performed Diagnostic Aids Fault Not Present Fault Not Present indicates the condition that caused the DTC to set is intermittent and not currently present Refer to Intermittents in Symptom diagnosis for additional information If any additional Important The MAP sensor data parameter is only active while the engine is running 1
97. alent gasoline operating conditions Check for the proper ignition voltage output with J 26792 or the equivalent Verify that the spark plugs are correct Check the spark plugs for the following conditions Wet plugs Cracks Wear Improper gap Burned electrodes Heavy deposits Check for bare or shorted ignition wires Check for loose ignition coil connections at each coil Important The AF system works on a fumigation principle of fuel introduction and is more sensitive to intake manifold leakage than the gasoline fuel supply system e Check for the following Vacuum leaks Improper valve timing Low compression Bent pushrods Worn rocker arms Broken or weak valve springs Worn camshaft lobes Check the exhaust system for a possible restriction Inspect the exhaust system for damaged or collapsed pipes Inspect the muffler for signs of heat distress or for possible internal failure Check for possible plugged catalytic converter Refer to Restricted Exhaust System Diagnosis or Exhaust System in the GM G Van Service Manual 2002 LPG G Van Service Manual Supplement Page 170 QUANTUM PROPANE FUEL SYSTEM Hard Start ee D er DEFINITION The engine cranks OK but does not start for a long time The engine does eventually run or may start but immediately dies Preliminary Checks e Refer to Important Preliminary Checks e Make sure the vehicle s operator is using the correct starting procedure Sensor Ch
98. als Note If the fuse of the jumper opens repair the short to 0 019 volts voltage in the IAT sensor signal circuit If a short to voltage condition is observed inspect the sensor for and open condition for an open after the wiring repair is made Does the IAT sensor data parameter indicate IAT voltage less than the specified value Connect the fused jumper between the IAT sensor signal circuit and a good known ground 0 019 volts Does the IAT sensor data parameter indicate IAT voltage less than the specified value Turn the ignition OFF Disconnect the PCM connector that contains the IAT sensor signal circuit With the IAT sensor connector disconnected test the IAT signal circuit for continuity Is IAT signal circuit continuity indicated Replace the IAT sensor Refer to AT Sensor Replacement in Engine Controls in the GM G VAN service manual Is the replacement complete Go to Step 17 Go to Step 17 ER Repair the open sensor ground circuit between the MAF IAT sensor connector and the PCM Is the circuit repair complete Repair the open in the sensor signal circuit between the MAF IAT sensor connector and the PCM Is the circuit repair complete Go to Step 17 Go to Step 17 Goto Step 15 Go to Step 13 Go to Step 14 2002 LPG G Van Service Manual Supplement Page 75 1 Inspect for proper terminal contact at the PCM connector 2 Repair the terminal as necessary Was a terminal repair made Turn the ig
99. amaged harness A poor ECM to the engine block ground Faulty Idle Control Solenoid ICS or ICS circuit Faulty Fuel Control Solenoid FCS or FCS circuit Faulty fuel mixer Faulty Low Pressure Regulator LPR Exhaust leaks If there is an exhaust leak the engine may pull the outside air into the exhaust and past the sensor Vacuum or crankcase leaks can cause a lean condition or possibly a high idle If the above check out okay the problem may be a faulty heated sensor A faulty HO2S Bank 1 Sensor 1 heater or heater circuit With the ignition switch on but the engine off the HO2S Bank 1 Sensor 1 voltage displayed on a scan tool should gradually drop to below 0 150 volt indicating that the heater works properly If not disconnect the HO2S Bank 1 Sensor 1 and connect a test lamp between the terminals C and D If the test lamp does not light repair the open in the HO2S Bank 1 Sensor 1 ground circuit or the HO2S Bank 1 Sensor 1 ignition feed circuit If the test lamp lights replace the HO2S Bank 1 Sensor 1 The intermittent test With a scan tool monitor the HO2S Bank 1 sensor 1 signal voltage while moving the related connectors and the wiring harness with a warm engine running at part throttle in closed loop If the failure is induced the HO2S Bank 1 Sensor 1 signal voltage reading changes from its normal fluctuating voltage above 600 mV and below 300 mV to a fixed value around 450 mV Th
100. ank 2 Sensor 1 and below the bias voltage sometimes referred to as activity or switching can be monitored with the HO2S signal voltage The oxygen sensor contains a heater The heater is used to quickly warm the sensor to operating temperature The heater will also maintain operating sensor temperature during extended idle conditions A functions oxygen sensor heater will allow the sensor to produce voltage in less time A sensor at operating temperature will cause the HO2S signal voltage to go above or below depending upon exhaust oxygen content the bias voltage This DTC is used to indicate an HO2S signal voltage that did not leave the cold sensor bias voltage range in an acceptable amount of time This DTC is a type B DTC Conditions for Running the DTC e AF ECM DTCs P0117 15 P0118 14 P0125 16 P0151 64 P0152 65 P0154 63 are not set 2002 LPG G Van Service Manual Supplement Page 141 QUANTUM PROPANE FUEL SYSTEM e The start up engine coolant temperature is less than 91 F 33 C e The engine has been operating for at least five seconds e The average mass air flow is less than 35 grams per second e All other AF ECM DTCs for this HO2S sensor have ran and passed e This DTC has not tested this ignition cycle e The AF ECM determines the HO2S was cold at ignition key ON The average HO2S signal voltage must be within the bias voltage range of 0 30 volts 300 mV to 0 60 volts 60
101. ant temperature with the ambient air temperature on a cold engine If the coolant temperature reading is more than 5 greater than or less than the ambient air temperature on a cold engine check for a high resistance in the coolant sensor circuit or the sensor itself Refer to DTC P1115 ECT Sensor CKT Intermittent High Voltage Diagnostic Aids or DTC P0118 ECT Sensor Circuit High Voltage Diagnostic Aids in the GM G Van Service Manual Check the Manifold Absolute Pressure MAP sensor response and accuracy Fuel System Checks Check for rich or lean symptom that causes the condition Drive the vehicle at the speed of the complaint Monitoring the oxygen sensors will help identify the problem Check the coolant level If coolant is added bleed the cooling system using the Schrader valve on the LPR Check for a sticking or dirty mixer air valve Verify proper operation of the idle control solenoid Verify proper operation of the fuel control solenoid Perform a cylinder compression test Refer to Engine Mechanical in the GM G Van Service Manual Check for leaking fuel injectors While the injectors are not used they provide a possible vacuum leak point Verify that the injector fuel rail plugs are in place Check the LPR fuel pressure Refer to the AF Fuel System Diagnosis Check mixer module assembly for proper installation and connection 2002 LPG G Van Service Manual Supplement Page 181 Website 9 2 03 QUANTUM PROPANE FUEL
102. at the diagnostic runs and fails e The AF ECM will record operating conditions at the time the DTC sets This information will be stored as Freeze Frame data Conditions for Clearing the MIL DTC e The Last Test Failed status will clear when the DTC runs and passes e The AF ECM will turn OFF the MIL after THREE consecutive drive trips that the DTC runs and passes e The History status will clear after FORTY consecutive WARM UP cycles with NO failures of ANY DTC e All information can be cleared using a scan tool e Interruption of Control Module AF ECM PCM power and ground MAY clear DTC information Clearing DTC information with this method is inconsistent and should not be performed Diagnostic Aids Fault Not Present Fault Not Present indicates the condition that caused the DTC to set is intermittent and not currently present Refer to Intermittents in Symptom diagnosis for additional information If any additional DTCs were stored proceed to the applicable DTC table in the order stated in the OBD System Check Always diagnose ANY PCM codes that are present before beginning this diagnostic procedure Check the following items e Fuel pressure The ECM can compensate for small increases in fuel pressure However large increases in fuel pressure may set a DTC e Faulty Fuel Control Solenoid FCS e Vacuum leaks in the fuel control valve hoses e False rich indication due to silicon contamination of the HO2S Th
103. ate MAF sensor An intake air duct leak between the MAF sensor and the throttle Exhaust system leaks between then engine and the oxygen sensors Repair any of the above conditions as necessary Was a condition found and repaired Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Sep Adon Vawg Yes No Reconnect all disconnected or removed components Using the scan tool clear all DTC information form both the PCM and the AF ECM Using the scan tool communicate with the AF ECM and reset the fuel trim values to zero Turn the ignition OFF and wait 30 seconds Start the engine View the captured freeze frame data that was stored in Step 2 Observe the data parameters that give an indication of how the vehicle was being operated when this DTC set Operate the vehicle within the conditions for running the DTC and the parameters observed when the DTC set Observe the short term fuel trim values Do the fuel trim values indicate a lean mixture condition is present or does a fuel trim DTC set Go to Step 7 Go to Step 6 The fault is not present Refer to Diagnostic Aids Go to Go to AF DTC List Intermittents Go to Step 12 Go to Step 12 Go to Step 9 2002 LPG G Van Service Manual Supplement Page 148 Are there any DTCs stored that have not been diagnosed Perform the AF Fuel System diagnosis and return to this step Refer to AF Fuel System diagnosis Was a LPG fuel system
104. ator if the vehicle has recently been run low or out of fuel e A poor connection or a damaged harness e Backed out terminals e Improperly formed or damaged terminals e Poor terminal to wire connection e Damaged harness e A poor ECM to the engine block ground e Faulty Idle Control Solenoid ICS or ICS circuit e Faulty Fuel Control Solenoid FCS or FCS circuit Faulty fuel mixer e Faulty Low Pressure Regulator LPR e Exhaust leaks If there is an exhaust leak the engine may pull the outside air into the exhaust and past the sensor e Vacuum or crankcase leaks can cause a lean condition or possibly a high idle e fthe above check out okay the problem may be a faulty heated sensor e A faulty HO2S Bank 2 Sensor 1 heater or heater circuit With the ignition switch on but the engine off the HO2S Bank 2 Sensor 1 voltage displayed on a scan tool should gradually drop to below 0 150 volt indicating that the heater works properly If not disconnect the HO2S Bank 2 Sensor 1 and connect a test lamp between the terminals C and D f the test lamp does not light repair the open in the HO2S Bank 2 Sensor 1 ground circuit or the HO2S Bank 2 Sensor 1 ignition feed circuit If the test lamp lights replace the HO2S Bank 2 Sensor 1 e The intermittent test With a scan tool monitor the HO2S Bank 2 sensor 1 signal voltage while moving the related connectors and the wiring harness with a warm engin
105. battery cable 11 Start the vehicle and leak check the propane fuel System at each serviced fitting 12 Install the engine cover and connect the retaining straps 13 Connect the electrical connectors for the lighter accessory plug and storage compartment lamp 14 Install the center consol 15 Install the center consol mounting hardware 16 Install the IP lower trim panel to the IP 17 Using the Schrader valve on the LPR bleed the cooling system 18 Start the vehicle and leak check the propane fuel System at each serviced fitting NOD FUEL CONTROL SOLENOID FCS REPLACEMENT Removal Procedure Disconnect the negative battery cable Remove the IP lower trim panel from the IP Remove the center consol mounting hardware Disconnect the electrical connectors for the lighter accessory plug and storage compartment lamp Remove the center consol 6 Release the engine cover retaining straps and remove the cover 7 Disconnect the FCS vacuum line from the solenoid 8 Disconnect the FCS electrical connector 9 Remove the two 2 FCS mounting bolts and the FCS Bom e Installation Procedure 1 Install the FCS and two 2 mounting bolts e Tighten the bolts to 12 Nem 9 lb ft Connect the FCS electrical connector Connect the FCS vacuum line to the solenoid Install the engine cover and connect the retaining straps 5 Connect the electrical connectors for the lighter accessory plug and storage
106. before attempting to operate the vehicle 3 Replace the PCM Refer to PCM Replacement in Engine Controls in the GM G Van service manual Program flash the replacement PCM with the correct LPG software and calibration Is the replacement complete Go to Step 18 Important The HO2S must be cool before proceeding with this diagnosis The ignition must remain OFF for at least one half hour before proceeding with diagnosis 1 Connect a scan tool 2 Set up the scan tool with the proper vehicle identification information prior to turning the ignition ON Turn the ignition ON leaving the engine OFF and as quickly as possible observe and record the HO2S voltage for the sensor that applies to this DTC Observe the HO2S voltage for 2 minutes Does the voltage increase or decrease from the initial voltage by at least the specified value System OK Go to Step 2 2002 LPG G Van Service Manual Supplement Page 123 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM DTC P0151 DTC 64 HO2S Circuit Low Voltage Bank 2 Sensor 1 Hot in Run And Start HO2S Bank 1 4 amp Sensor 1 PNK HO2S B2S1 Signal Ignition Power Ground HO2S Bank fi 4 4 Sensor 1 G103 Circuit Description The heated oxygen sensor is used to determine the oxygen content of the engine s exhaust The oxygen content indicates when the engine is operating lean or rich When the engine is operating lean
107. both the PCM and the AF ECM for stored DTCs If any DTCs are set record and store the DTC Freeze Frame and Failure Records information Were any DTCs stored Crank the engine for 10 seconds Go to No Start Go to Step 7 In Symptoms Go to the applicable DTC Go to Step 10 table Go to Step 12 Goto Step 11 2002 LPG G Van Service Manual Supplement Page 26 Does the engine start 1 Operate the vehicle and observe record the engine data parameters 2 Compare the engine data on the scan tool with the Engine Scan Tool Data List Are values normal or within typical range Check the Class 2 serial data circuit for an open or poor connection between the AF ECM and the serial data circuit splice Check battery power ignition power and ground to the AF ECM Refer to Engine Controls Schematics Repair circuits as necessary Command the MIL OFF using the scan tool Engine Output PCM for the MIL Go to Malfunction Does the MIL turn OFF Goto Step 6 Cee Was a circuit or terminal connection repair made Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM 1 Compare the stored PCM DTCs to the stored AF ECM DTCs 2 Diagnose DTCs in the following order e Ifa DTC is stored ONLY in the PCM refer to the applicable DTC table in the GM G Van service manual If a DTC is stored in BOTH control modules or only in the AF ECM refer to the applicable DTC table in this manual If DIFFERENT multiple DTCs are stored diag
108. cat Powertrain Power Power Control Control Fuel AF t 1 H Fuel AF ntrol d Output input Enable Engine Control Enable Control 1 Module Module PCM j Ground Ground Ground Ground AF ECM Ion S006 Ground Back of Right Cylinder Head Diagnostic Aids 3 This step verifies battery power ignition power and ground to the AF ECM Intermittent Always diagnose ANY PCM codes that are present connections may cause the AF ECM to store before beginning this diagnostic procedure multiple false codes If the AF ECM has stored an A poor connection a rubbed through wire insulation excessive number of DTCs for no apparent or a wire broken inside the insulation may cause an reason check each of these circuits for an intermittent intermittent connection Check for the following conditions e A poor connection or damaged harness Inspect the ECM harness connector for the following conditions Backed out terminals Improper mating Broken locks Improperly formed or damaged terminals Poor terminal to wire connection and Damaged harness Test Description The numbers below refer to the step numbers on the diagnostic table 2002 LPG G Van Service Manual Supplement Page 162 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM DTC P0601 DTC 58 AF ECM Internal Failure Value s Yes m Was the Alternative Fuels AF Powertrain On Board Go to AF Diagnostic OBD System Check performed Pow
109. ce Reference PCM bol Signal Signal Reference AF ECM 74 C1 BLU 25 NN C2 RED 8 48 C1 BLU IRAN 180 29 C002 BLU YEL 410 GRY 2704 TAI 2 YEL 410 TAN 472 GRY 2701 A B D YEL 017 410 TAN YEL 410 S018 472 TAN 472 GRY 022 A 2704 GRY 2704 A EE Temperature Throtte Manlio Temperature IAT Position solu ECT Sensor TP ea Sensor Sensor Sensor B c A B A B LTGRN 432 LT GRN DK BLU 417 ORN BLK 469 020 432 ORN BLK 021 BLK 2761 BLK 2760 BLK 2752 D 469 S019 DK BLU ORN BLK 469 A i E Ge DE ie C005 LT GRN 432 ORN C1 c2 C1 C1 pk BLU 417 P rend 432 80 de BLU S e 90 BLU 24 C2 RED 54 BLU 32 C2 RED 27 y 728 dj 4 dr C002 BLU Sensor Sensor Sensor TP Sensor Sensor MAP Sensor TP Sensor Sensor MAP Sensor Ground Ground Ground Signal Ground Signal Signal Ground Signal Alternative Fuel Engine Control Module AF ECM Conditions for Running the DTC The engine is operating Conditions for Setting the DTC The AF ECM monitors a TP sensor signal voltage of less than 0 09 volts for at least 1 second continuously Action Taken When the DTC Sets e A first failure of this DTC will NOT illuminate the MIL and will store as Lest Test Failed but not as History e The AF ECM will illuminate the MIL and store the DTC as History after TWO consecutive drive trips that the diagnostic runs and fails e The AF ECM will record operating conditions at the time the
110. ck for the loss of the DTC Memory disconnect the MAF sensor Idle the engine until the Malfunction Indicator Lamp illuminates The PCM and should store a MAF DTC The MAF DTC should remain in the memory when turning off the ignition If the MAF IAT DTC does not store and remain the PCM is faulty The ECM memory may be checked in the same manner by selecting a DTC and intentionally setting the fault Additional Checks Check for an open diode across the A C compressor clutch and for other open diodes 2002 LPG G Van Service Manual Supplement Page 168 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM No Start DEFINITION The engine cranks OK but does not start Preliminary Checks e Control Module Checks e Sensor Checks Refer to Important Preliminary Checks If a scan tool is available Check for proper communication with both the PCM and the AF ECM Verify the correct LPG specific PCM software is installed Check the AF enable circuit from the AF ECM Check the 20A CNG ECM 1 and ECM B fuses in the underhood fuse relay center Refer to Engine Controls Schematics Check the 10A TRANS fuse in the IP fuse block Refer to Engine Controls Schematics Check the fuel pump relay in the underhood fuse relay center Refer to Engine Controls Schematics Check battery power ignition power and ground circuits to the AF ECM Refer to Engine Control Schematics Verify voltage and or continuity for each circuit Check
111. compartment lamp Install the center consol Install the center consol mounting hardware Install the IP lower trim panel to the IP Connect the negative battery cable Bom o OND 2002 LPG G Van Service Manual Supplement Page 191 QUANTUM PROPANE FUEL SYSTEM IDLE CONTROL SOLENOID ICS REPLACEMENT Removal Procedure ops Disconnect the negative battery cable Remove the IP lower trim panel from the IP Remove the center consol mounting hardware Disconnect the electrical connectors for the lighter accessory plug and storage compartment lamp Remove the center console Release the engine cover retaining straps and remove the cover Disconnect the ICS fuel supply line from the solenoid Disconnect the ICS electrical connector Remove the two 2 ICS mounting bolts and the ICS Installation Procedure 1 Bom o OND Install the ICS and the two mounting bolts e Tighten the bolts to 12 Nem 9 lb ft Connect the ICS electrical connector Connect the ICS fuel supply line to the solenoid Install the engine cover and connect the retaining straps Connect the electrical connectors for the lighter accessory plug and storage compartment lamp Install the center consol Install the center consol mounting hardware Install the IP lower trim panel to the IP Connect the negative battery cable FUEL MIXER OUTLET ELBOW COVER ASSEMBLY REPLACEMENT Removal Procedure 1 2 10 11 Disconnect
112. condary ignition for the following Ignition wires for arcing cross firing and proper routing Ignition coils for cracks or carbon tracking Engine Mechanical Checks Perform a cylinder compression check Check the engine for the following Improper valve timing Bent pushrods Worn rocker arms Worn camshaft lobes Broken or weak valve springs Check the intake and exhaust manifold passages for casting flash Fuel System Checks Check the fuel system plugged fuel filter low fuel pressure etc Refer to AF Fuel System Diagnosis e Check the condition of the wiring to the low pressure lock off solenoid Additional Check Check for Electromagnetic Interference EMI EMI on the reference circuit can cause a missing condition Monitoring the engine RPM with a scan tool can detect an EMI A sudden increase in the RPM with little change in the actual engine RPM indicates EMI is present If the problem exists check the routing of the secondary wires and the ground circuit 2002 LPG G Van Service Manual Supplement Page 173 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Hesitation Sag Stumble ms Am DEFINITION The vehicle has a momentary lack of response when depressing the accelerator The condition can occur at any vehicle speed The condition is usually most severe when trying to make the vehicle move as from a stop sign The condition may cause the engine to stall if i s severe enough Preliminary Checks Refer to Impo
113. connect the PCM connector that contains the HO2S B1 S1 high signal circuit Using a DVOM measure and record the resistance between the HO2S high signal circuit and ground Using a DVOM measure and record the resistance between the HO2S high signal circuit and the HO2S low circuit Is infinite resistance measured on both tests Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM ae aam Values No The HO2S may be detecting a lean exhaust Perform the AF Fuel System Diagnosis and return to this step Go to Step 16 Go to Step 13 Go to Step 16 Was a lean AF fuel system condition found and repaired Replace the AF ECM Refer to AF ECM Replacement Is the replacement complete Replace the HO2S Refer to HO2S Replacement in Engine Controls in the GM G VAN service manual Is the replacement complete Go to Step 16 Reconnect all disconnected or removed components connectors LPL test jumper fuses etc Using the scan tool clear the DTC information from BOTH control modules Using the scan tool communicate with both control modules to reset the fuel trim values to zero Operate the vehicle under the Conditions for Running the DTC Using the scan tool parameter DTC STATUS ensure that this DTC runs Important The following PCM replacement procedures must be completed before attempting to operate the vehicle 1 Replace the PCM Refer to PCM Replacement in Engine Controls in the GM G VAN service manual
114. containing the PCM ground circuits 500 ohms Using a DVOM measure the resistance between the HO2S low circuit terminal and one of the PCM grounds Is the resistance less than the specified value Go to Step 14 Go to Step 13 2002 LPG G Van Service Manual Supplement Page 116 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Sep tion vawe Ye mw Repair the circuit that measured high resistance Go to Step 17 Go to Step 22 o Was an exhaust system repair made Go to Step 22 Goto Step 15 1 Allow the engine to cool to ambient temperature 2 Using a DVOM re measure the resistance between the HO2S low circuit terminal and a 500 ohms PCM ground circuit terminal Is the resistance less than the specified value Go to Step 19 Goto Step 16 Remove the HO2S from the exhaust Clean the HO2S mounting threads Apply HO2S safe anti seize compound to the sensor threads Tighten the HO2S to the proper torque Refer to HO2S Replacement in the GM G Van service 500 ohms manual Using a DVOM measure the resistance between the HO2S low circuit terminal and a PCM ground circuit terminal Is the resistance less than the specified value Go to Step 22 Goto Step 20 2002 LPG G Van Service Manual Supplement Page 117 Did you complete the repair Repair the HO2S heater ignition or ground circuit Possible causes include the following An open circuit A high circuit resistance A faulty ground connection A blown heat
115. cuit Is the voltage within the specified range Go to Step 18 Go to Step 13 1 Test the 5 volt reference circuit for a short to voltage above 5 2 a short to ground or high circuit resistance below 4 8 volts 2 Repair wiring as necessary Was a wiring repair made Go to Step 19 Go to Step 17 Go to Step 19 Goto Step 18 Was a repair made P Go to Step 19 Go to Step 17 Replace the TP sensor Refer to TP Sensor Replacement in Engine Controls in the GM G Van service manual Is the replacement complete Go to Step 19 Important Go to Step 19 The following PCM replacement procedures must Go to Step 19 be completed before attempting to operate the 2002 LPG G Van Service Manual Supplement Page 88 Inspect the TP sensor signal circuit for an open or high resistance condition between the AF ECM connector terminal and the circuit splice Inspect the AF ECM connect and any in line connectors if applicable for proper terminal contact Repair wiring or terminals as necessary Was a repair necessary Test the TP sensor ground circuit for high resistance or poor terminal contact at the PCM connector Repair wiring or terminal contact as necessary vehicle 1 Replace the PCM Refer to PCM Replacement in Engine Controls in the GM G Van service manual 2 Program flash the replacement PCM with the correct LPG software and calibration Is the replacement complete Replace the AF ECM Refer to AF ECM Rep
116. d and corrected Repair the open or short as necessary Is the action complete 1 Check the OEM to the VSS circuit splice for an open short to ground or short to power 2 Repair the problem as necessary Go to DTC P0500 VSS Circuit in the GM G Van service manual Go to Step 11 M Y Go to Step 12 Go to Step 2 Go to the Applicable DTC Table System OK Was a problem found Using the scan tool clear the DTC information from BOTH control modules Operate the vehicle under the Conditions for Running the DTC Using the scan tool parameter DTC STATUS ensure that this DTC runs Did this DTC RUN and PASS Using the scan tool select the Capture Info and the Review Info Are there any DTCs stored that have not been diagnosed Replace the AF ECM Refer to AF ECM Replacement Is the action complete Go to Step 11 2002 LPG G Van Service Manual Supplement Page 161 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM DTC P0601 DTC 58 AF ECM Internal Failure Underhood Fuse Relay Center TRANS IP Fuse Fuse c2X C100 Malfunction Instrument Indicator Panel 1020 Lamp MIL C004 PNK To OEM Components F BRN WHT PNK K 1020 BRN WHT 419 To Ignition Relay BRN WHT 419 DK BLU 919 C002 BLU 53 C001 CLR 2 C2 RED 3 d Battery Ignition MIL MIL Alternative Alternative Fuel Alternative
117. d test lamp between the sensor ground circuit terminal and battery positive Is the test lamp illuminated Connect a DVOM between the 5 volt reference circuit terminal and ground Measure the voltage on the 5 volt reference circuit 5 2 volts Is the voltage less than the specified voltage Inspect all 5 volt reference circuits or a short to voltage Some 5 volt reference circuits are shared with the PCM The short may be located on either of the 5 volt reference circuits that the PCM provides Disconnect the AF ECM connector that contains the 5 volt reference circuit to determine if the ECM is the cause of the short to voltage Repair wiring as necessary Was a wiring repair made Inspect the sensor ground circuit for an open or high resistance condition between the sensor and the PCM connector terminal Inspect for proper terminal contact at both the PCM connector and the TP sensor connector Repair wiring or terminal contact as necessary Was a wiring or terminal repair necessary Test the TP signal circuit for a short to voltage Disconnect the AF ECM connector that contains the TP signal circuit to determine if the ECM is the cause of the short to voltage Repair wiring as necessary Was a wiring repair made Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Go to Step 14 Go to Step 13 Go to Step 18 Go to Step 18 Go to Step 17 Go to Step 18 Go to Step 18 Go to Step 18 System OK Go to Step 2
118. dicate IAT voltage less than the specified value Go to Step 3 Go to Step 4 1 Using the scan tool establish communication with the PCM 2 Observe the IAT sensor data parameter 0 019 volts Does the IAT sensor data parameter indicate IAT voltage less than the specified value Go to Step 5 Go to Step 8 The fault is not present Refer to Diagnostic Aids Go to Go to Are any DTCs stored that have not been diagnosed AF DTC List Intermittents Disconnect the IAT sensor Does the IAT sensor data parameter indicate IAT 0 019 volts voltage less that the specified value Go to Step 6 Go to Step 9 2002 LPG G Van Service Manual Supplement Page 70 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Value s ves mo Turn the ignition OFF Disconnect the PCM connector that contains the IAT sensor signal circuit Disconnect the ECM connector that contains the IAT sensor signal circuit With the IAT sensor connector disconnected test the IAT sensor signal circuit for continuity to engine ground and to the sensor ground circuit lf a shorted to ground IAT signal circuit is indicated repair the circuit as necessary Was an IAT sensor signal circuit repair made Go to Step 12 Go to Step 7 Connect the PCM connector that contains the IAT sensor signal circuit Leave the AF ECM connector disconnected Turn the ignition ON with the engine OFF 0 019 volts With the IAT sensor connector disconnected observe the PCM IAT sensor data
119. ding Unit Diagnosis Underhood Powertrain Underhood H 1 Fuse Relay Control Fuse Relay Fuel Level Fuel Pump Center Module PCM i Sensor Signal Relay Control Center L Di C2 RED DK GRN To OEM To OEM Components wr 465 Components i i Underhood i Fuse Relay To OEM H Components H i Center To C301 To Ignition Relay Fuel Tank Lock off Solenoid To OEM Components To Wait to Drive Light and Ignition Relay Powertrain Control Ground Rear of Right Cylinder Head Module PCM Circuit Description The LPG fuel sending unit FSU is mounted in the LPG tank assembly The sensor is powered by 12 volts and outputs a digital signal through the fuel level sensor signal circuit to the PCM The PCM drives the fuel gauge LPG Fuel Sending Unit Diagnosis Sep ion IL Valet Yes Ne Did you perform the Alternative Fuels AF Powertrain Go to AF On Board Diagnostic OBD System Check Powertrain OBD System Go to Step 2 Check Do all the other gauges on the instrument panel Go to appear to function correctly Instrument Panel Gauges and Console Gas in the G van Service Go to Step 3 Manual 2002 LPG G Van Service Manual Supplement Page 48 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM value s Yes Go to Does the fuel gauge read full Intermittents Go to Step 4 1 Disconnect the FSU connector 2 Connect DVOM across pins A and B 3 Turn the ignition key ON 9 6V 13
120. e WTD lamp circuit is controlled by the AF ECM and has two functions 1 The WTD lamp is used to indicate to the driver that the LPG fuel system is below a minimum operating temperature Before attempting to drive the vehicle MUST BE WARMED UP until the WTD lamp is OFF 2 The AF ECM OBD Powertrain System Check can be initialized to command two digit OBD blink codes to be displayed by the WTD lamp Using a scan tool the AF ECM output driver data will display WTD lamp control status while the engine is cranking or running Wait to Drive Lamp Circuit aer Adon Vau Yes Ne Did you perform the Alternative Fuels AF Powertrain Go to AF On Board Diagnostic OBD System Check Powertrain OBD System Go to Step 2 Check Turn ON the ignition with the engine OFF Is the WTD lamp continuously illuminated Go to Step 3 Go to Step 6 2002 LPG G Van Service Manual Supplement Page 34 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Weed Yes Ne Connect a scan tool 2 While communicating with the AF ECM command the WTD lamp OFF Is the WTD lamp illuminated Go to Step 5 Go to Step 4 Go to AF Powertrain OBD System Go to Check Intermittents Go to Go to Step 6 Intermittents Go to Step 13 Go to Step 7 Go to Step 12 Go to Step 11 Go to Intermittents Go to Step 9 Go to Step 13 Go to Step 10 Go to Step 13 Go to Step 10 Go to Step 13 MES 2002 LPG G Van Service Manual Supplement Page 35 T
121. e the DTC as History during ONE drive trip in which the diagnostic runs and fails e The AF ECM will record operating conditions at the time the DTC sets This information will be stored as Freeze Frame data Conditions for Clearing the MIL DTC e The Last Test Failed status will clear when the DTC runs and passes e The AF ECM will turn OFF the MIL after THREE consecutive drive trips that the DTC runs and passes e The History status will clear after FORTY consecutive WARM UP cycles with NO failures of ANY DTC e All information can be cleared using a scan tool e Interruption of Control Module AF ECM PCM power and ground MAY clear DTC information Clearing DTC information with this method is inconsistent and should not be performed Diagnostic Aids Fault Not Present Fault Not Present indicates the condition that caused the DTC to set is intermittent and not currently present Refer to ntermittents in Symptom diagnosis for additional information If any additional DTOCs were stored proceed to the applicable DTC table in the order stated in the OBD System Check Test Description The numbers below refer to the step numbers on the diagnostic table 2 This step determines if the failure condition affects the POM 3 This step determines if the failure condition is present 5 This step determines if the MAF sensor is generating the high frequency signal 6 This step determines if the AF ECM is generating the hig
122. e Fuel System Pressure Relief Disconnect the negative battery cable Remove the IP lower trim panel from the IP Remove the center consol mounting hardware Disconnect the electrical connectors for the lighter accessory plug and storage compartment lamp Remove the center consol Release the engine cover retaining straps and remove the cover Disconnect the fuel line from the LPL Remove the LPL to bracket mounting bolts Disconnect the LPL electrical connector Disconnect the ICS fuel line from the LPR Disconnect the FCS vacuum line from the LPR Remove the LPR to bracket mounting bolts Remove the fuel vapor hose clamp at the elbow Remove the LPR from the bracket with the coolant hoses attached Remove the LPL from the LPR Installation Procedure Important 1 Do not use Teflon tape on any fuel fitting Use a liquid pipe thread sealant when installing fittings Apply pipe thread sealant to the LPR inlet fitting Website 9 2 03 0 90 10 Install the LPL to the LPR Tighten the LPL finger tight plus 1 to 3 turns and place the LPL in the correct orientation Position the LPR on the mounting bracket while connecting the fuel vapor hose Install the fuel vapor hose clamp e Tighten the clamp to 2 Nem 18 Ib in Install the LPR to bracket mounting bolts e Tighten the bolts to 12 Nem 9 lb ft Connect the FCS vacuum line to the LPR Connect the ICS vacuum line to the LPR Connect the LPL electrical con
123. e GM Tech 2 or equivalent e Loose cracked or kinked vacuum hoses Pressure Gauges e Poor connection or a damaged harness to the e Water Column Gauge Manometer GM 7333 6 AF ECM FCS and ICS or equivalent e Poor AF ECM engine block ground e 0 10 PSI Gauge e Sticking mixer air valve e Intake air leak between mixer and throttle body Test Description e Faulty low pressure regulator LPR e Exhaust leaks The numbers below refer to step numbers on the e Fuel contamination diagnostic table E pog yS iT DIO AER 4 This test determines proper fuel control system Tools Required authority at idle e DVOM GM J 39200 Fluke 88 or equivalent 7 This test determines proper fuel control system Duty Cycle Monitoring Tool operation at 2500 RPM e DVOM GM J 39200 Fluke 88 or equivalent AF Fuel Control System Diagnosis Value s Yes J We Were you referred to this procedure by another diagnostic chart Go to Step 3 Go to Step 2 Perform the AF On Board Diagnostic OBD System Go to the applicable Are any DTCs present in the AF ECM DTC Table Go to Step 3 Go to AF Fuel System Go to Step 4 Diagnosis Connect a scan tool Start the engine and allow it to reach operating temperature With the engine idling observe the duty cycle 20 to 80 reading of the FCS on the scan tool Is the FCS duty cycle within the specified range Go to Step 6 Go to Step 5 5 20 ES Is the FCS duty cycle below the specified value MSN Goto St
124. e Last Test Failed status will clear when the DTC runs and passes The AF ECM will turn OFF the MIL after THREE consecutive drive trips that the DTC runs and passes The History status will clear after FORTY consecutive WARM UP cycles with NO failures of ANY DTC All information can be cleared using a scan tool Interruption of Control Module AF ECM PCM power and ground MAY clear DTC information Clearing DTC information with this method is inconsistent and should not be performed Diagnostic Aids Fault Not Present Fault Not Present indicates the condition that caused the DTC to set is intermittent and not currently present Refer to Intermittents in Symptom diagnosis for additional information If any additional DTCs were stored proceed to the applicable DTC table in the order stated in the OBD System Check Test Description The numbers below refer to the step numbers on the diagnostic table 2 This step determines if the failure condition affects the gasoline control module 3 This step determines if the failure condition is present 5 This step determines if the ECT sensor is the open condition 6 This step determines if the sensor ground circuit is the open condition 7 This step determines if the ECT signal circuit wiring is the open condition If the connector terminals pass inspection test the sensor signal circuit for a short to a 5 volt reference circuit Although an unlikely failure this condi
125. e Schrader valve on the LPR Check the fuel system pressures Refer to the AF Fuel System Diagnosis 2002 LPG G Van Service Manual Supplement Page 171 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Ignition System Checks Note LPG being a gaseous fuel requires higher secondary ignition system voltages for the equivalent gasoline operating conditions Check for the proper ignition voltage output with J 26792 or the equivalent Verify that the spark plugs are correct Check the spark plugs for the following conditions Wet plugs Cracks Wear Improper gap Burned electrodes Heavy deposits Check for bare or shorted ignition wires Check for moisture in the distributor cap if applicable Check for loose ignition coil connections Important 1 If the engine starts but then immediately stalls remove the CKP sensor 2 Check for improper resistance or faulty connections 3 Check the Crankshaft Position CKP sensor resistance and connections Refer to Enhanced Ignition System in the GM G Van Service Manual Engine Mechanical Checks Important The AF system works on a fumigation principle of fuel introduction and is more sensitive to intake manifold leakage than the gasoline fuel supply system e Check for the following Vacuum leaks Improper valve timing Low compression Bent pushrods Worn rocker arms Broken or weak valve springs Worn camshaft lobes Ref e Check the intake and exhaust manifolds for casting flash Exhaust
126. e barometer reading by 3 4 The result indicates the correct BARO value for your area This step tests the MAP sensor s ability to correctly indicate engine vacuum This step indicates this sensor is currently functioning correctly If you were sent to this diagnostic procedure from other service information return to that procedure now DTC P0106 DTC 32 MAP System Performance Did you perform the Alternative Fuels AF Powertrain On Board Diagnostic OBD System Check Turn the ignition ON with the engine OFF Using the scan tool establish communication with the AF ECM Observe and record the MAP sensor kPa display Does the MAP sensor data parameter indicate MAP pressure greater than the specified value Remove the MAP sensor from the engine vacuum source Leave the MAP sensor connected to the engine harness Go to AF Powertrain OBD System Go to Step 2 nee 75 kPa altitude 95 kPa sea level Go to Step 3 Go to Step 8 Connect a hand vacuum pump to the MAP sensor Observe the MAP sensor kPa as you SLOWLY apply vacuum 1 Hg at a time Observe the MAP sensor data parameter Observe the MAP sensor display for a skip or jump while increasing the vacuum up to 20 Hg Did you observe a skip or a jump Go to Step 8 Go to Step 4 2002 LPG G Van Service Manual Supplement Page 59 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Value s ves mo Observe the MAP sensor kPa display with 20
127. e bolts to 12 Nem 9 lb ft Install the engine cover and connect the retaining straps Connect the electrical connectors for the lighter accessory plug and storage compartment lamp Install the center consol Install the center consol mounting hardware Install the IP lower trim panel to the IP Install the air cleaner housing Connect the MAF and IAT sensor electrical connectors Connect the negative battery cable 2002 LPG G Van Service Manual Supplement Page 192 QUANTUM PROPANE FUEL SYSTEM Engine v Control ECM LIT Module Bracket E ECM ALTERNATIVE FUEL ENGINE CONTROL 2 Snap the AF ECM in the bracket MODULE AF ECM REPLACEMENT 3 Install the coolant surge tank 4 Connect the negative battery cable Removal Procedure 1 Disconnect the negative battery cable PROPANE FUEL SYSTEM 2 Remove the coolant surge tank INSPECTION 3 Un snap the AF ECM from the bracket 4 Disconnect the two 2 AF ECM electrical Inspect the propane fuel system hoses and vacuum connectors lines for cracks wear or other damage Replace if necessary Inspect the propane fuel system Installation Procedure brackets for cracks deformation or other damage Replace if necessary Inspect all fasteners and 1 Connect the two 2 AF ECM electrical service as necessary connectors 2002 LPG G Van Service Manual Supplement Page 193 Website 9 2 03
128. e for at least 30 seconds The engine operating temperature the HO2S will produce a coolant temperature must be greater than 50 C voltage in relation to the oxygen content of the AND the mass air flow above 4 4 gms sec for at exhaust The HO2S requires an operating least 30 seconds for the AF ECM to determine temperature of 600 F 360 C to produce voltage the HO2S is at operating temperature The HO2S will produce more voltage when the e The AF ECM is operating in closed loop fuel exhaust is rich and less voltage when the exhaust is control lean The HO2S operating range is around 0 10 volts 100 mV to 1 volt 1000 mV The PCM Conditions for Setting the DTC supplies a bias or reference voltage to the HO2S This bias voltage is around 450 mV The AF ECM monitors an HO2S signal voltage of M less than 0 08 volts 78 mV for 15 seconds This DTC is used to indicate an HO2S signal voltage continuously that is below the normal operating range of the sensor This DTC is a type B DTC 2002 LPG G Van Service Manual Supplement Page 102 Website 9 2 03 Action Taken When the DTC Sets The AF ECM will control fuel trim based upon the Bank 2 Sensor 1 signal If a Bank 2 Sensor 1 DTC sets the AF ECM will operate in open loop fuel control A first failure of this DTC will NOT illuminate the MIL and will store as Last Test Failed but not as History The AF ECM will illuminate the MIL and store the DTC as History TWO consecutive drive trips
129. e running at part throttle in closed loop If the failure is induced the HO2S Bank 2 Sensor 1 signal voltage reading changes from its normal fluctuating voltage above 600 mV and below 300 mV to a fixed value around 450 mV This may help isolate the location of the malfunction e Never solder the HO2S wires For proper wire and connector repair refer to Wiring Repairs in Engine Electrical Test Description The number s below refer to the step numbers on the diagnostic table 2 This step determines if proper sensor activity us present When in closed loop fuel control the 2002 LPG G Van Service Manual Supplement Page 136 QUANTUM PROPANE FUEL SYSTEM HO2S voltage should rapidly swing above the bias voltage 6 This step determines if the PCM and the high and low circuits between the PCM and HO2S connector are operating properly 9 This step determines if the HO2S heater circuit operates correctly up to the HO2S connector 10 This step determines if the proper circuit resistance exists between the HO2S low circuit and the PCM ground 15 This step determines if the proper circuit resistance exists between the HO2S low circuit and the PCM ground with a cold sensor A loose HO2S or poor cold thread to exhaust electrical contact will cause higher resistance when the HO2S is cold Although 500 ohms is allowed typical resistance should be less than 50 ohms DTC P0154 DTC 63 HO2S Insufficient Activity Bank
130. ebsite 9 2 03 QUANTUM PROPANE FUEL SYSTEM step ton w ves w Using the scan tool clear the DTC information from BOTH control modules Operate the vehicle under the Conditions for Running the DTC Using the scan tool parameter DTC STATUS ensure that this DTC runs Did this DTC RUN and PASS System OK Go to Step 2 2002 LPG G Van Service Manual Supplement Page 101 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM DTC P0131 DTC 44 HO2S Circuit Low Voltage Bank 1 Sensor 1 Un em Te we Monae ras 1 1 Control 1 Engine Control Underood Signal ow Modue PCM Sen BISI Module AF ECM Fuse Relay lc ae ee a Pa A NI aos dl Center 69 29 NCTA BLU 6 C001 CLR PNK 539 PPL WHT 1665 HO2S Bank 2 TAN WHT Sensor 1 PPLWHT PNK 1665 C004 TAN WHT TAN WHT 027 TANAWHT 1653 A Ignition Power HO2S Heated Oxygen Sima S Sensor HO2S Bank 1 Sensor 1 Ground HO2S Bank A7 Sensor 1 6103 Circuit Description Conditions for Running the DTC The heated oxygen sensor is used to determine the e Engine speed is greater than 400 RPM oxygen content of the engine s exhaust The oxygen e Engine coolant temperature is greater than content indicates when the engine is operating lean 160 F 70 C or rich When the engine is operating lean the e The oxygen sensor has been at operating exhaust will have more oxygen content Once at temperatur
131. ecks e Check the Engine Coolant Temperature ECT sensor with the scan tool Compare the engine coolant temperature with the ambient air temperature on a cold engine IF the coolant temperature reading is more than 5 degrees greater or less than the ambient air temperature on a cold engine check for high resistance in the coolant sensor circuit Refer to DTC P0118 ECT Sensor Circuit High Voltageor DTC P1115 ECT Sensor CKT Intermittent High Voltage in the GM G Van Service Manual e Check the Crankshaft Position CKP sensor e Check the Mass Air Flow MAF sensor Fuel System Checks Important A closed LPG manual fuel shut off override valve will create an extended crank OR no start condition e Verify the excess flow valve in the fuel tank lock off valve is not tripped e Check the fuel pump relay for proper operation The fuel pump relay circuit supplies a voltage signal to the fuel tank lock off lock off LPL solenoids Refer to Fuel Pump Circuit Diagnosis in the GM G Van Service Manual Check mixer module assembly for proper installation and leakage Verify proper operation of the low pressure lock off solenoid Verify proper operation of the fuel tank lock off solenoid Verify proper operation of the fuel control solenoid Verify proper operation of the idle control solenoids Check for air intake system leakage between the mixer and the throttle body Check the coolant level If coolant is added bleed the cooling system using th
132. ect a scan tool 2 Set up the scan tool with the proper vehicle identification prior to turning the ignition ON Establish communication with the PCM 150 mV Turn the ignition ON leaving the engine OFF and as quickly as possible observe and record the HO2S voltage for the sensor that applies to this DTC Observe the HO2S voltage for two minutes Does the HO2S voltage increase or decrease from the initial voltage by at least the specified value Go to Step 3 Go to Step 6 Allow the HO2S voltage to stabilize Use the scan tool to observe and record the current HO2S voltage from the PCM Use the scan tool to establish communication with the AF ECM 45 mV Use the scan tool to observe and record the current voltage from the AF ECM for the HO2S B1 S1 Does the AF ECM indicate the same HO2S voltage as the PCM plus or minus the specified value Go to Step 4 Go to Step 14 Go to Step 18 Go to Step 5 Go to Go to AF DTC List Intermittents Go to Step 7 Go to Step 8 2002 LPG G Van Service Manual Supplement Page 121 The fault is not present Refer to Diagnostic Aids Are any DTCs stored that have not been diagnosed Turn the ignition OFF Disconnect the HO2S B1 S1 connector Connect an un powered test lamp between the HO2S heater ignition feed and ground circuit terminals engine harness side Turn the ignition ON leaving the engine OFF Does the test lamp illuminate The condition that set this DTC is not p
133. ed proceed to the applicable DTC table in the order stated in the OBD System Check Always diagnose ANY PCM codes that are present before beginning this diagnostic procedure Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Check the following items e Fuel pressure The ECM can compensate for small increases in fuel pressure However large increases in fuel pressure may set a DTC e Faulty Fuel Control Solenoid FCS e Vacuum leaks in the fuel control valve hoses e False rich indication due to silicon contamination of the HO2S This will be accompanied by lean driveability conditions and a powdery white deposit on the sensor e Faulty HO2S Bank 2 Sensor 1 If the HO2S Bank 2 Sensor 1 is internally shorted the HO2S Bank 2 Sensor 1 voltage displayed will be over 1V Try disconnecting the HO2S Bank 2 Sensor 1 if the displayed voltage goes from over 1000 mV to around 450 mV replace HO2S Bank 2 Sensor 1 e Never solder the HO2S wires Test Description The numbers below refer to the step numbers on the diagnostic table 3 An HO2S contaminated by silicon will have a white powdery deposit on the portion of the HO2S that is exposed to the exhaust stream The usual cause of the silica contamination is the use of unapproved silicon RTV engine gasket material or the use of silicon based sprays or fluids within the engine If the cause of this contamination is not corrected the replacement HO2S will also become contami
134. eeeee ener nennen nnn 187 Pressure Relief Device PRD Tank Replacement sss 187 Liquid Level Gauge Tank Replacement eeeeeeeeeeenenen nnn 188 Liquid Level Gauge Fill Valve Replacement eere 188 Fuel Line Replacement eeeeeseseeeeeeeene enema nnmnnn nn nnn nnn 188 Propane Fuel Filter Replacement eeeeeeeeee eene 189 Low Pressure Lock off LPL Replacement Underhood 190 Low Pressure Regulator LPR Replacement eene 191 Fuel Control Solenoid FCS Replacement SEENEN ENNEN ENEE 191 Idle Control Solenoid ICS Repnlacement kee ENEE EEN ENEE ENEE 192 Fuel Mixer Outlet Elbow Cover Assembly Replacement 192 Engine Control Module ECM Replacement eene 193 Propane Fuel System Inspection eeeeeeeeeeeeeeeneeen enne nennen nnne nnne nnn nnn 193 2002 LPG G Van Service Manual Supplement Page 4 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM VEHICLE APPLICATION The QUANTUM propane system is designed for the 2002 LPG G Van with the 5 7L V 8 RPO L31 PROPANE FUEL SYSTEM CAUTIONS CAUTION Do not smoke carry lighted tobacco or use a lighted flame of any type when working on or near any fuel related component Highly flammable air fuel mixtures may be
135. eeeeeeeeeeseeeenseeeeeeeseseeeeeeeeeeeensessaeeeeeeseeeeees 5 Description and Operation ccceeeececeeeeeeeeeeeeeeeeeeeeeseeeeeeeeeeeeeeeeeseeeeeseseeeeeseeeeeeeseeseeeeeeesenenees 5 Propane Fuel System NEESS a a 5 EPGi Fuel tank nicas is A dias i n 5 Fuel Tank LOCK O tc tapon 5 Underhood Low Pressure LOCK Off ooooncoonnccccnccoonncconncconnnconnncnnnnnonanennnnnnnnnrrnnnennnanes 6 Low Pressure Regulator LPR ooomccoonncoonnccccnccconncccnncnonnncnnnnnnnnrnonanennnnrnnanrrnnrnenanes 6 Fuel Mixer iii in 6 Alternative Fuel Engine Control Module AF ECM eeeeeseeee 6 Control SS Ee e EE 6 System Operation Features cccccceeeececeeeeeeeeeeeeeeeeeeeeeeeeeeeeeseeeeeeeseeeeeeeeeeeeeeeeesseneeees 7 Maintenance Schedule eelleeeseeeeiueeeiieseeieeeiiee ness EEN ENEE REENEN nnn nnns 7 Normal Maintenance Replacement Parts uses 8 Diagnostic Information and Procedures eeeesseseeeeeeeeee enne nennen nnne nnn KEEN 9 Engine Controls SchematiCS oocccoonnnncccnonnnnncnonnnnnnnnnnnnnnnnnnnn nr nnnnr rre nnn nnn 9 Connector End Views sa 17 AF Engine Scan Tool Data LiSt ooonncccnnnnncncncnnncncnnnnnnnnnnnnnnnnnnnnn rr rre 23 AF ECM Output Driver Data eese enne nnne 23 AF Diagnostic Trouble Code DTC List oooncconncccnncnonancnonnnnonnnnnnnncnancncnnnrennnrnenanes 24 Alternative
136. en the circuit splice and the AF ECM connector Inspect for proper terminal contact at the AF ECM connector Repair wiring or terminal as necessary Was a wiring or terminal repair necessary Go to Step 18 Go to Step 17 Connect a test lamp between the ignition feed circuit terminal and the ground circuit terminal of the MAF sensor connector Is the test lamp illuminated Go to Step 14 Go to Step 11 Connect a test lamp between the ignition feed circuit terminal of the MAF sensor connector and a known good ground Is the test lamp illuminated Go to Step 13 Go to Step 12 2002 LPG G Van Service Manual Supplement Page 52 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Go to Step 18 Goto Step 15 Go to Step 18 Go to Step 18 Go to Step 18 System OK Go to Step 2 2002 LPG G Van Service Manual Supplement Page 53 Value s Repair the cause of no MAF sensor voltage Possible causes include the following An open ignition fuse An open or shorted to ground blown fuse ignition feed circuit A shorted to ground blown fuse component that shares the MAF sensor ignition feed circuit Repair wiring or replace components as necessary Is the repair complete Repair the open MAF sensor ground circuit Is the repair complete 1 Inspect the MAF sensor connector for proper terminal contact 2 Repair terminal as necessary Was a connector terminal repair made Replace the MAF sensor Refer to MAF Senso
137. enoid FCS Replacement Check the fuel hose between the LPR and the ICS for kinks or obstructions Was a problem found and repaired Go to Step 26 Go to Step 20 Go to Step 22 Ke Is the action complete Go to Step 22 ve Return the fuel system to normal operating condition Observe the scan tool MAF reading Raise the engine speed to approximately 2500 20 to 80 RPM or greater than 28 g s MAF Observe the duty cycle reading of the FCS Is the FCS duty cycle within the specified range Go to Step 26 Go to Step 23 Check all vacuum hoses and mixer connections for leakage Goto Step 26 Goto Step 24 Is the action complete Go to Step 26 The AF fuel control system is operating normally Refer to Symptoms Diagnosis Disconnect all test equipment If you were sent to this routine by another diagnostic chart return to the previous diagnostic procedure i 2 Is the action complete System OK 2002 LPG G Van Service Manual Supplement Page 46 Was a problem found and repaired Replace the fuel mixer Refer to Fuel Mixer Replacement Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Step 363 Action Values Yes 1 Disconnect all test equipment 2 Start the engine 3 Using SNOOP or equivalent leak check any fuel system repairs made Is the action complete System OK Website 9 2 03 2002 LPG G Van Service Manual Supplement Page 47 QUANTUM PROPANE FUEL SYSTEM LPG Fuel Sen
138. ent in Engine Controls in the GM G Van service manual Is the replacement complete Using the scan tool clear the DTC information from BOTH control modules Operate the vehicle under the Conditions for Running the DTC Using the scan tool parameter DTC STATUS ensure that this DTC runs Did this DTC RUN and PASS Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM DTC P0107 DTC 34 MAP Sensor Circuit Low Voltage Circuit Description The manifold absolute pressure MAP sensor is a pressure sensor The PCM supplies about 5 volts on the MAP sensor reference voltage circuit The PCM also supplies a ground circuit to the MAP sensor When manifold vacuum is low the MAP signal voltage rises to near 4 5 volts As manifold vacuum increases the MAP signal voltage drops to around 1 0 volt The PCM and the AF ECM monitor MAP signal voltage and determine the vacuum within the intake manifold The vehicle also uses the MAP sensor to determine the barometric pressure when the ignition switch is turned ON and the engine is NOT cranked This BARO reading may also be updated whenever the engine is operated at wide open throttle This DTC is used to indicate a MAP sensor signal voltage that is below the normal operating range of the sensor DTC is a type B DTC Conditions for Running the DTC The engine speed is greater than 500 RPM DTCs P0121 P0122 or P0123 are not set Website 9 2 03 Rl e M 7 powertrain e E Alte
139. ep8 Goto Step 10 ES Will the engine rev to 2500 RPM WE Goto Step 7 Goto Step 11 20 to 80 Observe the scan tool MAF reading Raise the engine speed to approximately 2500 RPM or greater than 28 g s MAF Observe the duty cycle reading of the FCS Is the FCS duty cycle within the specified range Goto Step25 Goto Step 13 1 With the engine idling observe the duty cycle of the ICS on the scan tool 80 Is the ICS duty cycle ABOVE the specified range Go to Step 9 Go to Step 13 2002 LPG G Van Service Manual Supplement Page 44 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Value s ve Ne Using a DVOM backprobe the ICS electrical connector terminals 2 Observe the duty cycle of the ICS 80 Is the ICS duty cycle ABOVE the specified range Go to Step 19 Go to Step 12 Observe the scan tool MAF reading Raise the engine speed to approximately 2500 RPM or greater than 28 g s MAF 20 to 80 Observe the duty cycle reading of the FCS Is the FCS duty cycle within the specified range Goto Step 12 Go to Step 11 Turn the engine OFF Go to Step 26 Goto Step 17 Disconnect the ECM connector C001 Disconnect the FCS electrical connector Check the FCS ground circuit in terminal B LT GRN for continuity to the ECM connector Check the FCS ground circuit in terminal B LT GRN for short to ignition power or ground Was a problem found and repaired Connect the positive lead of the DVOM to an ignitio
140. er THREE consecutive drive trips that the DTC runs and passes The History status will clear after FORTY consecutive WARM UP cycles with NO failures of ANY DTC All information can be cleared using a scan tool Interruption of Control Module AF ECM PCM power and ground MAY clear DTC information Clearing DTC information with this method is inconsistent and should not be performed Diagnostic Aids Fault Not Present Fault Not Present indicates the condition that caused the DTC to set is intermittent and not currently present Refer to Intermittents in Symptom diagnosis for additional information If any additional DTCs were stored proceed to the applicable DTC table in the order stated in the OBD System Check Preliminary Checks Check the following conditions Low or empty LPG fuel tank For proper LPG fuel system operation liquid fuel is required at the LPR inlet If the fuel level becomes so low that fuel vapor is delivered to the LPR inlet the air fuel mixture will be lean and the MIL may Website 9 2 03 illuminate Also the vehicle will start and idle normally but hesitate and stumble under load If the DTC is current verify that the fuel tank is at least 1 4 full If the DTC is stored in history verify with the operator if the vehicle has recently been run low or out of fuel A poor connection or a damaged harness Backed out terminals Improperly formed or damaged terminals Poor terminal to wire connection D
141. er fuse other DTCs may be set Did you complete the repair Repair the high resistance between the HO2S low circuit and the PCM ground circuit Possible causes include the following A faulty HO2S connector terminal contact An open sensor harness low circuit requires HO2S replacement A sensor harness low circuit with high resistance requires HO2S replacement A faulty PCM ground connection A high PCM ground circuit resistance An ungrounded exhaust system Did you complete the repair 1 Inspect for exhaust system leaks upstream of the suspect HO2S The leak may be very small and is typically within 12 inches of the HO2S 2 Repair the exhaust as necessary Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Sep on Vaw Ye Ne Inspect the oxygen sensor signal and low circuit for continuity between the AF ECM connector terminals and the oxygen sensor connector terminal Inspect these circuits for shorts to other circuits or to ground Ensure the oxygen sensor PCM and the AF ECM connectors are disconnected before testing the circuits 3 Repair the wiring as necessary Go to Step 22 Goto Step 18 Go to Step 22 Go to Step 22 Go to Step 20 Was a wire repair made Replace the AF ECM Refer to AF ECM Replacement Is the replacement complete Perform the AF Fuel System diagnosis and return to this step Refer to AF Fuel System Diagnosis Was an LPG fuel system problem found and repaired Important
142. erminals engine harness side 3 Turn the ignition ON leaving the engine OFF Does the test lamp illuminate Go to Step 10 Go to Step 12 Turn the ignition OFF Reconnect the HO2S connector Disconnect the PCM connector containing the HO2S low circuit and the PCM connector containing the PCM ground circuits 500 ohms Using a DVOM measure the resistance between the HO2S low circuit terminal and one of the PCM grounds Is the resistance less than the specified value Go to Step 14 Go to Step 13 2002 LPG G Van Service Manual Supplement Page 138 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Sep Ado Vaws Ye mw Repair the circuit that measured high resistance Go to Step 17 Go to Step 22 o Was an exhaust system repair made Go to Step 22 Goto Step 15 1 Allow the engine to cool to ambient temperature 2 Using a DVOM re measure the resistance between the HO2S low circuit terminal and a 500 ohms PCM ground circuit terminal Is the resistance less than the specified value Goto Step 19 Goto Step 16 Remove the HO2S from the exhaust Clean the HO2S mounting threads Apply HO2S safe anti seize compound to the sensor threads Tighten the HO2S to the proper torque Refer to HO2S Replacement in the GM G Van service 500 ohms manual Using a DVOM measure the resistance between the HO2S low circuit terminal and a PCM ground circuit terminal Is the resistance less than the specified value
143. ertrain OBD System Go to Step 2 Check ES Was DTC P0601 58 retrieved from the AF ECM Go to Step 3 Go to Step 5 1 Verify that the follow connections to the AF ECM are clean and tight e Battery Power e Ignition Power e Ground 2 Check loose or corroded connections at the ECM connector Was a problem found and corrected Go to Step 6 Go to Step 4 Replace the AF ECM Refer to AF ECM Replacement Is the replacement complete Go to Step 5 Go to the applicable DTC Were any other DTCs set in the AF ECM table System OK 1 Start and run vehicle 2 Check to see if the MIL still illuminates Did the diagnostic run and pass Go to Step 7 Go to Step 2 Go to the Are any ECM or PCM DTCs stored that have not applicable DTC been diagnosed table System OK 2002 LPG G Van Service Manual Supplement Page 163 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM DTC P1215 DTC 27 Control Module Output Circuits Pipe setae a nae Sie Sian at Hot in Run and Start 1 i H7 ECM 1 F5 LPG Underhood Fuse Fuse Fuse Relay J8 O 20 G6 9 20A Center To OEM Components K XC004 To AF C004 S003 EGM RED 920 19 Fuel 439 ORN 1340 o Fue Sending 012 S004 Unit A Ignition Relay Idle Control Solenoid ICS 920 BLK 450 001 To Wait To 007 Drive Light and UB LPL DK GRN 903 BLK 450 2 Alternative Fuel Engine Control Ground f 3 Module Back of Right Cylinder Head AF ECM Circuit Description The
144. es the condition that caused the DTC to set is intermittent and not currently present Refer to Intermittents in Symptom diagnosis for additional information If any additional DTCs were stored proceed to the applicable DTC table in the order stated in the OBD System Check Test Description The numbers below refer to the step numbers on the diagnostic table 2 As the heater warms the oxygen sensor to operating temperature the HO2S will output a voltage in relation to the amount of oxygen in the exhaust With the ignition ON and the engine OFF the exhaust usually contains a high oxygen content With the engine OFF the HO2S voltage will usually decrease from the initial bias voltage due to the high oxygen content This step test for proper HO2S heater ignition power and ground supply This step tests for proper PCM and signal circuit operation DTC P0135 DTC 43 HO2S Heater Performance Bank 1 Sensor 1 Sep Ao LL Ve Ye Ne Did you perform the Alternative Fuels AF Powertrain On Board Diagnostic OBD System Check Website 9 2 03 Go to AF Powertrain OBD System heck Go to Step 2 SES 2002 LPG G Van Service Manual Supplement Page 120 QUANTUM PROPANE FUEL SYSTEM Sep o Aon Values Ye No 7 Important The HO2S must be cool before proceeding with this diagnosis The ignition must remain OFF for at least on half hour before proceeding with the diagnosis 1 Conn
145. estriction Check for air leaks at all the mounting areas of the intake manifold sealing surfaces Check for proper installation of the mixer module assembly Check for air leaks at the mixer assembly Check the ignition wires for the following conditions Cracking Hardness Proper routing Carbon tracking Check the wiring for the following items Proper connections pinches or cuts The following symptom tables contain groups of possible causes for each symptom The order of these procedures is not important If the scan tool readings do not indicate the problems then proceed in a logical order easiest to check or most likely to cause first To determine if a specific vehicle is using a particular system or component refer to the Control Module Wiring Diagrams in the GM G Van Service Manual for an application 2002 LPG G Van Service Manual Supplement Page 167 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Intermittents DEFINITION The problem may or may not turn ON the Malfunction Indicator Lamp MIL or store a Diagnostic Trouble Code DTC Preliminary Checks Refer to Important Preliminary Checks Do not use the DTC tables If a fault is an intermittent the use of the DTC tables may result in the replacement of good parts Faulty Electrical Connections or Faulty electrical connections or wiring can cause most intermittent problems Wiring Check the suspected circuit for the following conditions Faulty fuse or
146. failure or an intermittent condition 3 This step determines if the ECM is receiving the CKP sensor pulses 6 This step checks the CKP sensor signal circuit for any unusual loading conditions If the ECM is not receiving a signal and no circuit faults can be found The PCM is not outputting a tachometer signal and should be diagnosed DTC P0336 DTC 41 CKP Sensor Circuit Performance Sep Age Values Yes No Go to AF Powertrain OBD System heck Go to Step 2 SES Was the Alternative Fuels AF Powertrain On Board Diagnostic OBD System Check performed Start the vehicle Does the vehicle start and continue to run Go to Diagnostic Aids Go to Step 3 Website 9 2 03 2002 LPG G Van Service Manual Supplement Page 156 a HUANTUMT PROPANE FUEL SYSTEM PROPANE FUEL SYSTEM Go to Step 5 Go to Step 4 Al Go to Step 8 Goto Step 6 1 Clear the DTC 2 Operate the vehicle within the conditions for setting this DTC as specified in the supporting text 3 Check to see if the MIL still illuminates Go to Did the diagnostic run and pass Diagnostic Aids Go to Step 7 Sup Aum Vale Yes We 1 Turn OFF the ignition 2 Backprobe engine speed signal TACH circuit at ECM connector C002 3 Connect a DVOM set to read AC voltage between the CKP sensor signal circuit and a known good ground 4 Crank the engine Is voltage detected while the engine is cranking 1 Turn OFF the ignition 2 Disconnec
147. ff its seat Approximately 0 5 psi 13 8 water column lifts the valve to the top of its travel in full open position Lowered pressure communicated to the top of the diaphragm varies with engine speed and position of throttle valve opening The air valve assembly measures the air flow into the engine by Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM moving precisely in response to the demands of the engine and throttle valve position The controlled pressure drop of 0 2 to 0 5 psi 6 to 13 8 water column set up by the metering spring provides the signal or force necessary to draw fuel into the air stream within the carburetor The gas metering valve is attached to the air valve assembly and is shaped to admit the correct amount of fuel from the gas jet to mix with incoming air at any opening of the air valve ALTERNATIVE FUEL ENGINE CONTROL MODULE AF ECM The alternative fuel engine control module AF ECM controls the propane fuel system The AF ECM monitors various engine and vehicle functions to provide the correct amount of fuel under all operating conditions This provides excellent driveability and fuel economy while maintaining reduced exhaust emission levels CONTROL SOLENOIDS FUEL CONTROL SOLENOID FCS An electrically actuated control solenoid used to trim fuel mixtures by controlling the pressure on top of the LPR secondary diaphragm During closed loop operation the ECM commands a duty cycle to the fuel co
148. fitting at the fill valve to relieve the fuel pressure Disconnect the fuel line from the fill valve Remove the fill valve cover Remove the fill valve mounting nut and the fill valve Installation Procedure Install the fill valve and the mounting nut e Tighten the nut to 54 Nem 40 lb ft Install the fill valve cover Connect the fuel fill line to fill valve e Tighten the fitting to 47 Nem 35 Ib ft Connect the negative battery cable FUEL LINE FILL VALVE TO TANK REPLACEMENT Removal Procedure oom Disconnect the negative battery cable Remove the fuel tank cover bolts and the cover Slowly open the fuel line fitting at the fill valve to relieve the pressure Remove any clips clamps or brackets from the fuel line Disconnect the fuel line at the fill valve Disconnect the fuel line at the tank Remove the fuel line Installation Procedure Install the fuel line Connect the fuel fill line at the tank e Tighten the fitting to 47 Nem 35 Ib ft Connect the fuel fill line to the fill valve e Tighten the fitting to 47 Nem 35 Ib ft 2002 LPG G Van Service Manual Supplement Page 184 4 Install any clips clamps to brackets to the fuel line 5 Connect the negative battery cable 6 Start the vehicle and leak check the propane fuel system at each serviced fitting 7 Install the fuel tank cover and bolts e Tighten the bolts to 22 Nem 16 lb ft Website 9 2 03 QUANTUM PROPANE FUE
149. ft 4 Install any clips clamps to brackets to the fuel line 5 Connect the negative battery cable 6 Start the vehicle and leak check the propane fuel system at each serviced fitting LPG FUEL FILTER TO UNDERHOOD LOCK OFF Removal Procedure Relieve the propane fuel system pressure Refer to Propane Fuel System Pressure Relief Disconnect the negative battery cable Remove the IP lower trim panel from the IP Remove the center consol mounting hardware Disconnect the electrical connectors for the lighter accessory plug and storage compartment lamp oak wf Website 9 2 03 7 8 9 10 11 Remove the center consol Release the engine cover retaining straps and remove the cover Remove any clips clamps or brackets from the fuel line Disconnect the fuel line at the underhood LPL Disconnect the fuel line at the filter Remove the fuel line from the vehicle Installation Procedure 1 2 3 8 9 10 11 Install the fuel line in the vehicle Connect the fuel line at the filter e Tighten the fitting to 37 Nem 27 lb ft Connect the fuel line at the underhood LPL e Tighten the fitting to 37 Nem 27 lb ft Install any clips clamps to brackets to the fuel line Connect the negative battery cable Start the vehicle and leak check the propane fuel system at each serviced fitting Install the engine cover and connect the retaining straps Connect the electrical connectors for the
150. fuel level becomes so low that fuel vapor is delivered to the LPR inlet the air fuel mixture will be lean and the MIL may illuminate Also the vehicle will start and idle normally but hesitate and stumble under load If the DTC is current verify that the fuel tank is at least 1 4 full If the DTC is stored in history verify with the operator if the vehicle has recently been run low or out of fuel Fault Not Present Fault Not Present indicates the condition that caused the DTC to set is intermittent and not currently present Refer to Intermittents in Symptom diagnosis for additional information If any additional DTCs were stored proceed to the applicable DTC table in the order stated in the OBD System Check Test Description The numbers below refer to the step numbers on the diagnostic table 2 As the heater warms the oxygen sensor to operating temperature the HO2S will output a voltage in relation to the amount of oxygen in the exhaust With the ignition ON and the engine OFF the exhaust usually contains a high oxygen content With the engine OFF the HO2S voltage will usually decrease from the initial bias voltage due to the high oxygen content 6 This step test for proper HO2S heater ignition power and ground supply 7 This step tests for proper PCM and signal circuit operation DTC P0155 DTC 62 HO2S Heater Performance Bank 2 Sensor 1 Sep Aon ei Ye No Did you perform the Alternative Fuels A
151. gh EC 1 28 SES nove 8 Aitemative Fuel AF Enable 2002 LPG G Van Service Manual Supplement Page 18 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM In line Harness Connector C003 Connector Part e 12052848 AF Harness Side Connector Part 12124107 OEM Harness Side Information 6 way Metri Pack Sealed 150 Information 6 way Metri Pack Sealed 150 Series BLK Series BLK Wire Circuit Wire Circuit ml com Ne runcton Pm cor Ne Funeton Fuel Pump Power WC ee se po Noted s Be e eee Not Used C 918 Fuel Gauge Signal From Fuel Gauge Signal From POM POM BLK 918 Fuel Gauge Signal BLK 918 Fuel Gauge Signal MIL Output To MIL Lamp MIL Input From PCM In line Harness Connector C301 Connector Part 12110751 OEM Harness Connector Part 12110753 AF Harness Information e 7 way F Metri Pack 280 Series Information 7 way M Metri Pack 280 Series BLK BLK Wire Circuit Wire Circuit ol ei no nee pin ep o mel n B PPL 1589 FuelLevelSensor Primary B PPL 1589 Fuel Level Sensor Primary c Bk a0 SVottReterence c Meet D GRY 474 5VoltReference wNB6 D Notused O eom A Se o RT Signal w NB6 F BK 47 LowRefeeme w NB F nouse G GRY 120 FuelPumpSupplyVoltage G Moise 2002 LPG G Van Service Manual Supplement Page 19 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM In l
152. gine Temperature Sensor ECT Sensor Circuit Low Voltage po uc amic hay oye MIT CP x nie SS O egy Powertrain 1 Alternative Fuel Control i Engine Control 1 ECT Sensor IAT Sensor 5 Volt 5Volt Module 1 ECT Sensor IAT Sensor 5Volt A Module 1 Signal Signal Reference Reference PCM h Signal Signal Reference 1 AF ECM 74 C1 BLU 25 C2 RED 8 48 C1 BLU 12 N ee 2134 29 C002 BLU YEL 410 GRY 2704 TAN 472 YEL 410 TAN 472 GRY 2701 A B D YEL 017 410 TAN YEL 410 018 472 TAN 472 GRY 022 2704 GRY 2704 A C Coon Temperature Throtts cise Position Pressure TP MAP Sensor Sensor A B A B LT GRN 432 LT GRN 417 SES ORN BLK 469 S020 ORN BLK S021 BLK 2761 BLK 2760 BLK 2752 Ris 469 Sun DK BLU ORN BLK 469 Ne S T lada ee Get LT GRN 432 ORN C1 c2 C1 C1 pkBLU 417 HP ir GRN 422 80 de BLU 57 RED 60 BLU 24 C2 RED 54 BLU 32 C2 RED 27 y 728 VJ 44 d C002 BLU 1 Sensor EE Sensor geren TP Sensor SE Sensor MAP Sensor d TPSenso Sensor MAP Sensor Ground Ground Ground Signal Ground Signal H Signal Ground Signal RACCONTARE tue Ve IE aM Powertrain Control Module PCM Alternative Fuel Engine Control Module AF ECM Circuit Description Conditions for Running the DTC The Engine Coolant Temperature ECT sensor is a e The engine has been running longer than 5 thermistor The ECT thermistor has high resistance Seconds when cold and low resi
153. h frequency signal 7 This step determines if an external source is inducing a high frequency to the MAF signal circuit DTC P0103 DTC 37 MAF Sensor Circuit High Frequency se Alen O Vewes Yes We Did you perform the Alternative Fuels AF Powertrain Go to AF Powertrain OBD System Go to Step 2 Check On Board Diagnostic OBD System Check Start the engine Using the scan tool establish communication with the PCM Observe the MAF sensor data parameter Does the MAF sensor data parameter indicate 4 50 kHz Go to Step 5 Go to Step 3 frequency greater that the specified value 1 Using the scan tool establish communication with the AF ECM 2 Observe the MAF sensor data parameter 20 gms sec Does the MAF sensor data parameter indicate airflow greater than the specified value Go to Step 10 Go to Step 4 The fault is not present Refer to Diagnostic Aids Are there any DTCs stored that have not been diagnosed Go to Go to AF DTC List Intermittents 2002 LPG G Van Service Manual Supplement Page 55 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Step Action Value s 1 Disconnect the MAF sensor connector 2 Observe the MAF sensor data parameter with the engine idling 0 0 kHz Does the MAF sensor data parameter indicate frequency greater than the specified value Go to Step 6 Go to Step 8 Turn the ignition OFF Disconnect the AF ECM connectors Start and idle the engine Observe
154. h the engine operating observe the MAP sensor data parameter Does the MAP sensor data parameter indicate MAP voltage greater than the specified value Go to Step 11 Goto Step 6 Remove the jumper Connect a DVOM between the 5 volt reference circuit terminal and ground 4 8 volts Measure the voltage on the 5 volt reference circuit Is the voltage less than the specified value Go to Step 9 Go to Step 7 Inspect the MAP sensor signal circuit for an open or high resistance between the sensor connector and the PCM Inspect for proper terminal contact at both the PCM and MAP sensor connector Repair wiring or terminal contact as necessary Was a wiring terminal repair necessary Go to Step 14 Go to Step 8 Inspect the MAP sensor signal circuit for a short to engine ground or to the sensor ground circuit Disconnect the AF ECM connector C002 to determine if the AF ECM is the cause of the short Repair the wiring as necessary Was a wiring repair made Go to Step 14 Go to Step 12 Inspect the 5 volt reference circuit for an open or high resistance condition between the MAP sensor connector and the PCM Inspect for proper terminal contact at the MAP sensor connector and the PCM Repair wiring or terminal contact as necessary Was a wiring or terminal repair made Go to Step 14 Go to Step 10 2002 LPG G Van Service Manual Supplement Page 63 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Go to Step 12 Value s
155. he fuel line Disconnect the fuel line at the tank Disconnect the fuel line at the union Discard the O ring Remove the fuel line from the vehicle Installation Procedure 1 Install the fuel line in the vehicle 2002 LPG G Van Service Manual Supplement Page 188 QUANTUM PROPANE FUEL SYSTEM 2 Connect the fuel line at the union using a new O ring Lubricate the O ring with petroleum jelly or the equivalent e Tighten the fitting to 37 Nem 27 lb ft 3 Connect the fuel line at the tank e Tighten the fitting to 37 Nem 27 lb ft 4 Install any clips clamps to brackets to the fuel line 5 Connect the negative battery cable 6 Start the vehicle and leak check the propane fuel system at each serviced fitting FRAME UNION TO LPG FUEL FILTER Removal Procedure 1 Relieve the propane fuel system pressure Refer to Propane Fuel System Pressure Relief 2 Disconnect the negative battery cable 3 Remove any clips clamps or brackets from the fuel line 4 Disconnect the fuel line at the filter 5 Disconnect the fuel line at the union Discard the O ring 6 Remove the fuel line from the vehicle Installation Procedure 1 Install the fuel line in the vehicle 2 Connect the fuel line at the union using a new O ring Lubricate the O ring with petroleum jelly or the equivalent e Tighten the fitting to 37 Nem 27 Ib ft 3 Connectthe fuel line at the filter e Tighten the fitting to 37 Nem 27 lb
156. he minimum temperature FUEL QUALITY The LPG fuel system is designed for use with HD5 grade propane Lower grades of propane especially those with high butane content may affect vehicle performance and emissions Also lower grades of propane may contain higher levels of contaminants that can plug the LPG fuel filter Repairs that are the result of system contamination due to poor fuel quality may not be covered under warranty Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM MAINTENANCE SCHEDULE The following maintenance items are specific to the LPG fuel system These items are required in addition to the maintenance items listed in the GM owner s manual The services shown in this schedule should be performed after 120 000 miles 200 000 km at the same intervals 30 000 MILES 50 000 KM o Inspect intake system for vacuum leaks o Replace LPG fuel filter or every 12 months whichever occurs first 3 o Check all vacuum lines and fittings o Check all fuel lines and fittings o Perform ignition system inspection 28 60 000 MILES 100 000 KM o Check intake system for vacuum leaks Replace LPG fuel filter or every 12 months whichever occurs first 3 o Check all vacuum lines and fittings Check all fuel lines and fittings o Replace spark plugs and perform ignition system inspection 28 o Perform mixer air valve service 60 o 90 000 MILES 150 000 KM o Check intake system for vacuum leaks
157. he AF ECM will turn OFF the MIL after THREE consecutive drive trips that the DTC runs and passes e The History status will clear after FORTY consecutive WARM UP cycles with NO failures of ANY DTC e All information can be cleared using a scan tool 2002 LPG G Van Service Manual Supplement Page 164 QUANTUM PROPANE FUEL SYSTEM e Interruption of Control Module AF ECM PCM power and ground MAY clear DTC information Clearing DTC information with this method is inconsistent and should not be performed Diagnostic Aids Fault Not Present Fault Not Present indicates the condition that caused the DTC to set is intermittent and not currently present Refer to Intermittents in Symptom diagnosis for additional information If any additional DTCs were stored proceed to the applicable DTC table in the order stated in the OBD System Check Preliminary Checks Check for the following conditions e Apoor connection a rubbed through wire insulation or a wire that is broken inside the insulation may cause an intermittent problem Inspect harness connectors for the following conditions Backed out terminals Improper mating Broken locks Improperly formed or damaged terminals Poor terminal to wire connection e Physical damage to the wiring harness DTC P1215 DTC 27 Control Module Output Circuits Values Yes mw ua Go to Step 2 E Go to Step 3 i Go to Step 10 Did you perform the Alternative F
158. he fault is not present Refer to Diagnostic Aids Is an operational concern still present Start the engine and allow to warm up until the ECT sensor reading is above 40 C Is the WTD lamp illuminated Test the WTD lamp control circuit between the AF ECM connector terminal and WTD lamp for a short to ground Repair the circuit as necessary Was as circuit repair necessary Test the AF ECM for a short to ground on C002 pin 31 Was a problem found 1 Connect a scan tool 2 While communicating with the AF ECM command the WTD lamp ON Is the WTD lamp illuminated Test the WTD Control circuit between the AF ECM connector terminal and the WTD lamp for an open or short to power Repair the circuit as necessary Was as circuit repair necessary 1 Test the WTD lamp ignition power circuit for a short to ground or an open 2 Repair the circuit as necessary Was a circuit repair necessary Replace the WTD lamp assembly Is the action complete Replace the AF ECM Refer to AF ECM Replacement Is the action complete Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM step ation Value ves e Remove all test equipment Connect any disconnected components fuses etc Using a scan tool clear DTC information from the AF ECM and the PCM Start the engine and operate the vehicle Observe the WTD lamp Observe vehicle performance and driveability After operating the vehicle inspect
159. he fuel vapor hose clamp at the elbow 15 Clamp the coolant hoses to the LPR or drain the radiator 16 Disconnect the coolant hoses from the LPR 17 Remove LPR from the bracket ok wp Disassembly Procedure 1 Loosen the hose clamp and remove the fuel vapor hose from the LPR outlet fitting 2 Remove the LPL from the LPR Assembly Procedure Important e Do not use Teflon tape on any fuel fitting Use a liquid pipe thread sealant when installing fittings 1 Apply Teflon pipe thread sealant to the threads of the LPR inlet fitting 2 Install the LPL to the LPR outlet fitting e Tighten the LPL finger tight plus 1 to 2 turns and place the LPL in the correct orientation 3 Install the fuel vapor hose and clamp to the LPR outlet fitting e Tighten the clamp to 2 Nem 18 Ib in Installation Procedure 1 Position the LPR on the mounting bracket while connecting the fuel vapor hose 2 Install the fuel vapor hose clamp e Tighten the clamp to 2 Nem 18 Ib in 3 Connect the coolant hoses to the LPR 4 Install the LPR to bracket mounting bolts e Tighten the bolts to 12 Nem 9 lb ft 5 Connect the FCS vacuum line to the LPR Website 9 2 03 Connect the ICS vacuum line to the LPR Connect the LPL electrical connector 8 Install the LPL to bracket mounting bolts e Tighten the bolts to 12 Nem 9 lb ft 9 Connect the fuel line to the LPL e Tighten the fitting to 37 Nem 27 lb ft 10 Connect the negative
160. his opens the regulator permitting fuel to flow to the fuel mixer The regulator receives liquid fuel at tank pressure The pressure is reduced in two stages to slightly less than atmospheric In the first stage the pressure is reduced to approximately 2 5 psi Also during this stage the liquid fuel is vaporized by heating the base of the LPR with engine coolant A sponge located in the primary chamber absorbs any liquid fuel and prevents it from entering the secondary chamber In the second stage the vaporized fuel is drawn into the secondary chamber where the pressure is reduced to approximately negative 1 8 inches of water column FUEL MIXER The QUANTUM Model 425 fuel mixer is an air fuel metering device It requires no linkage or idle vacuum line to the intake manifold The mixer is an air valve design utilizing a relatively constant pressure drop to draw fuel into the mixer from cranking to full load The vacuum applied to the air valve working against a spring located on top of the valve correctly positions the air valve to meter the proper amount of fuel for any given engine speed and load The pressure drop that is controlled by the air valve spring provides the force to draw fuel into the air stream The upward movement of the diaphragm controls the fuel flow in the venturi air valve A pressure drop under the air valve of approximately 0 2 psi 6 water column of pressure is required to lift the air valve o
161. hrottle is pressed the TP signal voltage rises to near the supplied 5 volts As the throttle is released the TP signal voltage drops to around 0 6 volts The PCM and the AF ECM monitor the TP signal circuit voltage and determine the angle or opening of the throttle blade This DTC is used to indicate a TP signal voltage that is above the normal operating range of the sensor This is a type B DTC Website 9 2 03 EE powertrain Mt Ne pte ce ies ee Alternative Fuel i Control i Engine Control 1 ECT Sensor IAT Sensor 5 Volt 5Volt Module l ECT Sensor IAT Sensor 5 Volt Module 1 Signal Signal Reference Reference PCM EN ignal Lx Signal ZE __ AF ECM 74 C1 BLU 25 NN C2 RED 8 C1 BLU IRAN BIN 294 C002 BLU YEL 410 GRY 2704 TAN 472 YEL 410 TAN 472 GRY 2701 A B D YEL 017 410 TAN YEL 410 018 472 TAN 472 GRY A 2704 2704 A Engi Intake Ai ee Temperature Throttle Men wod Sensor Position Pressure TP MAP Sensor Sensor A B A B LT GRN 432 LT GRN DK BLU 417 ORN BLK 469 020 ORN BLK 021 BLK 2761 BLK 2760 BLK 2752 D 469 S019 DK BLU ORN BLK 469 A j e BEBE ad d m C005 LT GRN 432 ORN C1 c2 C1 C1 pk BLU 417 P rend 432 80 4 BLU 57 RED 60 BLU 8 24 Ge RED 2 5 4 BLU 32 C2 RED m 27N 77728 Ny 14 d C002 BLU i Sensor Sensor Sensor TP Sensor Sensor MAP Sensor 4 i TP Sensor Sensor MAP Sensor 1 Ground Ground Ground Signal Ground Signal
162. iagnosis for additional information If any additional DTCs were stored proceed to the applicable DTC table in the order stated in the OBD System Check Test Description The numbers below refer to the step numbers on the diagnostic table 2 This step determines if the failure condition affects the PCM 3 This step determines if the failure condition is present 6 This step determines if the proper MAF signal circuit voltage is available from the PCM 10 This step test for proper MAF sensor ignition voltage and ground circuits 11 This step determines if the MAF sensor ignition voltage circuit or the MAF sensor ground circuit is the cause of the condition DTC P0102 DTC 36 MAF Sensor Circuit Low Frequency Sep Ado LL Valet Ye No On Board Diagnostic OBD System Check Did you perform the Alternative Fuels AF Powertrain Go to Step 2 Start the engine Using the scan tool establish communication with the PCM Observe the MAF sensor data parameter Does the MAF sensor data parameter indicate air flow less than the specified value 1 Using the scan tool establish communication with the AF ECM 2 Observe the MAF sensor data parameter Does the MAF sensor data parameter indicate airflow less than the specified value The fault is not present Refer to Diagnostic Aids Are there any DTCs stored that have not been diagnosed Website 9 2 03 Go to AF Powertrain OBD System Check 2
163. ies a bias or reference voltage to the HO2S This bias voltage is around 450 mV This DTC is used to indicate an HO2S signal voltage that is below the normal operating range of the sensor During normal closed loop operation the AF ECM will add fuel richen the mixture when the HO2S indicates a lean exhaust The AF ECM will remove fuel lean the mixture when the HO2S indicates a rich exhaust This oscillation above and below the bias voltage sometimes referred to as activity or Website 9 2 03 TAN WHT B1 1 Hot in Run And Start o p HO2S 1 B1 S1 Underhood Signal Fuse Relay Center 69 PNK 539 PPLWHT 1665 HO2S Bank 2 Sensor 1 PNK Ignition Power HO2S B1S1 Signal Ground HO2S Bank 2 lt Sensor 1 G103 DEE 4 Alternative Fuel 1 Engine Control Module AF ECM 1 Powertrain Control Module PCM t HO2S B1S1 Signal C001 CLR PPLAWWHT PPLANHT 1665 C004 E TAN WHT 1653 TAN WHT 1653 C004 Heated Oxygen Sensor HO2S Bank 1 Sensor 1 switching can be monitored with the HO2S signal voltage The oxygen sensor contains a heater The heater quickly warms the sensor to operating temperature The heater will also maintain operating sensor temperature during extended idle conditions This DTC is used to indicate an HO2S with in active signal voltage This DTC is a type B DTC Conditions for Running the D
164. ill cause roughness stalling and hard starting Refer to EGR System Diagnosis in the GM G Van Service Manual Check the battery cables and ground straps They should be clean and secure Erratic voltage may cause all sensor readings to be skewed resulting in poor idle quality Check the A C refrigerant pressure for being too high or for a faulty high pressure switch Engine Mechanical Check Check the engine for the following Broken motor mounts Improper valve timing Low compression Bent pushrods Worn rocker arms Broken or weak valve springs Worn camshaft lobes 2002 LPG G Van Service Manual Supplement Page 182 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Surges Chuggles DEFINITION The engine has a power variation under a steady throttle or cruise The vehicle feels as if it speeds up and slows down with no change in the accelerator pedal Preliminary Checks Refer to Important Preliminary Checks Be sure the driver understands the Torque Converter Clutch operation Be sure the driver understands the A C Compressor operation Use the scan tool to make sure the reading of the Vehicle Speed Sensor VSS matches the vehicle speedometer This excludes vehicles with electronic transmissions where some variation between the VSS and the speedometer is normal Fuel System Checks Check for Rich or Lean symptom that causes the condition Drive the vehicle at the speed of the complaint Monitoring the oxygen sensors will
165. ine Harness Connector C399 Connector Part e 12129615 AF Engine Side Connector Part e 12110293 AF Tank Side Information e 3 way M Metri Pack 150 Series Information e 3 way F Metri Pack 150 Series BLK BLK Wire Circuit Wire Circuit m e mo mme e e Le B ak 450 Dag B bi 450 Gowo 439 2002 LPG G Van Service Manual Supplement Page 20 Website 9 2 03 Idle Control Solenoid ICS Connector C006 Connector Part Information Connector Part Information Website 9 2 03 12052643 2 way Metri Pack Sealed 150 Series BLK Function 12V Power From Ignition Relay Idle Control Solenoid Signal Duty Cycle 12124037 2 way Metri Pack Sealed 150 seri es BLK 12V Power From Ignition Relay Fuel Control Solenoid Signal Duty Cycle QUANTUM PROPANE FUEL SYSTEM Underhood LPL Connector C008 Connector Part 12052641 Information 2 way Female Metri Pack Scaled 150 Series BLK 12V Power From Ignition Relay 901 LPL Signal Connector Part 12047683 Information 2 way Metri Pack Sealed 150 Series BLK Wire Circuit ml e LL meon GEN 914 Wait To Drive Lamp Signal 0 B LTBLU 450 Ground 2002 LPG G Van Service Manual Supplement Page 21 QUANTUM PROPANE FUEL SYSTEM Tank Lock off Connector C450 Connector Part e 12052641 Information e 2 way Female Metri Pack Sealed 150 Series BLK Wire Circuit ml e no omg B BLK 450 Ground Fuel Sende
166. ine is started and operating the PCM will turn the MIL OFF if no DTCs are set The AF ECM connects into the normal MIL control circuit path and does not affect the PCM of the MIL The AF ECM is connected into the MIL control circuit path to command the MIL ON if a LPG DTC sets Both the AF ECM and the PCM simultaneously test certain DTCs and may illuminate the MIL The IP gauge fuse supplies the positive voltage for the MIL The PCM and or the AF ECM can supply the ground path Website 9 2 03 Alternative Fuel AF BRN WHT C002 BLU C2 RED Powertrain Control Module PCM Alternative Fuel Engine Control Module AF ECM I Fuel AF Enable Enable Diagnostic Aids Using a scan tool the AF ECM output driver data will display AF ECM MIL control status while the engine is cranking or running Test Description The numbers below refer to the step numbers on the diagnostic table 1 The AF Powertrain On Board Diagnostic System Check must be performed before proceeding with this diagnostic table Failure to perform the OBD System Check will result in misdiagnosis With the ignition ON and the engine OFF the PCM should continuously illuminate the MIL The scan tool will command BOTH the PCM and the AF ECM to turn the MIL OFF This steps tests id the MIL Input circuit is requesting MIL illumination There should not be a MIL Input while the MIL is commanded OFF 20
167. ircuit high circuit shorted to ground or shorted to the HO2S low circuit Is the action complete Test the HO2S high and low circuits for continuity between the engine harness circuit splices and the AF ECM connector terminals Measure for continuity between the oxygen sensor connector and the AF ECM connector Test for proper terminal contact at the AF ECM connector terminals and at the 10 way LPG harness to engine harness connector terminals Repair wiring or terminals as necessary Was a wiring or terminal repair made Turn the ignition OFF Remove the jumper from the HO2S low circuit terminal Disconnect the PCM connector that contains the HO2S B2 S1 high signal circuit Using a DVOM measure and record the resistance between the HO2S high signal circuit and ground Using a DVOM measure and record the resistance between the HO2S high signal circuit and the HO2S low circuit Is infinite resistance measured on both tests Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Step Acin Values Go to Step 16 Go to Step 13 The HO2S may be detecting a lean exhaust Perform the AF Fuel System Diagnosis and return to this step Go to Step 16 Go to Step 16 Was a lean AF fuel system condition found and repaired Replace the AF ECM Refer to AF ECM Replacement Is the replacement complete Replace the HO2S Refer to HO2S Replacement in Engine Controls in the GM G Van service manual Is the replace
168. is may help isolate the location of the malfunction Never solder the HO2S wires For proper wire and connector repair refer to Wiring Repairs in Engine Electrical Test Description The number s below refer to the step numbers on the diagnostic table 2 This step determines if proper sensor activity us present When in closed loop fuel control the HO2S voltage should rapidly swing above the bias voltage 2002 LPG G Van Service Manual Supplement Page 114 6 This step determines if the PCM and the high and low circuits between the PCM and HO2S connector are operating properly 9 This step determines if the HO2S heater circuit operates correctly up to the HO2S connector 10 This step determines if the proper circuit resistance exists between the HO2S low circuit and the PCM ground QUANTUM PROPANE FUEL SYSTEM 15 This step determines if the proper circuit resistance exists between the HO2S low circuit and the PCM ground with a cold sensor A loose HO2S or poor cold thread to exhaust electrical contact will cause higher resistance when the HO2S is cold Although 500 ohms is allowed typical resistance should be less than 50 ohms DTC P0134 DTC 42 HO2S Insufficient Activity Bank 1 Sensor 1 Did you perform the Alternative Fuels AF Powertrain On Board Diagnostic OBD System Check Use a scan tool to establish communication with the AF ECM Capture the DTC information from the AF ECM in the scan tool
169. is will be accompanied by lean driveability conditions and a powdery white deposit on the sensor e Faulty HO2S Bank 1 Sensor 1 If the HO2S Bank 1 Sensor 1 is internally shorted the Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM HO2S Bank 1 Sensor 1 voltage displayed will be over 1V Try disconnecting the HO2S Bank 1 Sensor 1 if the displayed voltage goes from over 1000 mV to around 450 mV replace HO2S Bank 1 Sensor 1 e Never solder the HO2S wires Test Description The numbers below refer to the step numbers on the diagnostic table 3 An HO2S contaminated by silicon will have a white powdery deposit on the portion of the HO2S that is exposed to the exhaust stream The usual cause of the silica contamination is the use of unapproved silicon RTV engine gasket material or the use of silicon based sprays or fluids within the engine If the cause of this contamination is not corrected the replacement HO2S will also become contaminated 8 An HO2S contaminated by silicon will have a white powdery deposit on the portion of the HO2S that is exposed to the exhaust stream The usual cause of the silica contamination is the use of unapproved silicon RTV engine gasket material or the use of silicon based sprays or fluids within the engine If the cause of this contamination is not corrected the replacement HO2S will also become contaminated 2002 LPG G Van Service Manual Supplement Page 108 QUANTUM PROPANE FUEL SY
170. ition at ICS An inaccurate MAF sensor Repair any of the above conditions as necessary Was a condition found and repaired Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM i n Vales Yes No Turn the ignition OFF Disconnect the AF ECM connectors Install a ground jumper wire to the underhood LPL at connector C008 Pin B Refer to Engine Control Schematics Runthe engine until normal operating 1 0 volts temperature is reached Using a scan tool monitor the HO2S B1 S1 voltage an voltage fixed greater than the value Go to Step 7 Go to Step 11 Turn the ignition OFF Disconnect the HO2S B1 S1 connector Leave the AF ECM disconnected Jumper the HO2S low circuit terminal engine 351 ur 551 harness side to a known good ground Turn the ignition ON while leaving the engine OFF Using a scan tool monitor the HO2S B1 S1 voltage Is the HO2S voltage within the value range specified Go to Step 8 Go to Step 9 The HO2S may be detecting a rich exhaust condition Inspect for one of the following conditions HO2S connector water intrusion Silicone contaminated HO2S Fuel contaminated engine oil Incorrect fuel pressure Low coolant level cooling system not bled at LPR Leaking low pressure regulator LPR Rich condition at fuel mixer Rich condition at FCS Rich condition at ICS An inaccurate MAF sensor Repair any of the above or similar engine conditions as necessary Was a condition fo
171. itor the HO2S B1 S1 volts voltage Is the voltage fixed within the specified range Go to Step 6 Go to Step 17 Turn the ignition OFF Disconnect the HO2S B1 S1 electrical connector Jumper the HO2S low circuit to a known good ground Jumper the HO2S high signal circuit to a know 20 mV good ground Turn the ignition ON leaving the engine OFF Use the scan tool to monitor the HO2S B1 S1 voltage Is the voltage less than the specified value Go to Step 9 Go to Step 7 Turn the ignition OFF Remove the jumpers from the HO2S terminals Disconnect the PCM connector containing the HO2S high and low circuits Use a DVOM to measure continuity of the HO2S 5 ohms high signal circuit and HO2S low signal circuit between the PCM connector and the HO2S connector terminal engine harness side Are both resistances less than the specified value Goto Step 8 Goto Step 11 1 Inspect for proper PCM connector terminal Go to Step 22 Go to Step 21 contact 2 Repair the terminals as necessary Was a terminal repair made 1 Remove the jumpers from the HO2S terminals 2 Connect a test lamp between the HO2S heater ignition feed and heater ground circuit terminals engine harness side 3 Turn the ignition ON leaving the engine OFF Does the test lamp illuminate Go to Step 10 Go to Step 12 Turn the ignition OFF Reconnect the HO2S connector Disconnect the PCM connector containing the HO2S low circuit and the PCM connector
172. its that the PCM provides Disconnect the AF ECM connector that contains the 5 volt reference circuit to determine if the ECM is the cause of the short Disconnect the other sensors that are connected to the PCM 5 volt reference circuits to determine if a sensor is the cause of the short Repair wiring or replace components as necessary Was a repair made Go to Step 15 Go to Step 13 2002 LPG G Van Service Manual Supplement Page 92 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Value s Replace the TP sensor Refer to TP Sensor Replacement in Engine Controls in the GM G Van service manual Is the replacement complete Go to Step 15 No Important The following PCM replacement procedures must be completed before attempting to operate the vehicle 1 Replace the PCM Referto PCM Replacement in Engine Controls in the GM G Van service manual Program flash the replacement PCM with the correct LPG software and calibration Is the replacement complete Go to Step 15 Replace the AF ECM Refer to AF ECM Replacement Is the replacement complete Go to Step 15 Using the scan tool clear the DTC information from BOTH control modules Operate the vehicle under the Conditions for Running the DTC Using the scan tool parameter DTC STATUS ensure that this DTC runs System OK Go to Step 2 Did this DTC RUN and PASS eis PUTES 2002 LPG G Van Service Manual Supplement Page 93 Website 9 2 0
173. l Connect any dis connected components fuses etc Using a scan tool clear DTC information from the AF ECM and the PCM Turn OFF the ignition and wait 30 seconds Start the engine and operate the vehicle Observe the MIL Observe vehicle performance and driveability After operating the vehicle inspect the AF ECM and the PCM for stored DTCs Go to AF Powertrain i i OBD System ee vehicle operate normally with no stored System OK GE 2002 LPG G Van Service Manual Supplement Page 33 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Wait to Drive Lamp Circuit TRANS P Fuse Fuse Block 10A PNK 1020 Underhood Fuse Relay Center Instrument Panel C2 C100 Malfunction Wait To Indicator Drive 1020 Lamp MIL Lamp 139 C004 PNK To OEM Components BRN WHT PNK 1020 BRNAWHT 419 BLK 450 KA 9005 PPL 914 G103 To E C003 Back of Ignition PNK 1020 Right Relay Cylinder Head DK BLU 919 BRN WHT 419 C002 15 C001 CLR 2 31 22 de BLU C2 RED to Batey igion w Wait To MiL Atematve Alternative Fuel Atematie UU ER 7 Powertrain 1 Power Power Control rive Lamp Control Fuel AF 1 Engine Control l uel ontrol Control i Output Output Input Enable Module Enable Module PCM i Ground Ground Ground Ground AF ECM eebe 21 S E ir AS C001 CLR S006 G103 Back of Right Cylinder Head Circuit Description The Wait to Driv
174. lacement Is the replacement complete Website 9 2 03 a HUANTUMT PROPANE FUEL SYSTEM PROPANE FUEL SYSTEM Sup Action ent Ye NW Using the scan tool clear the DTC information from BOTH control modules Operate the vehicle under the Conditions for Running the DTC Using the scan tool parameter DTC STATUS ensure that this DTC runs Did this DTC RUN and PASS System OK Go to Step 2 2002 LPG G Van Service Manual Supplement Page 89 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM DTC P0122 DTC 22 Throttle Position TP Sensor Circuit Low Voltage Powertrain Control Module PCM Circuit Description The throttle position TP sensor is a potentiometer The PCM supplies about 5 volts on the TP sensor reference voltage circuit The PCM also supplies a ground circuit to the TP sensor When the throttle is pressed the TP signal voltage rises to near the supplied 5 volts As the throttle is released the TP signal voltage drops to around 0 6 volts The PCM and the AF ECM monitor the TP signal circuit voltage and determine the angle or opening of the throttle blade This DTC is used to indicate a TP signal voltage that is below the normal operating range of the sensor This is a type B DTC Website 9 2 03 FM aed Pw ee AN EE NA 7 Powertrain 1 Alternative Fuel i Control i Engine Control 1 ECT Sensor IAT Sensor 5 Volt 5 Volt Module f ECT Sensor IAT Sensor 5 Volt Module GE darla e mom
175. le body for leaks nspect the vacuum hoses in the mixer area for proper connection and condition Inspect the fuel hose connection between the LPR and mixer assembly for damage or leakage Inspect the vacuum hoses to the ETC solenoid Was a problem found and corrected eee Ge ee 2002 LPG G Van Service Manual Supplement Page 38 With the engine idling observe the pressure reading for the LPR secondary pressure 5 Does the fuel pressure fluctuate rhythmically OUTSIDE the specified range Go to Step 29 Go to Step 6 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Agen Valls B Go to Step 12 Go to Step 9 Inspect the air intake stream between the mixer assembly and the throttle body for vacuum leaks Inspect the vacuum hoses from the mixer to the FCS and ICS for proper connection and condition Go to Step 30 Go to Step 10 Was a problem found and repaired o p p Connect a water column gauge or a manometer to the secondary test port of the low pressure regulator LPR Crank the engine and observe the pressure reading for the LPR secondary pressure Does the fuel pressure indicate a vacuum is present Inspect the fuel hose connection between the LPR and the mixer assembly for damage or leakage Go to Step 30 Go to Step 11 Was a problem found and repaired Go to Step 30 Go to Step 28 1 Connect a 0 10 psi gauge to the primary test port of the low pressure regulator LPR 2 Crank the engine and observe the
176. least 30 seconds The engine operating temperature the HO2S will produce a coolant temperature must be greater than 50 C voltage in relation to the oxygen content of the AND the mass air flow above 4 4 gms sec for at exhaust The HO2S requires an operating least 30 seconds for the AF ECM to determine temperature of 600 F 360 C to produce voltage the HO2S is at operating temperature The HO2S will produce more voltage when the e The AF ECM is operating in closed loop fuel exhaust is rich and less voltage when the exhaust is control lean The HO2S operating range is around 0 10 volts 100 mV to 1 volt 1000 mV The PCM Conditions for Setting the DTC supplies a bias or reference voltage to the HO2S This bias voltage is around 450 mV The AF ECM monitors an HO2S signal voltage of an greater than 1 0 volt 1000 mV for 5 seconds This DTC is used to indicate an HO2S signal voltage continuously that is above the normal operating range of the sensor This DTC is a type B DTC 2002 LPG G Van Service Manual Supplement Page 107 Website 9 2 03 Action Taken When the DTC Sets The AF ECM will control fuel trim based upon the Bank 2 Sensor 1 signal If a Bank 2 Sensor 1 DTC sets the AF ECM will operate in open loop fuel control e A first failure of this DTC will NOT illuminate the MIL and will store as Last Test Failed but not as History e The AF ECM will illuminate the MIL and store the DTC as History TWO consecutive drive trips th
177. lighter accessory plug and storage compartment lamp Install the center consol Install the center consol mounting hardware Install the IP lower trim panel to the IP PROPANE FUEL FILTER REPLACEMENT Removal Procedure 1 o0 RON Relieve the propane fuel system pressure Refer to Propane Fuel System Pressure Relief Disconnect the negative battery cable Disconnect the fuel inlet line from the filter Disconnect the fuel outlet line from the filter Remove the nut retaining the filter clamp Remove the propane fuel filter Installation Procedure mk Install the propane fuel filter Install and secure the filter clamp and nut Connect the fuel outlet line to the filter e Tighten the fitting to 37 Nem 27 lb ft Connect the fuel inlet line to the filter e Tighten the fitting to 37 Nem 27 lb ft Start the vehicle and leak check the propane fuel System at each serviced fitting 2002 LPG G Van Service Manual Supplement Page 189 QUANTUM PROPANE FUEL SYSTEM PCV Make up Air Hose T3 E Cyl X imc b Sr mE CAU Tp Fuel Mixer 31 B ae ee Cover Fuel Vapor ICS Hose Fuel Mixer Outlet Elbow Low Pressure Low Pressure Lock off LP Regulator LPR LOW PRESSURE LOCK OFF LPL REPLACEMENT UNDERHOOD Removal Procedure o RON ND 8 9 10 11 12 13 14 15 16 Relieve the propane fuel system pressure Refer to Propan
178. ltage 2 Repair the circuit as necessary Go to Step 20 Go to Step 15 Go to Step 20 Go to Step 18 Go to Step 20 o Go to Step 20 Goto Step 19 Was a circuit repair necessary 1 Check the terminal contact at the PCM connector 2 Repair terminal contact as necessary Was a terminal repair necessary The fault is in the instrument panel Refer to Instrument Cluster System Check in Body and Accessories in the GM G Van service manual Is the diagnosis and repair of the base vehicle system complete 1 Check terminal contact at the AF ECM connector 2 Repair terminal contact as necessary 1 Testthe MIL Control circuit between the AF ECM connector terminal and the IP for an open 2 Repair the circuit as necessary Was a circuit repair necessary Go to Step 20 Go to Step 16 Was a terminal repair necessary 2002 LPG G Van Service Manual Supplement Page 32 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM ion Valet Ye No gt gt Important The following PCM replacement procedures must be completed before attempting to operate the vehicle 1 Replace the PCM Refer to PCM Replacement in Engine Controls in the GM G Van service manual 2 Program flash the replacement PCM with the correct LPG software and calibration Is the replacement complete Go to Step 20 Replace the AF ECM Referto AF ECM Replacement 19 Is the replacement complete Go to Step 20 Remove all test equipment except the scan too
179. ltage less than the specified value Go to Step 10 Goto Step 11 Inspect the signal circuit between the PCM EN Go to Step 12 Goto Step 11 connector and the 10 way AF harness connector Go to Step 12 C005 for the following conditions Open circuit High resistance Poor terminal contact Repair wiring or terminals as necessary Was a wiring repair or terminal repair made Replace the ECT sensor Refer to ECT Sensor Replacement in Engine Controls in the GM G VAN service manual Is the replacement complete Replace the AF ECM Refer to AF ECM Replacement Important The following PCM replacement procedures must be completed before attempting to operate the vehicle 1 Replace the PCM Refer to PCM Replacement in Engine Controls in the GM G VAN service manual Program flash the replacement PCM with the correct LPG software and calibration Is the replacement complete Go to Step 12 Go to Step 12 2002 LPG G Van Service Manual Supplement Page 79 Is the replacement complete Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM se Ado Valet ves Ne Using the scan tool clear the DTC information from BOTH control modules Operate the vehicle under the Conditions for Running the DTC Using the scan tool parameter DTC STATUS ensure that this DTC runs Did this DTC RUN and PASS SE EE 2002 LPG G Van Service Manual Supplement Page 80 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM
180. lter and check for dirt or restriction Check the transmission shift pattern and the downshift operation Fuel System Checks Check for a restricted fuel filter contaminated fuel or improper fuel pressure Refer to AF Fuel System Diagnosis Check for the proper ignition output voltage with the spark tester J 26792 or the equivalent Check for proper installation of the mixer module assembly Check all air inlet ducts for condition and proper installation Check for fuel leaks between the LPR and the mixer Verify that the LPG tank manual shut off valve is fully open Verify that liquid fuel not vapor is being delivered to the LPR Sensor Checks Check the Heated Oxygen Sensor HO2S for contamination and performance Refer to Heated Oxygen Sensor in the GM G Van Service Manual Check for proper operation of the MAP sensor Check for proper operation of the ECT sensor Check EGR system for proper operation Exhaust System Checks Check the exhaust system for a possible restriction Inspect the exhaust system for damaged or collapsed pipes Inspect the muffler for signs of heat distress or for possible internal failure Check for possible plugged catalytic converter Refer to Restricted Exhaust System Diagnosis or Exhaust System in the GM G Van Service Manual Engine Mechanical Check Check the engine for the following e Engine compression e Valve timing e Improper or worn camshaft Refer to Engine Mechanical in the
181. m BOTH control modules Operate the vehicle under the Conditions for Running the DTC Using the scan tool parameter DTC STATUS ensure that this DTC runs Did this DTC RUN and PASS Ge E 2002 LPG G Van Service Manual Supplement Page 57 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM DTC P0106 DTC 32 MAP System Performance Circuit Description The manifold absolute pressure MAP sensor is a pressure sensor The PCM supplies about 5 volts on the MAP sensor reference voltage circuit The PCM also supplies a ground circuit to the MAP sensor When manifold vacuum is low the MAP signal voltage rises to near 4 5 volts As manifold vacuum increases the MAP signal voltage drops to around 1 0 volt The PCM and the AF ECM monitor MAP signal voltage and determine the vacuum within the intake manifold The vehicle also uses the MAP sensor to determine the barometric pressure when the ignition switch is turned ON and the engine is NOT cranked This BARO reading may also be updated whenever the engine is operated at wide open throttle This DTC is used to indicate a MAP sensor signal voltage that does not change when TP sensor voltage changes This DTC is a type A DTC Conditions for Running the DTC e The engine has been operating for greater than 5 seconds Website 9 2 03 Tica wae goad Ganon dn dad aa COLA eid a LL ade T Bowertrain ici gg pete Oe ed Alternative Fuel i Control i Engine Control 1 ECT Sensor I
182. me data Conditions for Clearing the MIL DTC e The Last Test Failed status will clear when the DTC runs and passes e The AF ECM will turn OFF the MIL after THREE consecutive drive trips that the DTC runs and passes e The History status will clear after FORTY consecutive WARM UP cycles with NO failures of ANY DTC e All information can be cleared using a scan tool e Interruption of Control Module AF ECM PCM power and ground MAY clear DTC information Clearing DTC information with this method is inconsistent and should not be performed Diagnostic Aids Fault Not Present Fault Not Present indicates the condition that caused the DTC to set is intermittent and not currently present Refer to Intermittents in Symptom diagnosis for additional information If any additional DTCs were stored proceed to the applicable DTC table in the order stated in the OBD System Check Preliminary Checks Check the following conditions e Low or empty LPG fuel tank For proper LPG fuel system operation liquid fuel is required at the LPR inlet If the fuel level becomes so low that fuel vapor is delivered to the LPR inlet the Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM air fuel mixture will be lean and the MIL may illuminate Also the vehicle will start and idle normally but hesitate and stumble under load If the DTC is current verify that the fuel tank is at least 1 4 full If the DTC is stored in history verify with the oper
183. ment complete Reconnect all disconnected or removed components connectors LPL test jumper fuses etc Using the scan tool clear the DTC information from BOTH control modules Using the scan tool communicate with both control modules to reset the fuel trim values to zero Operate the vehicle under the Conditions for Running the DTC Using the scan tool parameter DTC STATUS ensure that this DTC runs Important The following PCM replacement procedures must be completed before attempting to operate the vehicle 3 Replace the PCM Refer to PCM Replacement in Engine Controls in the GM G Van service manual 4 Program flash the replacement PCM with the correct LPG software and calibration Is the replacement complete Go to Step 16 System OK Go to Step 2 2002 LPG G Van Service Manual Supplement Page 128 Did this DTC RUN and PASS Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM DTC P0152 DTC 65 HO2S Circuit High Voltage Bank 2 Sensor 1 T Q S o Underhood Fuse Relay r HO2S Bank 1 4 Sensor 1 PNK HO2S B251 Signal Ignition Power Ground HO2S Bank 1 Sensor 1 G103 Circuit Description The heated oxygen sensor is used to determine the oxygen content of the engine s exhaust The oxygen content indicates when the engine is operating lean or rich When the engine is operating lean the exhaust will have more oxygen content Once at operating temperature
184. ment in Engine Controls in the GM G Van service manual Go to Step 15 2002 LPG G Van Service Manual Supplement Page 133 Is the replacement complete Important The following PCM replacement procedures must be completed before attempting to operate the vehicle 1 Replace the PCM Refer to PCM Replacement in Engine Controls in the GM G Van service manual 2 Program flash the replacement PCM with the correct LPG software and calibration Replace the AF ECM Refer to AF ECM Replacement Is the replacement complete Go to Step 15 Is the replacement complete Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Sep Mio Lie Yes No Reconnect all disconnected or removed components connectors LPL test jumper fuses etc Using the scan tool clear the DTC information from BOTH control modules Using the scan tool communicate with both control modules to reset the fuel trim values to zero Operate the vehicle under the Conditions for Running the DTC Using the scan tool parameter DTC STATUS ensure that this DTC runs Did this DTC RUN and PASS System OK Go to Step 2 2002 LPG G Van Service Manual Supplement Page 134 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM DTC P0154 DTC 63 HO2S Circuit Insufficient Activity Bank 2 Sensor 1 p Ta wie A ve ge o Kasel Se eh Module PCM Signa Fee Module AF ECM Aer dar yr VOR Y G001 CLR 1667
185. minal to a known good ENGINE ground If the jumper fuse opens repair the signal circuit shorted to battery voltage Other DTCs may be 0 08 volts set i Observe the TP sensor voltage data parameter Is the voltage less than the specified value SE EE Connect a fused jumper between the TP signal circuit terminal and the 5 volt reference circuit terminal Connect another fused jumper between the TP sensor ground circuit terminal and the 5 volt 0 08 volts reference circuit jumper Other DTCs may be set Observe the TP sensor voltage data parameter Does the scan tool display TP sensor voltage less than the specified value Go to Step 11 Go to Step 15 1 Test the TP signal circuit for a short to ground or to the sensor ground circuit 2 Repair wiring as necessary Was a wiring repair made Go to Step 19 Go to Step 18 Test the TP signal circuit for a short to voltage if the jumper fuse opens or a short to the 5 volt reference circuit Inspect the TP sensor connector for poor terminal contact Repair wiring or terminals as necessary Was a wiring or terminal repair made Go to Step 19 Go to Step 16 2002 LPG G Van Service Manual Supplement Page 87 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Sep Agen LL Valet Yes Ne Turn on the ignition OFF Disconnect both AF ECM connectors Turn the ignition ON with the engine OFF Re measure the voltage on the 5 volt reference 4 8 5 2 volts cir
186. minal using a fused jumper 3 Observe the TP sensor data parameter 4 8 volts Does the TP sensor data parameter indicate TP voltage greater than the specified value Go to Step 12 Go to Step 7 Remove the jumper Connect a DVOM between the 5 volt reference circuit terminal and ground 4 8 volts Measure the voltage on the 5 volt reference circuit Is the voltage less than the specified value Go to Step 10 Go to Step 8 Inspect the TP sensor signal circuit for an open or high resistance between the sensor connector and the PCM Repair wiring as necessary Was a wiring repair made Go to Step 15 Go to Step 9 Test the TP sensor signal circuit for a short to engine ground or to the sensor ground circuit Disconnect the AF ECM connector containing the TP sensor signal to determine if the ECM is the cause of the short Repair wiring as necessary Was a wiring repair made Go to Step 15 Go to Step 13 Inspect the 5 volt reference circuit for an open or high resistance condition between the sensor connector and the PCM connector terminal Inspect for proper terminal contact at both the PCM connector and the TP sensor connector Repair wiring or terminal contact as necessary Was a wiring or terminal repair necessary Go to Step 15 Go to Step 11 Inspect all 5 volt reference circuits or a short to ground Some 5 volt reference circuits are shared with the PCM The short may be located on either of the 5 volt reference circu
187. n content indicates when the engine is operating lean or rich When the engine is operating lean the exhaust will have more oxygen content Once at operating temperature the HO2S will produce a voltage in relation to the oxygen content of the exhaust The HO2S requires an operating temperature of 600 F 360 C to produce voltage The HO2S will produce more voltage when the exhaust is rich and less voltage when the exhaust is lean The HO2S operating range is around 0 10 volts 100 mV to 1 volt 1000 mV The PCM supplies a bias or reference voltage to the HO2S This bias voltage is around 450 mV The AF ECM monitors the bias voltage as well as the voltage produced by the HO2S During normal closed loop fuel control the AF ECM will add fuel richen the mixture when the HO2S indicates a lean exhaust content When the HO2S indicates a rich exhaust content the AF ECM will add fuel lean the mixture This oscillation above and below the bias voltage sometimes referred to Website 9 2 03 TAN WHT TAN WHT 1653 C004 Heated Oxygen Sensor HO2S Bank 1 Sensor 1 as activity or switching can be monitored with the HO2S signal voltage The oxygen sensor contains a heater The heater is used to quickly warm the sensor to operating temperature The heater will also maintain operating sensor temperature during extended idle conditions A functions oxygen sensor heater will allow the sensor to produce voltage in less time A sensor a
188. n short to ground or short to power Refer to Engine Controls Schematics Was a problem found Disconnect the LPL electrical connector Measure the resistance of the LPL Was the resistance within specification Disconnect the FCS electrical connector Measure the resistance of the FCS Was the resistance within specification Disconnect the ICS electrical connector Measure the resistance of the ICS Was the resistance within specification Check AF ECM connectors C001 and C002 for damaged pins or bad connections Was a problem found Replace the component Is the action complete Repair the circuit as necessary Is the action complete Replace the AF ECM Refer to AF ECM Replacement Is the action complete Clear the DTC Operate the vehicle within the conditions for setting this DTC as specified in the supporting text Check to see if the MIL still illuminates Did the diagnostic run and pass Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Yves No Go to Step 16 Go to Step 12 Go to Step 16 Go to Step 13 Go to Step 16 Go to Step 17 Go to Step 14 Go to Step 15 Go to Step 14 Goto Step 15 Go to Step 14 Goto Step 15 Go to Step 16 Go to Step 17 Go to Step 18 Pw Go to Step 18 ES Go to Step 18 System OK Go to Step 2 2002 LPG G Van Service Manual Supplement Page 166 Value s 120 160 170 240 170 240 QUANTUM PROPANE FUEL SYSTEM Symptom Diagnosis
189. n MAP signal circuit between the MAP signal circuit splice and the AF ECM Is the repair complete Inspect the MAP signal circuit for a short to B Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Sep Ben Vals Go to Step 17 Go to Step 16 1 Inspect for proper terminal contact at the AF ECM Go to Step 17 connector 2 Repair terminal contact as necessary Was a terminal repair made Replace the MAP sensor Refer to MAP Sensor Replacement in Engine Controls in the GM G Van service manual Is the replacement complete Replace the AF ECM Refer to AF ECM Replacement Go to Step 17 System OK Go to Step 2 Is the replacement complete Using the scan tool clear the DTC information from BOTH control modules Operate the vehicle under the Conditions for Running the DTC Using the scan tool parameter DTC STATUS ensure that this DTC runs Did this DTC RUN and PASS Important The following PCM replacement procedures must be completed before attempting to operate the vehicle 1 Replace the PCM Refer to PCM Replacement in Engine Controls in the GM G Van service manual Program flash the replacement PCM with the correct LPG software and calibration Is the replacement complete Go to Step 17 2002 LPG G Van Service Manual Supplement Page 68 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM DTC P0112 DTC 23 IAT Sensor Circuit Low Voltage Powertrain Control Module PCM Circuit
190. n OBD System Check without Scan Tool so A Lee Ye W Important Check for applicable service bulletins before proceeding with this test Do not clear DTCs unless instructed by this diagnostic Go to Turn ON the ignition with the engine OFF Malfunction Geis Sebo Indicator Lamp Does the MIL illuminate A SEN Turn the ignition switch OFF and wait ten seconds Is the action complete Go to Step 3 Turn the ignition switch from OFF to RUN 3 times within 10 seconds leaving the key in the RUN Go to Rosier Malfunction Gata BIS Indicator Lamp o to ircui Does the Wait to Drive light begin to flash DTCs 5 Circuit Important All DTCs are two digits All DTCs will be flashed 3 times before proceeding to the next DTC DTC 12 will always be present and indicates the ECM is in diagnostic retrieval mode All codes have been displayed when DTC 12 is flashed again If DTC P0601 DTC 58 is stored along with multiple DTCs refer to Diagnostic Aids before going to the applicable DTC table Observe and record any DTCs Were any DTCs other than DTC 12 stored in the AF ECM Go to Step 5 Go to Step 6 2002 LPG G Van Service Manual Supplement Page 28 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Before going to the applicable DTC table while in AF ECM DTC retrieval mode turn ignition from OFF to ON 3 additional times and wait 10 seconds after the MIL turns off before turning ignition off This will clear all AF ECM
191. n on the Vehicle Emission Control Label Check the owner s driving habits for the following items Is the A C ON full time Defroster mode ON Is there excessive idling or stop and go driving Are the tires at the correct air pressure Are excessively heavy loads being carried Is their often rapid acceleration Suggest to the owner to fill the fuel tank and to recheck the fuel economy Suggest to the driver to refer to Important Facts on Fuel Economy in the GM G Van Owner s Manual Check the Engine Coolant Temperature ECT sensor with the scan tool Compare the engine coolant temperature with the ambient air temperature on a cold engine If the coolant temperature reading is more than 5 degrees greater or less than the ambient air temperature on a cold engine check for high resistance in the coolant sensor circuit Refer to DTC P0118 ECT Sensor Circuit High Voltage or DTC P1115 ECT Sensor CKT Intermittent High Voltage in the GM G Van Service Manual Check the Mass Air Flow MAF sensor Verify that the spark plugs are correct Check the spark plugs Remove the plugs and inspect them for the following conditions Wet plugs Cracks Wear Improper gap Burned electrodes Heavy deposits Check the ignition wires for the following items Cracking Hardness Proper connections Check the coolant level If coolant is added bleed the cooling system using the Schrader valve on the LPR Check the engine thermostat for always
192. n power source Backprobe the ICS connector pin B DK GRN 80 Connect the negative lead of the DVOM to terminal B Is the ICS duty cycle ABOVE the specified range Go to Step 15 Go to Step 13 Disconnect the ECM connector C001 Check the ICS ground circuit between the ICS connector terminal B and C001 for an open or short to ignition power or ground Goto Step 26 Go to Step 14 Goto Step 16 Go to Step 20 Go to Step 26 Go to Step 18 a 2002 LPG G Van Service Manual Supplement Page 45 Was a problem found and repaired Disconnect ECM connector C001 Turn the ignition ON leaving the engine OFF Check ECM cavity C001 pin 12 for a short to power Was a problem found The ICS ignition circuit is open or shorted to ground Check the ICS ignition circuit in the ICS connector terminal A for ignition power Was a problem repaired Replace the AF ECM Refer to AF ECM Replacement Is the replacement complete Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Sep Agen LL Weed Ves Ne Check the vacuum hoses between the mixer LPR FCS and the ICS for kinks obstructions or leakage Go to Step 26 Go to Step 21 Was a problem found and repaired Repair the open or damaged circuit Is the action complete Go to Step 26 Replace the Idle Control Solenoid ICS Refer to dle Control Solenoid Replacement Is the action complete Replace the fuel control solenoid FCS Refer to Fuel Control Sol
193. nated 8 An HO2S contaminated by silicon will have a white powdery deposit on the portion of the HO2S that is exposed to the exhaust stream The usual cause of the silica contamination is the use of unapproved silicon RTV engine gasket material or the use of silicon based sprays or fluids within the engine If the cause of this contamination is not corrected the replacement HO2S will also become contaminated 2002 LPG G Van Service Manual Supplement Page 130 QUANTUM PROPANE FUEL SYSTEM DTC P0152 DTC 65 HO2S Circuit High Voltage Bank 2 Sensor 1 Sep Aeon eet Yes Ne Did you perform the Alternative Fuels AF Powertrain On Board Diagnostic OBD System Check Go to AF Powertrain OBD System Go to Step 2 Check Run the engine until normal operating temperature is reached Using a scan tool establish communication with the AF ECM 1 0 volts Using a scan tool monitor the AF ECM HO2S B2 S1 voltage Is the HO2S voltage fixed greater than the value ecified SH Go to Step 5 Go to Step 3 Go to Step 15 Go to Step 4 The fault is not present Refer to Diagnostic Aids Are there any DTCs stored that have not been diagnosed The condition that set this DTC is not present This DTC may have been set by one of the following conditions A signal wire intermittently shorted to voltage A silicon contaminated HO2S An intermittent rich condition such as the following Incorrect fuel pressure Low c
194. ne View the captured freeze frame data that was stored in Step 2 Observe the data parameters that give an indication of how the vehicle was being operated when this DTC set Operate the vehicle within the conditions for running the DTC and the parameters observed when the DTC set Observe the short term fuel trim values Do the fuel trim values indicate a rich mixture condition is present or does a fuel trim DTC set Go to Step 10 Go to Step 13 Repair the possible causes of rich engine operation Refer to the items in Step 4 Go to Step 14 Go to Step 14 A Go to Step 14 EN Is the repair Important Before replacing a contaminated HO2S determine and repair the cause of the contamination Replace the HO2S Refer to HO2S Replacement in Engine Controls in the GM G Van service manual Is the replacement complete Replace the fuel mixer Refer to Fuel Mixer Replacement Remove and visually inspect the oxygen sensor for silicon contamination Is the oxygen sensor contaminated Goto Step 12 Go to Step 11 Is the replacement complete 2002 LPG G Van Service Manual Supplement Page 153 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Sep Rio Lie Yes No Reconnect all disconnected or removed components connectors fuses etc Using the scan tool clear the DTC information from BOTH control modules Using the scan tool communicate with both control modules to reset the fuel trim values to zero
195. nector Install the LPL to bracket mounting bolts e Tighten the bolts to 12 Nem 9 lb ft Connect the fuel line to the LPL e Tighten the fitting to 37 Nem 27 lb ft Connect the negative battery cable Start the vehicle and leak check the propane fuel System at each serviced fitting Install the engine cover and connect the retaining straps Connect the electrical connectors for the lighter accessory plug and storage compartment lamp Install the center consol Install the center consol mounting hardware Install the IP lower trim panel to the IP 2002 LPG G Van Service Manual Supplement Page 190 QUANTUM PROPANE FUEL SYSTEM LOW PRESSURE REGULATOR LPR REPLACEMENT Removal Procedure Relieve the propane fuel system pressure Refer to Propane Fuel System Pressure Relief Disconnect the negative battery cable Remove the IP lower trim panel from the IP Remove the center console mounting hardware Disconnect the electrical connectors for the lighter accessory plug and storage compartment lamp Remove the center consol 7 Release the engine cover retaining straps and remove the cover 8 Disconnect the fuel line from the LPL 9 Remove the LPL to bracket mounting bolts 10 Disconnect the LPL electrical connector 11 Disconnect the ICS fuel line from the LPR 12 Disconnect the FCS vacuum line from the LPR 13 Remove the LPR to bracket mounting bolts 14 Remove t
196. nifold An intermittent ground in the wire between the connector and the sensor A poor ECM to the engine block ground If the above check out okay the problem may be a faulty heated sensor e All information can be cleared using a scan tool e Interruption of Control Module AF ECM PCM gt power and ground MAY clear DTC information gt Clearing DTC information with this method is inconsistent and should not be performed Never solder the HO2S wires For proper wire and connector repair refer to Wiring Repairs in Engine Electrical in the appropriate GM G Van Service Manual DTC P0131 DTC 44 HO2S Circuit Low Voltage ee t Sensor 1 Stp Action J Values Go to AF Powertrain OBD System Check Was the Alternative Fuels AF Powertrain On Board Diagnostic OBD System Check performed Run the engine until normal operating temperature is reached Using a scan tool establish communication with the AF ECM Using a scan tool monitor the AF ECM HO2S B1 S1 voltage Is the HO2S voltage fixed less than the value specified Go to Step 5 Go to Step 3 2002 LPG G Van Service Manual Supplement Page 103 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Values Yes No The condition that set this DTC is not present This DTC may have been set by one of the following conditions A signal wire intermittently shorted to engine ground or to the HO2S low circuit An open between the engine harness circuit s
197. nition OFF Disconnect the AF ECM connector that contains the IAT sensor signal circuit With the IAT sensor connector disconnected test the IAT signal circuit of continuity Is IAT signal circuit continuity indicated Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Sep Ben Loisi Yes Ne 1 Inspect for proper terminal contact at the AF ECM Go to Step 17 Go to Step 16 Go to Step 17 connector 2 Repair the terminal contact as necessary Was a terminal repair made Repair the open IAT sensor signal circuit between the IAT sensor signal circuit splice and the AF ECM Is the circuit repair complete Replace the AF ECM Refer to AF ECM Replacement Go to Step 17 System OK Go to Step 2 Is the replacement complete Using the scan tool clear the DTC information from BOTH control modules Operate the vehicle under the Conditions for Running the DTC Using the scan tool parameter DTC STATUS ensure that this DTC runs Did this DTC RUN and PASS Important The following PCM replacement procedures must be completed before attempting to operate the vehicle 1 Replace the PCM Refer to PCM Replacement in Engine Controls in the GM G VAN service manual Program flash the replacement PCM with the correct LPG software and calibration Is the replacement complete Go to Step 17 2002 LPG G Van Service Manual Supplement Page 76 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM DTC P0117 DTC 15 En
198. nose the PCM DTCs first Important If DTC P0601 DTC 58 is stored along with different multiple DTCs refer to Diagnostic Aids before going to the applicable DTC table 3 Diagnose DTCs Go to the Have all stored DTCs been diagnosed Go to Step 12 aM Replace the AF ECM Refer to AF ECM Replacement Is the replacement complete P P Go to Step 12 Remove all test equipment except the scan tool Using a scan tool clear DTC information from the PCM and the AF ECM Turn the ignition OFF and wait 30 seconds Start the engine and operate the vehicle Ifa DTC was set ensure that the operation of the vehicle allows the DTC to test Refer to 2 Conditions for running the DTC Observe the MIL Observe vehicle performance and driveability 7 After operating the vehicle inspect the PCM and the AF ECM for stored DTCs Does the vehicle operate with normal performance and driveability with no stored DTCs System OK Go to Step 1 2002 LPG G Van Service Manual Supplement Page 27 10 Go to Is there a driveability symptom Symptoms Go to Step 12 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Test Description without Scan Tool The numbers below refer to the step numbers on the diagnostic table 1 This step verifies operation of the MIL 3 This step enables the AF ECM to display any stored codes 5 This step will clear all AF ECM DTCs and reset fuel trim block learn to its initial value Alternative Fuel AF Powertrai
199. nt CAUTION The propane fuel tank contains liquid and vaporous propane at pressures up to 312 psi Failure to drain the tank before service may cause fire and or personal injury 2 Drain the propane fuel tank Refer to Propane Fuel Tank Draining 3 Remove the fuel sending unit from the tank Installation Procedure Important e Do not use Teflon tape on any fuel fitting Use liquid pipe thread sealant 1 Apply liquid pipe thread sealant to the fittings of the fuel sending unit 2 Install the fuel sending unit in the tank e Tighten to 1 3 TFFT 3 Install the propane fuel tank Refer to Propane Fuel Tank Replacement PRESSURE RELIEF DEVICE PRD TANK REPLACEMENT Removal Procedure 1 Relieve the propane fuel system pressure Refer to Propane Fuel System Pressure Relief 2 Disconnect the negative battery cable 3 Remove the fuel tank cover bolts and the cover CAUTION The propane fuel tank contains liquid and vaporous propane at pressures up to 312 psi Failure to drain the tank before service may cause fire and or personal injury 4 Drain the propane fuel tank Refer to Propane Fuel Tank Draining 5 Disconnect the following electrical connectors e Fuel sending unit FSU e Fuel tank lock off 6 Remove the PRD from the tank 2002 LPG G Van Service Manual Supplement Page 187 QUANTUM PROPANE FUEL SYSTEM Installation Procedure Important 4 5 6 7 Do not use Teflon tape on a
200. ntrol solenoid FCS The FCS converts this to a mechanical signal and modulates air valve vacuum on top of the LPR secondary diaphragm By controlling the pressure on top of the LPR secondary diaphragm the ECM can control the LPR output pressure and fuel flow to the mixer A high FCS duty cycle means the ECM is issuing a lean command to control a rich condition A low FCS duty cycle means the ECM is issuing a rich command to control a lean condition IDLE CONTROL SOLENOID ICS An electrically actuated control solenoid used to meter supplemental fuel to the engine which increases fuel control authority during idle and low speed operation During closed loop operation the ECM commands a duty cycle to the idle control solenoid ICS that is the opposite of the FCS A high ICS duty cycle means the ECM is issuing a rich command to control a lean condition A low ICS duty cycle means the ECM is issuing a lean command to control a rich condition 2002 LPG G Van Service Manual Supplement Page 6 SYSTEM OPERATION FEATURES COLD WEATHER STARTS The AF ECM will illuminate the WAIT TO DRIVE lamp located on the dash until the engine coolant temperature is between OC to 30 C depending on ambient temperature This permits proper LPG vaporization and prevents the low pressure regulator LPR from freezing The AF ECM will shut off the engine by closing the LPL if the operator attempts to drive the vehicle before the coolant has reached t
201. ny fuel fitting Use liquid pipe thread sealant Apply liquid pipe thread sealant to the PRD threads Install the PRD to the tank e Tighten the PRD to 2 3 TFFT Connect the following electrical connectors e Fuel tank lock off e Fuel sending unit FSU Fill the propane fuel tank Leak check the propane fuel system at the PRD Install the fuel tank cover the mounting bolts e Tighten the bolts to 22 Nem 16 lb ft Connect the negative battery cable LIQUID LEVEL GAUGE TANK REPLACEMENT Removal Procedure 1 2 3 Relieve the propane fuel system pressure Refer to Propane Fuel System Pressure Relief Disconnect the negative battery cable Remove the fuel tank cover bolts and the cover CAUTION The propane fuel tank contains liquid and vaporous propane at pressures up to 312 psi Failure to drain the tank before service may cause fire and or personal injury 4 5 6 7 Drain the propane fuel tank Refer to Propane Fuel Tank Draining Disconnect the following electrical connectors e Fuel sending unit e Fuel tank lock off Disconnect the fuel line from the liquid level gauge Remove the liquid level gauge from the tank Installation Procedure Important Do not use Teflon tape on any fuel fitting Use liquid pipe thread sealant Apply liquid pipe thread sealant to the liquid level gauge threads Install the liquid level gauge to the tank e Tighten the liquid level gauge to 2 3 TFF
202. o Replace LPG fuel filter or every 12 months whichever occurs first 3 o Check all vacuum lines and fittings o Check all fuel lines and fittings o Perform ignition system inspection 28 120 000 MILES 200 000 KM o Check intake system for vacuum leaks o Check converter check regulator primary and secondary pressures 61 o Replace LPG fuel filter or every 12 months whichever occurs first 3 o Check all vacuum lines and fittings Check all fuel lines and fittings o Replace spark plugs and perform ignition System inspection 28 o Perform mixer air valve service 60 o FOOTNOTES e 3 An Emission Control Service e 28 Remove and inspect the spark plugs for wear or damage Inspect the spark plug wires for damage Check the spark plug wire connections at the plug and at the distributor Inspect wire harness connections at the distributor Repair or replace parts as necessary 2002 LPG G Van Service Manual Supplement Page 7 60 Remove the mixer cover and spring from the mixer Remove the air valve assembly from the mixer body Inspect for dirt oil contamination or damage Clean or repair as necessary 61 If primary and secondary pressures are within specification no further action is necessary If pressures are out of specification remove converter cover spring and diaphragm Inspect for dirt oil contamination or damage Clean or repair as necessary Website 9 2 03 QUANTUM PR
203. oes the test lamp illuminate Go to Step 11 Go to Step 12 Turn the ignition OFF Remove the jumpers from the HO2S terminals Disconnect the PCM connector containing the HO2S high and low circuits Using a DVOM measure the continuity of the HO2S high signal circuit and the HO2S low signal circuit between the PCM and the HO2S connector terminal engine harness side Are both resistances less than the specified value Go to Step 16 Go to Step 13 Replace the HO2S sensor Refer to Heated Oxygen Sensor HO2S Replacement in the GM G Van service manual Is the action complete pole Step TE Repair the open HO2S heater ground circuit Is the action complete Go to Step 18 1 Repair the lack of power on the HO2S heater ignition feed circuit Ifthe fuse is open repair the short to ground on the circuit An open fuse or lack of power to the fuse may cause other DTCs or symptoms to be present Is the action complete Go to Step 18 Repair the circuit that measured high resistance Is the action complete Go to Step 18 2002 LPG G Van Service Manual Supplement Page 144 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM ae Aon Values Wes No Go to Step 18 Go to Step 15 Inspect the HO2S sensor signal and low circuit for continuity between the AF ECM connector Is the replacement complete ei Go to Step 18 ER 1 Inspect for proper PCM terminal contact 2 Repair the terminals as necessary Was a problem found and rep
204. of ANY DTC All DTC information can be cleared using a scan tool Interruption of Control Module AF ECM PCM power and ground MAY clear DTC information Clearing DTC information with this method is inconsistent and should not be performed Diagnostic Aids Fault Not Present Fault not Present indicates the condition that caused the DTC to set is intermittent and not currently present Refer to Intermittents in Symptom diagnosis for additional information If any additional DTCs were stored proceed to the applicable DTC table in the order stated in the AF OBD System Check Test Description The numbers below refer to the step numbers on the diagnostic table 2 This step determines if the failure condition affects the PCM 3 This step determines if the failure condition is present 4 This step determines if the TP signal is going high only when the throttle is opened 6 This step determines if the TP sensor is the cause of the shorted condition 7 This step determines if an open sensor ground condition is present 8 This step determines if the 5 volt reference circuit is shorted to voltage The 5 2 volts is the maximum output that the PCM should supply on the 5 volt reference circuit DTC P0123 TP Sensor Circuit High Voltage Did you perform the Alternative Fuels AF Powertrain On Board Diagnostic OBD System Check 1 Turn the ignition ON with the engine OFF 2 Using the scan tool establish communication
205. ol Module C2 RED 8 Vehicle Speed Powertrain I Signal VSS Control 1 Control Module PCM I Conditions for Running the DTC e No AF ECM MAF sensor DTCs P0102 36 or P0103 37 are set during this ignition cycle e The MAP sensor signal indicates 105 23 kPa 31 07 Hg or less e MAF is more than 3 gms sec for 1 second continuously e The engine is cranking or running 2002 LPG G Van Service Manual Supplement Page 155 QUANTUM PROPANE FUEL SYSTEM Conditions of Setting the DTC The AF ECM monitors no CKP reference signal for more than 0 5 seconds NOTE The AF ECM may run and set this DTC before the PCM Action Taken When the DTC Sets e The AF ECM will illuminate the MIL and store the DTC as History during ONE drive trip that the diagnostic runs and fails e The AF ECM will record operating conditions at the time the DTC sets This information will be stored as Freeze Frame data Conditions for Clearing the MIL DTC e The Last Test Failed status will clear when the DTC runs and passes e The AF ECM will turn OFF the MIL after THREE consecutive drive trips that the DTC runs and passes e The History status will clear after FORTY consecutive WARM UP cycles with NO failures of ANY DTC e All information can be cleared using a scan tool e Interruption of Control Module AF ECM PCM power and ground MAY clear DTC information Clearing DTC information with this method is inconsis
206. om the LPR secondary chamber into the mixer The system will also automatically sense and compensate for changes in altitude LPG FUEL TANK The LPG fuel tank is located under the rear of the vehicle behind the rear axle LPG fuel fill capacity is 29 gallons The tank complies with ASME and NFPA standards FUEL TANK LOCK OFF The electric fuel tank lock off solenoid provides electronic fuel shut off for pressures up to 312 psi It is a normally closed solenoid operated lock off with a manual shut off override valve If the lock off fails it is designed to fail in the closed position The solenoid has a high temperature coil and is both UL and CGA approved 2002 LPG G Van Service Manual Supplement Page 5 UNDERHOOD LOW PRESSURE LOCK OFF LPL The underhood electric low pressure lock off solenoid provides electronic fuel shut off for pressures up to 312 psi It is a normally closed solenoid operated lock off with a 1 4 diameter fuel orifice If the lock off fails it is designed to fail in the closed position The solenoid has a high temperature coil and is both UL and CGA approved LOW PRESSURE REGULATOR LPR The QUANTUM Model E low pressure regulator LPR is a combined pressure regulator and vaporizer The regulator is a negative pressure two stage configuration that is closed when the engine is not running When the engine is cranking or running the air valve vacuum created is communicated to the regulator T
207. onitors an HO2S signal voltage of less than 0 08 volts 78 mV for 15 seconds continuously Action Taken When the DTC Sets The AF ECM will control fuel trim based upon the Bank 1 Sensor 1 signal If a Bank 1 Sensor 1 DTC sets the AF ECM will operate in open loop fuel control 2002 LPG G Van Service Manual Supplement Page 124 e A first failure of this DTC will NOT illuminate the MIL and will store as Last Test Failed but not as History e The AF ECM will illuminate the MIL and store the DTC as History TWO consecutive drive trips that the diagnostic runs and fails e The AF ECM will record operating conditions at the time the DTC sets This information will be stored as Freeze Frame data Conditions for Clearing the MIL DTC e The Last Test Failed status will clear when the DTC runs and passes e The AF ECM will turn OFF the MIL after THREE consecutive drive trips that the DTC runs and passes e The History status will clear after FORTY consecutive WARM UP cycles with NO failures of ANY DTC e All information can be cleared using a scan tool e Interruption of Control Module AF ECM PCM power and ground MAY clear DTC information Clearing DTC information with this method is inconsistent and should not be performed Diagnostic Aids Check for the following condition e Low or empty LPG fuel tank For proper LPG fuel system operation liquid fuel is required at the LPR inlet If the fuel level becomes so low QU
208. ontrol RED 2531 RED 2531 Engine Speed Alternative Fuels TACH Signal Operation AFO Output Signal Circuit Description The vehicle speed sensor VSS is a magnetic induction sensor The VSS is mounted close to the output shaft gear in the transmission The gear teeth induce an alternating current in the sensor as the output shaft rotates This frequency is applied to the control module at the rate of 40 cycles per output shaft revolution The control module calculates the vehicle speed using this AC voltage signal It the VSS signal is not detected at any vehicle speed for 5 seconds this diagnostic trouble code will set This is a type B DTC Conditions for Running the DTC e No active MAP MAF or CKP sensor DTCs Website 9 2 03 Alternative Fuel Engine Control Vehicle Speed Module AF ECM Signal VSS 15 C002 BLU DK GRN WHT To IP Cluster and Cruise Control Module C2 RED 8 Vehicle Speed Powertrain I Signal VSS Control 1 Control Module PCM I e The MAF is greater than 100 g s e The engine speed is greater than 2500 RPM Conditions for Setting the DTC The AF ECM detects a vehicle speed less than 2 mph MPH for 7 seconds or more Action Taken When the DTC Sets A first failure of this DTC will illuminate the MIL e The AF ECM will record operating conditions at the time the DTC sets This information will be stored as Freeze Frame data 2002 LPG G Van Se
209. oolant level cooling system not bled at LPR Leaking low pressure regulator LPR Rich condition at fuel mixer Rich condition at FCS Rich condition at ICS An inaccurate MAF sensor Repair any of the above conditions as necessary Was a condition found and repaired Go to Go to AF DTC List Intermittents Run the engine until normal operating temperature is reached Using the scan tool establish communication with the PCM 1 0 volts Using a scan tool monitor the HO2S B2 S1 voltage Is the HO2S voltage fixed greater than the value ified specie Go to Step 6 Goto Step 12 Website 9 2 03 2002 LPG G Van Service Manual Supplement Page 131 QUANTUM PROPANE FUEL SYSTEM on Vales Yes No Turn the ignition OFF Disconnect the AF ECM connectors Install a ground jumper wire to the underhood LPL at connector C008 Pin B Refer to Engine Control Schematics Runthe engine until normal operating 1 0 volts temperature is reached Using a scan tool monitor the HO2S B2 S1 voltage bsp voltage fixed greater than the value Go to Step 7 Go to Step 11 Turn the ignition OFF Disconnect the HO2S B2 S1 connector Leave the AF ECM disconnected Jumper the HO2S low circuit terminal engine 351 ur 551 harness side to a known good ground Turn the ignition ON while leaving the engine OFF Using a scan tool monitor the HO2S B2 S1 voltage Is the HO2S voltage within the value range specified Go to
210. ow 10302 Eed punog eubis jeubisg punog jeubis punols punog 4osues deu Josues Josues dl dosuas dg Josues JOSU9S dl Josues Josueg p p 2 q i sai lk i i eh hl hm Aer Eer A ees ei me Em MV ag es E Ween Eso 2e aaa zo rer ma ys ax zo Aez me oo aaa Ms cer INYO 11 wig ir Ma MG LO Lo Zo di INYO cer NHO 11 Aw mana S000 N A 69v W1g NHO 3 d 9 Lup ma MO 910S 69v 2642 Mia 0972 18 LZOS eee 69v 119 NJO Cer SE Ly fr1853 N9 11 zer NYO 11 g g V 2 g josues Josueg dv d1 pere pug uonisod uw Damen SE SE 9 v v04c ANO PO V 2c0S AYO Zt NYL cv 8L0S NYL OLY 13A q a8 V o ioa MS E rozz AY 1022 AYO cLV NYL CLV NV L vOLe AJO Oly TSA 18 zooo ez gio ZL nig Lo gp cem g 438 zo e WOJ dv eouoJ9joy Jeubis jeubis i mod ecualajoy eouel9joy jeu amp is 9e npolN JOAS Josueg Li Josues 103 1 SIMNPON 1 yoAc HOA S Josuas Lei ojuoy euiBu3 l Jo3u02 JON 9Angeuloejv EQ og aR Ae sab PMNS T TEE i UIgJJ9MOd i A EA m m m meme cen sie e ps dettes SEM ea punog JOSU9S ma 08 LO L922 41a Josuag 193 esnejadue is euibu3 Ol 13A ZL0S Ol TSA 18 LO v usis Josues 193 2002 LPG G Van Service Manual Supplement Page 12 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Mass Airflow MAF Sensor c r n18 z009 W03 ay empow 0 yuoy euiBu3 9n4 e neuiejyv euBis JOSU8S Josues 3VIN MOL
211. parameter Does the IAT sensor data parameter indicate IAT voltage less that the specified value Go to Step 10 Go to Step 11 Inspect the signal circuit between the PCM and Go to Step 12 Go to Step 11 10 way AF connector C005 for the following Go to Step 12 conditions e Open circuit e High resistance e Poor terminal contact Repair the wiring or terminals as necessary Was a wiring repair or terminal repair made Replace the IAT sensor Refer to AT Sensor Replacement in Engine Controls in the GM Van service manual Is the replacement complete Replace the AF ECM Refer to AF ECM Replacement Important The following PCM replacement procedures must be completed before attempting to operate the vehicle 3 Replace the PCM Refer to PCM Replacement in Engine Controls in the GM G VAN service manual Program flash the replacement PCM with the correct LPG software and calibration Go to Step 12 Is the replacement complete Go to Step 12 2002 LPG G Van Service Manual Supplement Page 71 Is the replacement complete Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM step ton w ves no Using the scan tool clear the DTC information from BOTH control modules Operate the vehicle under the Conditions for Running the DTC Using the scan tool parameter DTC STATUS ensure that this DTC runs Did this DTC RUN and PASS System OK Go to Step 2 2002 LPG G Van Service Manual Supplement Page 72
212. plement Page 143 The fault is not present Refer to Diagnostic Aids Are any DTCs stored that have not been diagnosed Turn the ignition OFF Disconnect the HO2S B2 S1 connector Connect an un powered test lamp between the HO2S heater ignition feed and ground circuit terminals engine harness side Turn the ignition ON leaving the engine OFF Does the test lamp illuminate The condition that set this DTC is not present This DTC may have been set by one of the following conditions An intermittently open or high resistance HO2S high signal circuit or low circuit An intermittently open or high resistance HO2S heater feed or ground circuit A faulty HO2S or gasoline PCM terminal contact A defective HO2S Repair any of the above conditions as necessary Was a condition found and repaired Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Step Action Vale Yes mo Disconnect the test lamp Jumper the HO2S low circuit terminal to a known good ground Jumper the HO2S high circuit terminal to a known good ground Use the scan tool to monitor the HO2S B2 S1 20 mV voltage Ensure the ignition is ON while the engine is OFF ifi Is the voltage less than the specified range Go to Step 10 Go to Step 9 Connect the test lamp between the HO2S heater ignition feed circuit terminal engine harness side and a known good ground Ensure the ignition is ON while the engine is OFF D
213. plice and the AF ECM connectors HO2S connector water intrusion An exhaust leak between the HO2S and the engine An intermittent lean condition such as the following Vacuum leaks Restricted fuel filter Low fuel pressure Lean condition at LPR Lean condition at fuel mixer Lean condition at FCS Lean condition at ICS An inaccurate MAF sensor Repair any of the above conditions as necessary Was a condition found and repaired Go to Step 16 Go to Step 4 The fault is not present Refer to Diagnostic Aids Are there any DTCs stored that have not been diagnosed Gore Sots AF DTC List Intermittents Run the engine until normal operating temperature is reached Using the scan tool establish communication with the PCM Using a scan tool monitor the HO2S B1 S1 voltage Is the HO2S voltage fixed less that the value specified Go to Step 6 Goto Step 11 Turn the ignition OFF Disconnect the AF ECM connectors Install a ground jumper wire to the underhood LPL at connector C008 Pin B Refer to Engine 78 mV Control Schematics Run the engine until normal operating temperature is reached Using a scan tool monitor the HO2S B1 S1 voltage Is the HO2S voltage fixed less than the value specified Go to Step 7 Go to Step 12 2002 LPG G Van Service Manual Supplement Page 104 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Stepe Action Values Yes No Turn the ignition OFF Disconnect the HO2S
214. pplied with ignition voltage and a ground The MAF sensor heats a wire grid within the sensor to a predetermined temperature As inlet air flow across and cools the wire grid the MAF sensor must increase current flow to the wire grid to maintain a constant temperature The MAF sensor converts the required wire grid current flow into a frequency signal The PCM and the AF ECM monitor the MAF signal circuit frequency and determine the flow and mass of the air entering the engine The PCM and the AF ECM convert the MAF signal circuit frequency into a grams per second value During low air flow rates such as at engine idle the MAF sensor will produce a low frequency signal around 2 000 Hz or 6 grams per second During high air flow rates such as wide open throttle with load the MAF sensor will produce a high frequency signal around 9000 Hz or 125 grams per second Website 9 2 03 Sensor Signal Module PCM Signal i Powertrain Alternative Fuel Control Sensor Engine Control Module AF ECM C002 BLU MAF S Signal Mass Air Flow MAF Sensor This DTC is used to indicate a MAF sensor frequency that is below the normal operating range of the sensor This DTC is a type A DTC Conditions for Running the DTC Cranking Test e The engine is cranking but has not yet started e The battery voltage is greater than 8 volts Running Test e Engine run time is greater than 10 seconds e Battery voltage is greater than
215. present and can be ignited causing personal injury CAUTION Do not allow propane to contact the skin Propane is stored in the fuel tank as a liquid When propane contacts the atmosphere it immediately expands into a gas resulting in refrigeration that can cause severe burns CAUTION Do not allow propane to accumulate in areas below ground level such as in a service pit or under an alignment rack Propane is heavier than air and can displace oxygen creating a dangerous condition DESCRIPTION AND OPERATION PROPANE FUEL SYSTEM The primary components of the propane fuel system are the low pressure regulator fuel mixer electric lock off solenoids and engine control module ECM The system operates at pressures up to 312 psi Fuel is stored in the LPG fuel tank Propane is delivered from the tank through a lock off solenoid on the tank through an LPG fuel filter mounted on the inside of the driver side frame rail and then to the underhood low pressure lock off solenoid LPL The OEM fuel pump control circuit powers the fuel tank lock off This lock is hardwired to engine ground The AF ignition relay powers the underhood LPL The AF ECM controls the underhood lock off by opening or closing the ground circuit The lock offs which are normally closed open only when the engine is cranking or running Fuel passes through the underhood low pressure lock off solenoid to the fuel inlet on the LPR Propane enters the LPR through the
216. primary jet and into the primary chamber where the fuel is vaporized as it passes through the heat exchanger located in the center of the regulator and the pressure is reduced to approximately 2 5 psi As the fuel flows into the LPR secondary chamber the pressure is reduced to approximately negative 1 8 inches of water column When the engine is cranking or running a pressure drop is created by airflow into the engine as it passes through venturi in the fuel mixer This pressure drop is commonly referred to as air valve vacuum As air valve vacuum increases with airflow the amount of fuel drawn from the LPR secondary chamber into the mixer will also increase In the fuel mixer the propane vapor is combined with air to form a combustible Website 9 2 03 air fuel mixture The mixture is then drawn into the engine The A F mixture is controlled by the Alternative Fuel Engine Control Module AF ECM the fuel control solenoid FCS and idle control solenoid ICS The AF ECM receives input from various engine sensors to determine the amount of fuel necessary to maintain a precise air fuel mixture across the entire engine operational range The AF ECM then sends commands to the fuel control solenoid FCS and idle control solenoid ICS to meter the appropriate quantity of fuel The FCS meters the fuel flow by modulating the pressure on top of the regulator diaphragm to control fuel output pressure The ICS meters supplemental fuel flow fr
217. problem found and repaired Inspect the oxygen sensor signal and low circuits for continuity between the AF ECM connector terminals and the oxygen sensor connector terminals Inspect these circuits for shorts to other circuits or to ground Ensure the oxygen sensor PCM and the AF ECM connectors are disconnected before testing circuits Repair the wiring as necessary Was a wiring repair made Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM o TL Valet Yes be Reconnect all disconnected or removed components Using the scan tool clear all DTC information from both the PCM and the AF ECM Using the scan tool communicate with the AF ECM and reset the fuel trim values to zero Turn the ignition OFF and wait 30 seconds Start the engine View the captured freeze frame data that was stored in Step 2 Observe the data parameters that give an indication of how the vehicle was being operated when this DTC set Operate the vehicle within the conditions for running the DTC and the parameters observed when the DTC set Observe the short term fuel trim values Do the fuel trim values indicate a lean mixture condition is present or does a fuel trim DTC set Go to Step 10 Go to Step 11 Replace the fuel mixer Refer to Fuel Mixer Replacement Is the replacement complete Go to Step 12 System OK Go to Step 2 2002 LPG G Van Service Manual Supplement Page 149 Reconnect all disconnected or removed components
218. r Replacement in Engine Controls in the GM G Van service manual Is the replacement complete Important The following PCM replacement procedures must be completed before attempting to operate the vehicle 1 Replace the PCM Refer to PCM Replacement in Engine Controls in the GM G Van service manual Program flash the replacement PCM with the correct LPG software and calibration Is the replacement complete Replace the AF ECM Refer to AF ECM Replacement Is the replacement complete Using the scan tool clear the DTC information from BOTH control modules Operate the vehicle under the Conditions for Running the DTC Using the scan tool parameter DTC STATUS ensure that this DTC runs Did this DTC RUN and PASS Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM DTC P0103 DTC 37 MAF Sensor Circuit High Frequency To OEM Components Ignition Power Ground BLKANHT 451 Circuit Description The MAF sensor is an air flow meter The MAF sensor is supplied with ignition voltage and a ground The MAF sensor heats a wire grid within the sensor to a predetermined temperature As inlet air flow across and cools the wire grid the MAF sensor must increase current flow to the wire grid to maintain a constant temperature The MAF sensor converts the required wire grid current flow into a frequency signal The PCM and the AF ECM monitor the MAF signal circuit frequency and determine the flow and mass of the
219. r Connector C451 Connector Part 12129615 Information 3 way Metri Pack Sealed 150 Series BLK Circuit No A Fuel Pump Relay Power RY BLK 1589 Fuel Level Sensor Signal 2002 LPG G Van Service Manual Supplement Page 22 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM AF Engine Scan Tool Data List Engine Idling Radiator Hose Hot Closed Throttle Park or Neutral Closed Loop Accessories Off Scan Tool Parameter Parameter Range Units Typical Data Values Engine Speed 0 10 000 RPM 500 700 RPM Open Closed HO2S Bank 1 Sensor 1 0 1000 mV Varies between 100 900 mV Short Term Fuel Trim Bank Near 0 20 Long Term Fuel Tim Bank 1 Near 0 20 IAT Sensor 39 to 140 C 38 to 284 F 35 C 91 F Depending on ambient temperature ECT Sensor 39 to 140 C 38 to 284 F 88 to 105 C 190 to 221 F Engine Load 0 100 HO2S Bank 2 Sensor 1 0 1000 mV Varies between 100 900 mV Verice Speed Sens ifr mp t Command DEE o UH Low Pressure Lock of Alternativo Fuel Run Time Log 0 100 AF ECM Output Driver Data E AOS ee ECM 7 FO Signal Command Il em 1 02 0 V All Fuel MIL Command ONT OFF AFO Signal Command AF ECM OFF 2002 LPG G Van Service Manual Supplement Page 23 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM AF Diagnostic Trouble Code DTC List DTC P0107 34 Manifold Absolute Pressure MAP Sensor Circuit Low Voltage DTC P0108
220. rence circuit is the cause of the condition The 4 8 volts is the minimum output that the PCM should supply on the 5 volt reference circuit DTC P0122 TP Sensor Circuit Low Voltage Did you perform the Alternative Fuels AF Powertrain On Board Diagnostic OBD System Check 1 Turn the ignition ON with the engine OFF 2 Using the scan tool establish communication with the PCM 3 Observe the TP sensor data parameter Does the TP sensor data parameter indicate TP voltage less than the specified value 1 Using the scan tool establish communication with the AF ECM 2 Observe the TP sensor data parameter Does the TP sensor data parameter indicate TP voltage less than the specified value Open and close the throttle while observing the TP sensor data parameter Does the TP sensor data parameter ever indicate TP voltage less than the specified value The fault is not present Refer to Diagnostic Aids Are there any DTCs stored that have not been diagnosed Website 9 2 03 Value s Yes No Go to AF Powertrain OBD System Go to Step 2 Check 0 09 volts Go to Step 6 Go to Step 3 0 09 volts Go to Step 14 Go to Step 4 Go to Step 6 Go to Step 5 Go to AF DTC List Go to Intermittents 2002 LPG G Van Service Manual Supplement Page 91 QUANTUM PROPANE FUEL SYSTEM value s Disconnect the TP sensor connector 2 Jumper the 5 volt reference circuit terminal to the TP signal circuit ter
221. resent This DTC may have been set by one of the following conditions An intermittently open or high resistance HO2S high signal circuit or low circuit An intermittently open or high resistance HO2S heater feed or ground circuit A faulty HO2S or gasoline PCM terminal contact A defective HO2S Repair any of the above conditions as necessary Was a condition found and repaired Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Step Aeen Vale Yes mo Disconnect the test lamp Jumper the HO2S low circuit terminal to a known good ground Jumper the HO2S high circuit terminal to a known good ground Use the scan tool to monitor the HO2S B1 S1 20 mV voltage Ensure the ignition is ON while the engine is OFF ifi Is the voltage less than the specified range Go to Step 10 Go to Step 9 Connect the test lamp between the HO2S heater ignition feed circuit terminal engine harness side and a known good ground Ensure the ignition is ON while the engine is OFF Does the test lamp illuminate Go to Step 11 Go to Step 12 Turn the ignition OFF Remove the jumpers from the HO2S terminals Disconnect the PCM connector containing the HO2S high and low circuits Using a DVOM measure the continuity of the HO2S high signal circuit and the HO2S low signal circuit between the PCM and the HO2S connector terminal engine harness side Are both resistances less than the specified value Go to Step
222. rive trips that the diagnostic runs and fails The AF ECM will record operating conditions at the time the DTC sets This information will be stored as Freeze Frame data Conditions for Clearing the MIL DTC e The Last Test Failed status will clear when the DTC runs and passes 2002 LPG G Van Service Manual Supplement Page 61 QUANTUM PROPANE FUEL SYSTEM e The AF ECM will turn OFF the MIL after THREE DTCs were stored proceed to the applicable DTC consecutive drive trips that the DTC runs and table in the order stated in the OBD System Check passes e The History status will clear after FORTY Test Description consecutive WARM UP cycles with NO failures The numbers below refer to the step numbers on the of ANY DTC diagnostic table e All information can be cleared using a scan tool e Interruption of Control Module AF ECM PCM 2 This step determines if the failure condition affects power and ground MAY clear DTC information the PCM Clearing DTC information with this method is 3 This step determines if the failure condition is inconsistent and should not be performed present 5 This step determines if the MAP sensor is the Diagnostic Aids cause of the condition 6 This step determines if the volt reference circuit Fault Not Present is the cause of the condition 4 8 volts is the Fault Not Present indicates the condition that minimum output that the PCM should supply to the 5 caused the DTC to set is intermittent
223. rnative Fuel i Control i Engine Control 1 ECT Sensor IAT Sensor 5 Volt 5Volt 1 Module f ECT Sensor IAT Sensor 5 Volt Module 1 Signal Signal Reference Reference PCM 1 Vi EE Signal D Zens __ AF ECM 74 C1 BLU 25 C2 RED 8 48 C1 BLU 12 N 13 29 C002 BLU YEL 410 GRY 2704 TAN 472 YEL 410 TAN 472 GRY 2701 A B D YEL 017 410 TAN YEL 410 S018 472 TAN 472 GRY 022 A 2704 GRY 2704 A C Engi Intake Ai ee Temperature Throttle Men wod Sensor Position Pressure TP MAP Sensor Sensor A B A B LT GRN 432 LT GRN DK BLU 417 ORN BLK 469 020 ORN BLK 021 BLK 2761 BLK 2760 BLK 2752 D 469 S019 DK BLU ORN BLK 469 A S E DK BLU 417 s y C005 LT GRN 432 ORN C1 c2 C1 C1 pk BLU 417 P rend 432 ni A alen sey come ale elen my omen i Sensor Sensor Sensor TP Sensor Sensor MAP Sensor 4 i TP Sensor Sensor MAP Sensor 1 l Ground Ground Ground Signal Ground Signal 1 Signal Ground Signal 1 1 GE E Powertrain Control Module PCM Alternative Fuel Engine Control Module AF ECM VSS less than 5 MPH Conditions for Setting the DTC The AF ECM monitors a MAP sensor signal voltage of less than 0 098 volts for at least 4 seconds continuously Action Taken When the DTC Sets A first failure of this DTC will NOT illuminate the MIL and will store as Last Test Failed but not as History The AF ECM will illuminate the MIL and store the DTC as History after TWO consecutive d
224. rom the AF ECM in the scan tool Inspect both the AF ECM and the PCM for other stored DTCs Are other DTCs stored Perform the other DTC diagnosis before attempting diagnosis of this DTC Is the other DTC diagnosis and or repair complete The condition that set this DTC is not present This DTC may have been set by one of the following conditions A signal wire intermittently shorted to voltage HO2S connector water intrusion A silicon contaminated HO2S An rich condition such as the following Faulty Idle Control Solenoid ICS or ICS circuit Faulty Fuel Control Solenoid FCS or FCS circuit Incorrect LPG fuel pressure Low coolant level cooling system not bled at LPR Leaking low pressure regulator LPR Rich condition at fuel mixer An inaccurate MAF sensor A restricted air filter or air intake duct Repair any of the above conditions as necessary Was a condition found and repaired Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Sep Rio Lie Yes No Reconnect all disconnected or removed components Using the scan tool clear all DTC information form both the PCM and the AF ECM Using the scan tool communicate with the AF ECM and reset the fuel trim values to zero Turn the ignition OFF and wait 30 seconds Start the engine View the captured freeze frame data that was stored in Step 2 Observe the data parameters that give an indication of how the vehicle was being operated when this DTC set
225. rtant Preliminary Checks Fuel System Checks Check the fuel pressure Refer to AF Fuel System Diagnosis Check for low fuel pressure during a moderate or full throttle acceleration If the fuel pressure drops below specification there is possibly a faulty low pressure regulator or a restriction in the fuel system Check the Manifold Absolute Pressure MAP sensor response and accuracy Check the mixer air valve for sticking or binding Check the mixer module assembly for proper installation and leakage Check the FCS ICS connections Ignition System Checks Note LPG being a gaseous fuel requires higher secondary ignition system voltages for the equivalent gasoline operating conditions If a problem is reported on LPG and not gasoline do not discount the possibility of a LPG only ignition system failure and test the system accordingly Check for the proper ignition voltage output with J 26792 or the equivalent Verify that the spark plugs are correct Check for faulty spark plug wires Check for fouled spark plugs Check for an open ignition system ground Refer to Enhanced Ignition System in the GM G Van Service Manual Additional Check Check for Service Bulletins Check for manifold vacuum or air induction system leaks Check the generator output voltage Check the EGR valve operation Refer to EGR System Diagnosis in the GM G Van Service Manual 2002 LPG G Van Service Manual Supplement Page 174 Website 9 2 03 QUAN
226. rvice Manual Supplement Page 159 QUANTUM PROPANE FUEL SYSTEM Conditions for Clearing the MIL DTC e Rubbed through wire insulation e The Last Test Failed status will clear when the e A broken wire inside the insulation DTC runs and passes e The AF ECM will turn OFF the MIL after THREE Fault Not Present consecutive drive trips that the DTC runs and Fault Not Present indicates the condition that passes caused the DTC to set is intermittent and currently e The History status will clear after FORTY present Refer to ntermittents in Symptom diagnosis consecutive WARM UP cycles with NO failures for additional information If any additional DTCs of ANY DTC were stored proceed to the applicable DTC table in e All information can be cleared using a scan tool the order stated in the OBD System Check e Interruption of Control Module AF ECM PCM power and ground MAY clear DTC information Test Description Clearing DTC information with this method is The numbers below refer to the step numbers on the inconsistent and should not be performed diagnostic table 2 This step determines if the DTC P0500 is the Diagnostic Aids result of a hard failure or an intermittent condition Thoroughly check the sensor wiring if the complaint 5 This step checks the wiring the connections the is intermittent An intermittent may be caused by any PCM and the VSS of the following e A poor connection DTC P0500 DTC 24 Vehicle Speed Sensor VSS Circui
227. ry e The AF ECM will illuminate the MIL and store the DTC as History TWO consecutive drive trips that the diagnostic runs and fails e The AF ECM will record operating conditions at the time the DTC sets This information will be stored as Freeze Frame data Conditions for Clearing the MIL DTC e The Last Test Failed status will clear when the DTC runs and passes e The AF ECM will turn OFF the MIL after THREE consecutive drive trips that the DTC runs and passes e The History status will clear after FORTY consecutive WARM UP cycles with NO failures of ANY DTC e All information can be cleared using a scan tool QUANTUM PROPANE FUEL SYSTEM Interruption of Control Module AF ECM PCM power and ground MAY clear DTC information Clearing DTC information with this method is inconsistent and should not be performed Diagnostic Aids Check for the following condition Low or empty LPG fuel tank For proper LPG fuel system operation liquid fuel is required at the LPR inlet If the fuel level becomes so low that fuel vapor is delivered to the LPR inlet the air fuel mixture will be lean and the MIL may illuminate Also the vehicle will start and idle normally but hesitate and stumble under load If the DTC is current verify that the fuel tank is at least Y4 full If the DTC is stored in history verify with the operator if the vehicle has recently been run low or out of fuel Fault Not Present Fault Not Present indicat
228. s This information will be stored as Freeze Frame data Conditions for Clearing the MIL DTC The Last Test Failed status will clear when the DTC runs and passes 2002 LPG G Van Service Manual Supplement Page 58 QUANTUM PROPANE FUEL SYSTEM e The AF ECM will turn OFF the MIL after THREE consecutive drive trips that the DTC runs and passes e The History status will clear after FORTY consecutive WARM UP cycles with NO failures of ANY DTC e Al information can be cleared using a scan tool e Interruption of Control Module AF ECM PCM power and ground MAY clear DTC information Clearing DTC information with this method is inconsistent and should not be performed Diagnostic Aids Fault Not Present Fault Not Present indicates the condition that caused the DTC to set is intermittent and not currently present Refer to Intermittents in Symptom diagnosis for additional information If any additional DTCs were stored proceed to the applicable DTC table in the order stated in the OBD System Check Test Description The numbers below refer to the step numbers on the diagnostic table 2 This step tests the MAP sensor s ability to correctly indicate BARO To determine the correct MAP sensor display of BARO for any elevation perform either of the following Compare the recorded MAP sensor display value to the BARO display on a know good vehicle Or Obtain local weather service barometer reading in Hg Multiply th
229. s ground and probe pin A of the LPL connector 3 Crank the engine The test light should illuminate Does the test light illuminate Go to Step 24 Go to Step 25 Does the test light illuminate Go to Step 18 Go to Step 23 Using a DVOM check the resistance of the fuel tank lock off 162 2090 Is the resistance within the specified range Go to Step 19 Go to Step 27 CAUTION When disconnecting LPG fuel lines liquid LPG may be present Perform this step in a well ventilated area 1 Loosen the fuel inlet hose fitting at the outlet of the fuel tank lock off iti 2 Was fuel present when the fitting was loosened Go to Step 21 Go to Step 27 The fuel supply system or hoses are plugged or Go to Step 30 restricted Locate and repair the problem Is the action complete 2002 LPG G Van Service Manual Supplement Page 40 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM See Action O Vawis Ye No Go to Step 22 Go to Step 20 Remove the LPG fuel filter Go to Step 30 Empty the contents of the inlet side of the LPG fuel filter onto a clean surface Inspect the contents of the LPG fuel filter for an excessive amount of foreign material or water If necessary locate and repair the source of contamination Verify the LPG fuel filter is not restricted or plugged Was a problem found Replace the fuel filter Refer to Fuel Filter Replacement Is the action complete Repair the open in the lock off ground circui
230. s the TP sensor data parameter indicate TP voltage greater than the specified value Depress the throttle slowly to wide open throttle WOT Does the scan tool display the throttle angle above the specified value Release the throttle Does the scan tool display the throttle angle below the specified value Website 9 2 03 Value s ves Ne Go to AF Powertrain OBD System 2 Go to Step Check 296 Go to Step 3 Go to Step 6 Go to Step 4 Go to Step 6 Go to Step 5 Go to Step 6 2002 LPG G Van Service Manual Supplement Page 86 QUANTUM PROPANE FUEL SYSTEM Sep Agen LL Vew g Yes Ne The fault is not present Refer to Diagnostic Aids Are there any DTCs stored that have not been Go to Go to diagnosed AF DTC List Intermittents Disconnect the TP sensor harness connector Other DTCs may be set Connect a fused jumper between the TP signal circuit and the 5 volt reference circuit terminal 4 9 volts Observe the TP sensor voltage data parameter Does the TP sensor data parameter indicate TP Go to Step 7 Go to Step 10 voltage greater than the specified value Remove the fused jumper Connect the DVOM test leads between the TP sensor 5 volt reference circuit terminal and a 4 8 5 2 volts known good ground Measure the voltage on the 5 volt reference circuit Zb Go to Step 8 Go to Step 12 Is the voltage within the specified range Using a fused jumper connect the TP sensor signal ter
231. signal voltage temperature for at least 30 seconds The engine that is below the normal operating range of the coolant temperature must be greater than 50 C sensor AND the mass air flow above 4 4 gms sec for at During normal closed loop operation the AF ECM least 30 seconds for the AF ECM to determine will add fuel richen the mixture when the HO2S the HO2S is at operating temperature indicates a lean exhaust The AF ECM will remove fuel lean the mixture when the HO2S indicates a rich exhaust This oscillation above and below the 2002 LPG G Van Service Manual Supplement Page 135 Website 9 2 03 Conditions for Setting the DTC The AF ECM monitors an HO2S signal voltage stuck between 0 300 V and 0 600 V in active for 8 seconds continuously OR The AF ECM monitors an HO2S signal voltage between 0 00 V and 1 0 V that has not performed a rich lean switch for 8 seconds continuously Action Taken When the DTC Sets The AF ECM will control fuel trim based upon the Bank 1 Sensor 1 signal If a Bank 1 Sensor 1 DTC sets the AF ECM will operate in open loop fuel control e A first failure of this DTC will NOT illuminate the MIL and will store as Last Test Failed but not as History e The AF ECM will illuminate the MIL and store the DTC as History TWO consecutive drive trips that the diagnostic runs and fails e The AF ECM will record operating conditions at the time the DTC sets This information will be stored as Freeze Fra
232. stance when hot The PCM supplies about 5 volts on the ECT signal circuit The Conditions for Setting the DTC PCM also supplies a ground circuit to the ECT sensor When ECT resistance is high cold sensor The AF ECM monitors an ECT sensor signal voltage the ECT signal voltage remains near the supplied 5 of less than 0 019 volts for at least 5 seconds volts As the ECT sensor warms and resistance continuously drops signal voltage is pulled lower to the sensor ground The PCM and the AF ECM monitor the ECT Action Taken When the DTC Sets signal circuit voltage to determine engine temperature e A first failure of this DTC will NOT illuminate the This DTC is used to indicate an ECT signal voltage MIL and will store as Lest Test Failed but not as that is above the normal operating range of the History sensor This is a type B DTC e The AF ECM will illuminate the MIL and store the DTC as History after TWO consecutive drive trips that the diagnostic runs and fails e The AF ECM will record operating conditions at the time the DTC sets This information will be stored as Freeze Frame data 2002 LPG G Van Service Manual Supplement Page 77 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Conditions for Clearing the MIL DTC currently present Refer to Intermittents in Symptom diagnosis for additional information If any additional e The Last Test Failed status will clear when the DTCs were stored proceed to the applicable DTC DTC runs and passes
233. system to measure actual engine coolant temperature Start and idle the engine Allow the engine to operate until the ECT sensor data parameter no longer increases temperature has stabilized Observe the ECT sensor data parameter Measure the actual engine coolant temperature Compare the ECT sensor data parameter to Go to Step 6 Go to Step 9 actual engine coolant temperature Does the ECT sensor data parameter indicate a temperature near the actual engine coolant temperature 1 Inspect the ECT signal circuit for a shorted or low resistance to ground condition 2 Repair wiring or terminals as necessary Go to Step 11 Go to Step 10 Go to Step 11 Goto Step 10 Go to Step 11 gt Go to Step 11 Ei 2002 LPG G Van Service Manual Supplement Page 100 Was a wiring or terminal repair made Inspect the ECT signal and ground circuits for an open or high resistance condition Inspect the PCM connector the AF ECM connector and the ECT sensor connector for proper terminal contact Repair wiring or terminals as necessary Was a wiring or terminal repair made Replace the ECT sensor Refer to ECT Sensor Replacement in the GM G VAN service manual Is the replacement complete Replace the AF ECM Refer to AF ECM Replacement The fault is not present Refer to Diagnostic Aids Go to Go to 2 Are any DTCs stored that have not been diagnosed AF DTC List intermittents Is the replacement complete W
234. t Vues Yes We _ Did you perform the Alternative Fuels AF Powertrain Go to AF On Board Diagnostic OBD System Check Powertrain OBD System Go to Step 2 Check Connect the scan tool Clear the AF ECM DTCs Using a DVOM backprobe across the VSS signal circuits high and low Raise the rear wheels of the vehicle Refer to Lifting and Jacking the Vehicle in General Information in the GM G Van service manual Operate the engine in gear Observe the VSS reading on the scan tool Does the scan tool read the vehicle speed Go to Step 3 Go to Step 4 Go to Diagnostic The fault is intermittent Aids Remove the engine from gear Using a DVOM set to the AC 200V scale backprobe cavity B of 10 way inline connector C004 Operate the engine in gear Does the voltage vary with RPM Go to Step 6 Go to Step 5 2002 LPG G Van Service Manual Supplement Page 160 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Sep tion Vawis Wes No 7 Go to Step 8 Go to Step 10 Remove the engine from gear Go to Step 7 Go to Step 8 Unplug the 10 way inline connector C004 Check the VSS circuit Pin B for short to ground Go to Step 11 Go to Step 9 Go to Step 11 or short to power on the AF harness side Was a problem found Backprobe Pin 15 of the AF ECM connector C002 Operate the engine in gear Does the voltage vary with RPM Check for a poor connection Pin 15 of the AF ECM connector C002 Was a problem foun
235. t Go to Step 30 uN Go to Step 30 E Go to Step 30 ES Is the action complete Repair the open in the lock off power OEM fuel pump circuit Is the action complete Replace the low pressure regulator LPR Refer to Low Pressure Regulator Replacement Is the action complete Replace the lock off Refer to applicable fuel tank or underhood Low Pressure Lock off LPL Replacement Is the action complete Replace the mixer and elbow assembly Refer to Fuel Mixer Replacement Go to Step 30 Go to Step 30 Is the action complete 1 Turn OFF the ignition 2 Connect the test light to chassis ground and probe pin A of the LPL connector 3 Crank the engine The test light should illuminate Does the test light illuminate Go to Step 24 Go to Step 25 2002 LPG G Van Service Manual Supplement Page 41 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Sep Action O vao Yes No The fuel supply system is operating normally if a failure of the control solenoids is suspected Refer to AF Fuel Control System Diagnosis 1 Install the test plug in the LPR secondary chamber 2 f you were sent to this routine by another diagnostic chart return to the previous diagnostic procedure Is the action complete System OK Disconnect all test equipment Install the primary and secondary test port plugs Start the engine Using SNOOP 6 or equivalent leak check the test port plugs Is the action complete
236. t Page 31 1 Turn ON the ignition with the engine OFF 2 Observe the MIL Input PCM data parameter on the scan tool Is a PCM MIL Input request present Turn OFF the ignition and wait 30 seconds Disconnect the AF ECM connectors Turn ON the ignition with the engine OFF Connect a fused jumper between the Mil Control AF ECM circuit terminal and a known good ground If the jumper fuse opens repair the short to voltage in the AF ECM MIL Control circuit Is the MIL illuminated Crank the engine for at least 10 seconds Does the engine start and run Go to Step 7 Go to Step 10 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM aer Aci T Values Go to Step 20 The fault is in PCM system Refer to Powertrain On Board Diagnostic System Check in the G Van Truck Go to Step 20 Goto Step 17 Go to Step 20 Go to Step 19 service manual Are all diagnosis and repairs of the OEM PCM system complete Test the MIL Control circuit between the AF ECM connector terminal and the IP for a short to ground Test the IP for an internally shorted condition Repair the circuit or IP as necessary Was a repair necessary 1 Test the MIL input circuit between the AF ECM connector terminal and the PCM connector terminal for a short to ground 2 Repair the circuit as necessary Was as circuit repair necessary 1 Test the MIL Input circuit between the AF ECM connector terminal and the PCM for an open or short to vo
237. t operating temperature will cause the HO2S signal voltage to go above or below depending upon exhaust oxygen content the bias voltage This DTC is used to indicate an HO2S signal voltage that did not leave the cold sensor bias voltage range in an acceptable amount of time This DTC is a type B DTC Conditions for Running the DTC e AF ECM DTCs P0117 15 P0118 14 P0125 16 P0131 44 P0132 45 P0134 42 are not set e The start up engine coolant temperature is less than 91 F 33 C 2002 LPG G Van Service Manual Supplement Page 119 e The engine has been operating for at least five seconds e The average mass air flow is less than 35 grams per second e All other AF ECM DTCs for this HO2S sensor have ran and passed e This DTC has not tested this ignition cycle e The AF ECM determines the HO2S was cold at ignition key ON The average HO2S signal voltage must be within the bias voltage range of 0 30 volts 300 mV to 0 60 volts 600 mV for the AF ECM to determine the HO2S was cold Conditions for Setting the DTC The AF ECM monitors an HO2S signal voltage that did not leave the cold sensor bias voltage range of 0 30 volts 300 mV to 0 060 volts 600 mV in an acceptable amount of time The time varies from 50 seconds to 110 seconds based upon mass air flow Action Taken When the DTC Sets e A first failure of this DTC will NOT illuminate the MIL and will store as Last Test Failed but not as Histo
238. t the PCM connector 3 Disconnect ECM connector C002 4 Using a DVOM check for continuity of the CKP sensor signal circuit between the PCM and ECM Was a problem found Check for a short to ground or short to ignition power in the CKP signal circuit Check for a load on the CKP signal circuit malfunctioning tachometer Check for proper pin tension at the PCM connector Goto DTC PO336 CKP Sensor Circuit Performance in the GM G Van Service Go to Step 10 Manual Go to Step 8 Go to Step 9 Go to Step 10 Go to Step 10 ES Go to Step 11 Go to Step 2 2002 LPG G Van Service Manual Supplement Page 157 Was a problem found and repaired Inspect the ECM connector and pins Was a problem found Repair the open or damaged circuit Is the action complete Replace the ECM Refer to ECM Replacement Is the action complete 1 Clear the DTC 2 Operate the vehicle within the conditions for setting this DTC as specified in the supporting text 3 Check to see if the MIL still illuminates Did the diagnostic run and pass Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM No Are any ECM or PCM DTCs stored that have not Go to the been diagnosed applicable DTC table System OK 2002 LPG G Van Service Manual Supplement Page 158 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM DTC P0500 DTC 24 Vehicle Speed Sensor VSS Circuit Alternative Fuels Engine Speed Operation AFO TACH Signal C
239. table should measure infinite with all components 4 The engine may also have a higher than normal disconnected form the circuit idle if a vacuum leak is present 9 The step determines if a base engine concern is 8 When testing the circuits for continuity the causing the rich condition resistance should be less than 5 ohms When DTC P0171 DTC 55 Fuel Trim System Lean Sep Ado O Vas Yes Ne Go to AF Powertrain OBD System heck Go to Step 2 SE Did you perform the Alternative Fuels AF Powertrain Go to Step 3 Goto Step 4 On Board Diagnostic OBD System Check Go to Step 12 Go to Step 12 Go to Step 5 2002 LPG G Van Service Manual Supplement Page 147 Connect the scan tool Capture the DTC information from the AF ECM in the scan tool Inspect both the AF ECM and the PCM for other stored DTCs Are other DTCs stored Perform the other DTC diagnosis before attempting diagnosis of this DTC Is the other DTC diagnosis and or repair complete The condition that set this DTC is not present This DTC may have been set by one of the following conditions A signal wire intermittently open or shorted to ground HO2S connector water intrusion A lean condition such as the following Incorrect LPG fuel pressure Vacuum leaks Faulty Idle Control Solenoid ICS or ICS circuit Faulty Fuel Control Solenoid FCS or FCS circuit A restricted low pressure regulator LPR A lean fuel mixer An inaccur
240. table in the order stated in the OBD System Check e The AF ECM will turn OFF the MIL after THREE consecutive drive trips that the DTC runs and Test Description passes The numbers below refer to the step numbers on the e The History status will clear after FORTY diagnostic table consecutive WARM UP cycles with NO failures 2 This step determines if the failure condition is of ANY DTC present e All information can be cleared using a scan tool 5 This step determines if the ECT sensor is e Interruption of Control Module AF ECM PCM shorted AS power and ground MAY clear DTC information 6 This step determines if a short is present in the Clearing DTC information with this method is wiring harness inconsistent and should not be performed 7 This step determines if the PCM or the AF ECM is the cause of the shorted condition Diagnostic Aids 8 This step determines if an open circuit condition is present between the PCM and AF connector Fault Not Present C005 Fault Not Present indicates the condition that caused the DTC to set is intermittent and not DTC P0117 DTC 15 ECT Sensor Circuit Low Voltage Stp ee Values Did you perform the Alternative Fuels AF Powertrain On Board Diagnostic OBD System Check Go to AF Powertrain OBD System heck Go to Step 2 SEN 1 Using the scan tool establish communication with the AF ECM 2 Observe the ECT sensor data parameter 0 019 volts Does the ECT sensor data parameter indicate
241. tart Records data 7 Comparison of an actual control system data with e If the AF ECM has stored DTC P0601 DTC 58 the Typical Scan Tool Data Values is a quick along with multiple DTCs go to DTC P0601 check to determine if any parameter is not within DTC 58 AF ECM Internal Failure first limits A base engine problem i e advanced Intermittent power or ground connections may cam timing may substantially alter sensor value Alternative Fuel AF Powertrain OBD System Check with Scan Tool al n O ves e IW Important e Check for applicable service bulletins before proceeding with this test e Do not clear DTCs unless instructed by this diagnostic 1 Turn off the ignition 2 Connect the scan tool 3 Turn ON the ignition with the engine OFF Go to Malfunction Does the MIL illuminate Go to Step 2 ips d ramp ircuit 2002 LPG G Van Service Manual Supplement Page 25 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM se n Values ves Ne Using a scan tool attempt to communicate and Go to A Power retrieve data from the PCM If the scan tool fails to train On Board turn ON refer to Test Descriptions Diagnostic OBD System Check in the GM G Van Go to Step 3 service manual Go to Step 4 Go to Step 8 Go to Step 9 Go to Step 5 Does the scan tool display PCM data Using a scan tool attempt to communicate and retrieve data from the AF ECM Does the scan tool display AF ECM data Inspect
242. tent and should not be performed Diagnostic Aids For this DTC the AF ECM uses MAF sensor airflow values to determine when the engine is cranking or running The PCM uses cam sensor pulses for the PCM DTC An AF ECM DTC but not a PCM DTC would result during any condition such as a disconnected MAF sensor that causes airflow to be indicated with the ignition ON and the engine OFF Fault Not Present Fault Not Present indicates the condition that caused the DTC to set is intermittent and not currently present Refer to Intermittents in Symptom diagnosis for additional information If any additional DTCs were stored proceed to the applicable DTC table in the order stated in the OBD System Check Preliminary Checks Check for the following conditions e Apoor connection a rubbed through wire insulation or a wire that is broken inside the insulation may cause an intermittent problem e Inspect harness connectors for the following conditions Backed out terminals Improper mating Broken locks Improperly formed or damaged terminals Poor terminal to wire connection Physical damage to the wiring harness Inspect the face of the CKP sensor for metal shavings This could result in an intermittent DTC Refer to Intermittents in the powertrain diagnostics manual Test Description The numbers below refer to the step numbers on the diagnostic table 2 This step determines if the DTC is the result of a hard
243. ter indicate ECT voltage less than the specified value Go to Step 8 Goto Step 6 Connect the fused jumper between the ECT sensor signal circuit and a good known ground 0 019 volts Does the ECT sensor data parameter indicate ECT voltage less than the specified value Go to Step 9 Go to Step 7 Turn the ignition OFF Disconnect the PCM connector that contains the Go to Step 11 Goto Step 10 Go to Step 17 ECT sensor signal circuit With the ECT sensor connector disconnected test the ECT signal circuit for continuity Is ECT signal circuit continuity indicated Replace the ECT sensor Refer to ECT Sensor Replacement in Engine Controls in the GM G VAN service manual Is the replacement complete Repair the open ECT signal circuit between the ECT sensor connector and the PCM Is the circuit repair complete 1 Inspect for proper terminal contact at the PCM connector 2 Repair the terminal as necessary Go to Step 17 Ed Go to Step 17 mE Go to Step 14 Go to Step 13 2002 LPG G Van Service Manual Supplement Page 83 Was a terminal repair made Turn the ignition OFF Disconnect the AF ECM connector C002 With the ECT sensor connector disconnected test the ECT signal circuit for continuity Repair the open sensor ground circuit between the ECT sensor connector and the PCM Is the circuit repair complete Go to Step 17 Is ECT signal circuit continuity indicated Website 9 2 03 QUANTUM PROPANE FUEL
244. termines if the ECT sensor is accurately monitoring engine coolant temperature DTC P0125 DTC 16 ECT Excessive Time to Closed Loop Did you perform Alternative Fuels AF Powertrain On Board Diagnostic OBD System Check Verify proper cooling system and thermostat operation Refer to Engine Cooling in the GM G VAN service manual Is the resistance below the specified value Using the scan tool establish communication with the AF ECM Disconnect the ECT sensor Observe the ECT sensor data parameter Does the ECT sensor data parameter indicate ECT voltage greater than the specified value Connect a 1 amp fused jumper between the ECT sensor connector signal and ground circuit terminals Does the ECT sensor data parameter indicate ECT voltage less than the specified value Website 9 2 03 Go to AF Powertrain OBD System ER Go to Step 2 os P Go to Step 11 Go to Step 3 4 9 volts Go to Step 4 Go to Step 7 0 019 volts Go to Step 5 Go to Step 8 2002 LPG G Van Service Manual Supplement Page 99 QUANTUM PROPANE FUEL SYSTEM Sep tion Value S No 1 Reconnect the ECT sensor connector CAUTION To avoid being burned do not remove the radiator cap or surge tank while the engine is hot The cooling system will release scalding fluid and steam under pressure if the radiator cap or surge tank cap is removed while the engine and radiator are still hot Install a thermometer in the engine cooling
245. the MAF sensor data parameter with the 0 0 kHz engine idling Does the MAF sensor data parameter indicate frequency greater than the specified value Go to Step 7 Go to Step 10 A high frequency signal may be induced on the MAF Go to Step 11 Go to Step 9 signal circuit by sources other than the MAF sensor Inspect the vehicle for the following conditions A MAF signal circuit routed near secondary ignition components A MAF signal circuit routed near high current components motors relays etc High power transceivers operating in or near the vehicle Route wiring harness correctly or remove the source of high frequency Was an induced high frequency source found and corrected Important The following PCM replacement procedures must be completed before attempting to operate the vehicle 1 Replace the PCM Refer to PCM Replacement in Engine Controls in the GM G Van service manual Program flash the replacement PCM with the correct LPG software and calibration Is the replacement complete Replace the AF ECM Refer to AF ECM Replacement Replace the MAF sensor Refer to MAF Sensor Replacement in Engine Controls in the GM G Van service manual Is the replacement complete Go to Step 11 Is the replacement complete Go to Step 11 2002 LPG G Van Service Manual Supplement Page 56 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM sien ton w ves w Using the scan tool clear the DTC information fro
246. the negative battery cable Disconnect the MAF and IAT sensor electrical connectors Remove the air cleaner housing with MAF sensor Remove the inlet bellows and from the elbow cover Remove the IP lower trim panel from the IP Remove the center consol mounting hardware Disconnect the electrical connectors for the lighter accessory plug and storage compartment lamp Remove the center consol Release the engine cover retaining straps and remove the cover Remove the one 1 elbow to throttle boy nut Remove the two 2 upper elbow support bracket bolts Website 9 2 03 12 13 14 15 16 Loosen the one 1 lower elbow support bracket bolt Disconnect the PCV hose from the elbow Disconnect the two 2 vacuum hoses from the elbow Remove the fuel vapor hose clamp Remove the fuel mixer outlet elbow cover assembly from the throttle body Installation Procedure 1 Install the fuel mixer outlet elbow cover assembly to the throttle body while connecting the fuel vapor hose Install the fuel vapor hose clamp e Tighten the clamp to 2 Nem 18 Ib in Connect the two 2 vacuum hoses to the elbow Connect the PCV make up air hose to the elbow cover Install the one 1 elbow to throttle body nut e Tighten the nut to 4 Nem 36 Ib in Tighten the one 1 lower elbow support bracket bolt e Tighten the bolt to 28 Nem 21 lb ft Install the two 2 upper elbow support bracket bolts e Tighten th
247. the time the DTC sets This information will be stored as Freeze Frame data Conditions for Clearing the MIL DTC e The Last Test Failed status will clear when the DTC runs and passes e The AF ECM will turn OFF the MIL after THREE consecutive drive trips that the DTC runs and passes e The History status will clear after FORTY consecutive WARM UP cycles with NO failures of ANY DTC e All information can be cleared using a scan tool e Interruption of Control Module AF ECM PCM power and ground MAY clear DTC information Clearing DTC information with this method is inconsistent and should not be performed Diagnostic Aids Fault Not Present Fault Not Present indicates the condition that caused the DTC to set is intermittent and not currently present Refer to Intermittents in Symptom diagnosis for additional information If any additional DTCs were stored proceed to the applicable DTC table in the order stated in the OBD System Check Always diagnose ANY PCM codes that are present before beginning this diagnostic procedure Check the following items e Faulty Idle Control Solenoid ICS or ICS circuit e Faulty Fuel Control Solenoid FCS or FCS circuit e Faulty fuel mixer e Faulty LPR Test Description The numbers below refer to the step numbers on the diagnostic table 4 An HO2S contaminated by silicon will have a white powdery deposit on the portion of the HO2S that is exposed to the exhaust stream The us
248. tion should be diagnosed before replacing the PCM DTC P0118 DTC 14 ECT Sensor Circuit High Voltage Did you perform the Alternative Fuels AF Powertrain On Board Diagnostic OBD System Check 1 Using the scan tool establish communication with the PCM 2 Observe the ECT sensor data parameter Does the ECT sensor data parameter indicate ECT voltage greater than the specified value 1 Using the scan tool establish communication with the AF ECM 2 Observe the ECT sensor data parameter Does the ECT sensor data parameter indicate ECT voltage greater than the specified value The fault is not present Refer to Diagnostic Aids Are there any DTCs stored that have not been diagnosed Website 9 2 03 Value s Ye m Go to AF Powertrain OBD System Go to Step 2 Check 4 9 volts Go to Step 5 Go to Step 3 Go to Step 12 Go to Step 4 Go to AF DTC List 4 9 volts Go to Intermittents 2002 LPG G Van Service Manual Supplement Page 82 QUANTUM PROPANE FUEL SYSTEM Step Action Values Yes X No Disconnect the ECT sensor Connect a fused jumper between the ECT sensor connector terminals Note If the fuse of the jumper opens repair the short to 0 019 volts voltage in the ECT sensor signal circuit If a short to voltage condition is observed inspect the sensor for and open condition for an open after the wiring repair is made Does the ECT sensor data parame
249. trols in the GM G VAN service manual Is the replacement complete Go to Step 15 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Sep Rio Lie Yes No Reconnect all disconnected or removed components connectors LPL test jumper fuses etc Using the scan tool clear the DTC information from BOTH control modules Using the scan tool communicate with both control modules to reset the fuel trim values to zero Operate the vehicle under the Conditions for Running the DTC Using the scan tool parameter DTC STATUS ensure that this DTC runs Did this DTC RUN and PASS System OK Go to Step 2 2002 LPG G Van Service Manual Supplement Page 112 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM P0134 DTC 42 HO2S Insufficient Activity Bank 1 Sensor 1 Circuit Description The heated oxygen sensor is used to determine the oxygen content of the engine s exhaust The oxygen content indicates when the engine is operating lean or rich When the engine is operating lean the exhaust will have more oxygen content Once at operating temperature the HO2S will produce a voltage in relation to the oxygen content of the exhaust The HO2S requires an operating temperature of 600 F 360 C to produce voltage The HO2S will produce more voltage when the exhaust is rich and less voltage when the exhaust is lean The HO2S operating range is around 0 10 volts 100 mV to 1 volt 1000 mV The PCM suppl
250. ual cause of the silica contamination is the use of unapproved silicon RTV engine gasket material or the use of silicon based sprays or fluids within the engine If the cause of this contamination is not corrected the replacement HO2S will also become contaminated 8 When testing the circuits for continuity the resistance should be less than 5 ohms When 2002 LPG G Van Service Manual Supplement Page 150 QUANTUM PROPANE FUEL SYSTEM testing the circuits for shorts the resistance HO2S that is exposed to the exhaust stream The should measure infinite with all components usual cause of the silica contamination is the use disconnected form the circuit of unapproved silicon RTV engine gasket 9 The step determines if a base engine concern is material or the use of silicon based sprays or causing the rich condition fluids within the engine If the cause of this 10 An HO2S contaminated by silicon will have a contamination is not corrected the replacement white powdery deposit on the portion of the HO2S will also become contaminated DTC P0172 DTC 56 Fuel Trim System Rich aer ion ei Yes Ne Did you perform the Alternative Fuels AF Powertrain Go to AF On Board Diagnostic OBD System Check Powertrain OBD System Go to Step 2 E Go to Step 3 Goto Step 4 Go to Step 14 ES Go to Step 14 Goto Step 5 2002 LPG G Van Service Manual Supplement Page 151 Connect the scan tool Capture the DTC information f
251. uels AF Powertrain On Board Diagnostic OBD System Check Using the scan tool establish communication with the AF ECM and clear DTC information Crank the engine Observe the DTC status Did the DTC reset Using the scan tool observe the AF ECM output driver data display with the engine cranking or running Does the AFO enable show a circuit fault Using the scan tool observe the AF ECM output driver data display with the engine cranking or running Does the low pressure lock off LPL show a circuit fault Does the fuel control solenoid FCS show a circuit fault Does the idle control solenoid ICS show a circuit fault Check the AF ECM to underhood LPL ground circuit for an open short to ground or short to power Refer to Engine Controls Schematics Was a problem found Website 9 2 03 Go to AF Powertrain OBD System Check Go to Intermittents Go to Step 4 Go to Step 7 Go to Step 5 mE Go to Step 8 Go to Step 6 Go to Go to Step 9 Intermittents Go to Step 16 Go to Step 11 2002 LPG G Van Service Manual Supplement Page 165 Check the AF ECM to FCS ground circuit for an open short to ground or short to power Refer to Engine Controls Schematics Was a problem found Check the AF ECM to ICS ground circuit for an open short to ground or short to power Refer to Engine Controls Schematics Was a problem found Check the AFO enable circuit from AF ECM to PCM for an ope
252. ult Not Present Fault Not Present indicates the condition that caused the DTC to set is intermittent and not currently present Refer to Intermittents in Symptom diagnosis for additional information If any additional DTCs were stored proceed to the applicable DTC table in the order stated in the AF OBD System Check Test Description The numbers below refer to the step numbers on the diagnostic table 5 This step indicates this sensor is currently functioning correctly If sent to this diagnostic procedure form other service information return to that procedure now 6 This step isolates the signal circuit from the other possible causes of the DTC condition 7 This step determines if the 5 volt reference circuit has the proper voltage The amperage available on the 5 volt reference circuit should be about 180 mA 8 This step determines if the signal circuit is shorted to voltage or open 9 This step determines if the sensor ground circuit has good continuity With the TP signal circuit jumpered to 5 volts and grounded through the sensor ground circuit terminal very little voltage should be available at the TP signal circuit DTC P0121 26 TP Sensor Circuit Performance Did you perform the Alternative Fuels AF Powertrain On Board Diagnostic OBD System Check Turn the ignition ON with the engine OFF Using the scan tool establish communication with the AF ECM Observe the TP sensor angle data parameter Doe
253. und and repair Go to Step 15 Go to Step 13 2002 LPG G Van Service Manual Supplement Page 110 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM on Y Vewes ves Ne Turn the ignition OFF Remove the jumper from the HO2S low circuit terminal Disconnect the PCM connector that contains the HO2S B1 S1 high signal circuit 20 mV Turn the ignition ON leaving the engine OFF Using a DVOM measure and record the voltage between the HO2S high signal circuit and ground Is the voltage measured greater than the value specified Go to Step 10 Go to Step 14 voltage Repair the HO2S signal circuit high circuit shorted to Go to Step 15 Go to Step 15 Go to Step 12 Go to Step 15 m Go to Step 15 i 2002 LPG G Van Service Manual Supplement Page 111 Is the action complete The HO2S may be detecting a rich exhaust condition Perform the AF Fuel System Diagnosis and return to this step Was a rich AF fuel system condition found and repaired Replace the AF ECM Refer to AF ECM Replacement Is the replacement complete Important The following PCM replacement procedures must be completed before attempting to operate the vehicle 1 Replace the PCM Refer to PCM Replacement in Engine Controls in the GM G VAN service manual Program flash the replacement PCM with the correct LPG software and calibration Is the replacement complete Replace the HO2S Refer to HO2S Replacement in Engine Con
254. ure the voltage on the 5 volt reference 5 2 volts circuit Is the voltage less that the specified value Go to Step 14 Go to Step 8 1 Inspect all 5 volt reference circuits for a short to voltage The 5 volt reference circuits A and B Go to Step 17 Goto Step 15 Go to Step 17 Goto Step 15 are shared with the PCM The short may be located on either of the 5 volt reference circuits that the PCM provides Go to Step 17 Go to Step 15 Disconnect the AF ECM connector that contains the 5 volt reference circuit to determine if the AF ECM is the cause of the short to voltage Repair the wiring as necessary Was a wiring repair made Inspect the sensor ground circuit for an open or high resistance condition between the MAP sensor connector and the PCM Inspect for proper terminal contact at the MAP sensor connector and the PCM Repair wiring or terminal contact as necessary Was a wiring or terminal repair made voltage Disconnect the AF ECM connector C002 to determine if the AF ECM is the cause of the short to voltage Repair the wiring as necessary Was a wiring repair made Turn the ignition OFF Disconnect the AF ECM connector that contains the MAP signal circuit With the MAP sensor connector disconnected test the MAP signal circuit for continuity Is MAP signal circuit continuity indicated Go to Step 13 Go to Step 12 Go to Step 17 KA 2002 LPG G Van Service Manual Supplement Page 67 Repair the ope
255. value specified Go to Step 6 Goto Step 11 Turn the ignition OFF Disconnect the AF ECM connectors Install a ground jumper wire to the underhood LPL at connector C008 Pin B Refer to Engine 78 mV Control Schematics Runthe engine until normal operating temperature is reached Using a scan tool monitor the HO2S B2 S1 voltage Is the HO2S voltage fixed less than the value specified Go to Step 7 Go to Step 12 2002 LPG G Van Service Manual Supplement Page 126 Website 9 2 03 QUANTUM PROPANE FUEL SYSTEM Stp Action Values Yes No Turn the ignition OFF Disconnect the HO2S B2 S1 connector Leave the AF ECM disconnected Jumper the HO2S low circuit terminal engine 351 to 551 harness side to a known good ground mV Turn the ignition ON while leaving the engine OFF Using a scan tool monitor the HO2S B2 S1 voltage Is the HO2S voltage within the value range specified Go to Step 8 Go to Step 9 The HO2S may be detecting a lean exhaust Go to Step 16 Go to Step 15 Go to Step 10 Go to Step 16 Ce Go to Step 16 Go to Step 13 2002 LPG G Van Service Manual Supplement Page 127 condition Inspect for one of the following conditions HO2S connector water intrusion Exhaust leak between the HO2S and the engine Vacuum leaks An inaccurate MAF sensor Repair any of the above or similar engine conditions as necessary Was a condition found and repair Repair the HO2S signal c
256. ve fuel lean the mixture when the HO2S indicates a rich exhaust This addition and removal to the air fuel mixture is indicated on the scan tool as the long and short term fuel trim values Short term fuel trim values are adjustments to the air fuel mixture that occur quickly Long term values are adjustments to the air fuel mixture that accumulate over longer periods of time The long and short term fuel trim values are displayed on a scan tool as both percent and counts A positive percentage value indicates fuel is being added to the mixture A Negative percentage value indicates fuel is being removed form the mixture This DTC is used to indicate a fully lean fuel trim system that cannot compensate for a rich engine exhaust content This DTC is a type B DTC Conditions for Running the DTC e The engine coolant temperature is greater than 185 F 85 C e The AF ECM is operating in closed loop fuel control Conditions for Setting the DTC The AF ECM monitors that the short term fuel trim is at 100 percent or long term fuel trim is at 50 percent for at least 5 seconds continuously Action Taken When the DTC Sets e A first failure of this DTC will NOT illuminate the MIL and will store as Last Test Failed but not as History Website 9 2 03 e The AF ECM will illuminate the MIL and store the DTC as History TWO consecutive drive trips that the diagnostic runs and fails e The AF ECM will record operating conditions at

2002 GM LPG Van Service Manual

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