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1. 54 V 6 Mid Temperature Switch circuit is always open V 8 Mid Temperature Switch circuit is always open 55 1 4 Road Load Vacuum Switch circuit is always open V 6 Mid Vacuum Switch circuit is always open V 8 Mid Vacuum Switch circuit is always open 1 6 Closed Throttle Vacuum Switch circuit is always open V 6 Hi Low Vacuum Switch circuit is always closed V 8 Hi Low Vacuum Switch circuit is always closed 62 Note High Altitude refers to vehicles with computer adjusted for operation at high elevations such as in Denver Colorado 1 4 car Idle Tracking Switch ITS circuit is closed at idle 1 4 truck Idle Decel Vacuum Switch circuit is always closed l 6 Wide Open Throttle WOT Vacuum Switch circuit is always closed V 6 All except High Altitude Altitude ALT circuit is open V 6 High Altitude only System pass V 8 All except High Altitude Altitude ALT circuit is open V 8 High Altitude only System pass 1 4 Wide Open Throttle WOT Vacuum Switch circuit is always closed l 6 CROWD Vacuum Switch circuit is always closed 65 Note High Altitude refers to vehicles with computer adjusted for operation at high elevations such as in Denver Colorado 1 4 All except High Altitude Altitude ALT circuit is open 1 4 High Altitude only System pass V 6 Mid Vacuum Switch circuit is always closed V 8 Mid Vacuum Switch circuit
2. Spark Advance Word SAW signal error or Spark Output SPOUT signal changed ignition timing to 10 BTDC Before Top Dead Center or Transaxle problem 1 2 shift error 51 Engine Coolant Temperature ECT sensor signal voltage is too high Power Steering Pressure Switch PSPS circuit is open or no changes detected 53 Throttle Position TP sensor signal voltage is too high as if indicating wide open throttle condition 54 Air Charge Temperature ACT sensor or Vane Air Temperature VAT sensor signal voltage is too high Open connection in Keypower circuit or electrical charging voltage too low 56 Mass Air Flow MAF sensor or Vane Air Flow VAF sensor voltage signal too high Or Electronic 4 Speed Overdrive Automatic Transaxle E40D Transmission Oil Temperature TOT sensor signal voltage is too high Neutral Pressure Switch NPS open circuit failure Or Circuit failed in Neutral position Or Octane adjust service pin installed 58 Vane Air Temperature VAT sensor signal voltage too high open connection in circuit or Crank fuel delay service pin in use circuit connected to ground or Idle Tracking Switch ITS circuit failure incorrect switch signal indications during Self Test 59 Transaxle problem failure in 4 3 pressure switch circuit open connection Or Low speed fuel pump circuit
3. 625 Electronic Pressure Control EPC solenoid circuit driver problem in Electronic Control Assembly ECA 626 Coast Clutch Solenoid CCS circuit failure 627 Converter Clutch Solenoid CCC circuit failure 8 62 Excessive converter clutch slippage 629 Converter Clutch Solenoid CCC Converter Clutch Override CCO solenoid Lock Up Solenoid LUS or MLUS circuit failure 631 Overdrive Cancel Indicator Light OCIL circuit failure 632 Overdrive Cancel Switch OCS no switch action detected during Engine Run Self Test 633 4x4L switch closed during Key On Engine Off Self Test 634 Manual Lever Position MLP sensor signal voltage higher or lower than expected 635 Transmission Temperature Switch TTS open circuit failure 636 Transmission Oil Temperature TOT sensor signal voltage higher or lower than expected 637 Transmission Oil Temperature TOT sensor signal voltage too high 638 Transmission Oil Temperature TOT sensor signal voltage too low Turbine Speed Sensor TSS insufficient signal level 30 641 Shift Solenoid 3 SS3 circuit failure 643 Shift Solenoid 4 SS4 circuit failure 645 Transmission problem incorrect gear ratio obtained for first gear 646 Transmission problem incorrect gear ratio obtained for second gear 647 Transmission problem in
4. Hertz Hz A term for frequency cycles per second IAC Intake Air Control Ignition Diagnostic Monitor A wire between the ECA and the switched side Tach terminal of the ignition coil The ECA uses this circuit to check for the presence of ignition pulses Inputs Electrical signals running into the ECA These signals come from sensors switches or other electronic modules They give the ECA information about vehicle operation Integrated Relay Control Module IRCM A single module containing several relays and some other circuitry The ECA uses these relays for control of functions such as fuel pump air conditioner clutch electric cooling fan and EEC IV system power ISC Idle Speed Control This refers to a small electric stepper motor mounted on the throttle body and controlled by the ECA See Stepper Motor definition The ISC motor moves a spindle back and forth When the throttle is released during idle it rests on this spindle The ECA can control idle speed by adjusting this spindle position The ECA determines the desired idle speed by looking at coolant temperature engine load and RPM The Idle Tracking Switch see ITS definition is built into the tip of the spindle The ISC motor also performs dashpot and anti dieseling functions ISC BPA Idle Speed Control By Pass Air valve This is a solenoid type actuator mounted on the throttle body and controlled by the ECA with a dut
5. 41 All Engines Exhaust Gas Oxygen EGO sensor voltage signal always lean low value does not switch All Engines Exhaust Gas Oxygen EGO sensor voltage signal always rich high value does not switch 44 All Engines Exhaust Gas Oxygen EGO sensor signal voltage indicates rich high value with Thermactor air switched upstream to the exhaust manifold a lean air fuel condition All Engines Thermactor air flow is always upstream going to exhaust 49 manifold All Engines Thermactor Air System unable to bypass air vent to atmosphere 1 4 Low or Mid Temperature Switch circuit is open when engine is hot l 6 Low Temperature Vacuum Switch circuit is open when engine is hot V 6 Hi or Hi Low Vacuum Switch circuit is always open V 8 Hi or Hi Low Vacuum Switch circuit is always open 52 l 4 car Idle Tracking Switch ITS voltage does not change from closed to open throttle Closed throttle checked during Key On Engine Off condition Open throttle checked during Engine Running conditions l 4 truck Idle Decel Vacuum Switch circuit always open l 6 Wide Open Throttle WOT Vacuum Switch circuit is always open 1 4 Wide Open Throttle WOT Vacuum Switch circuit is always open l 6 CROWD Vacuum Switch circuit is always open V 6 Dual Temperature Switch circuit is always open V 8 Dual Temperature Switch circuit is always open
6. 1 Verify e Ignition Key is in OFF Position e Code Scanner is Connected e HOLD TEST Switch is in TEST Position WARNING The next step involves starting the engine Observe safety precautions e Always operate vehicle in a well ventilated area Do NOT inhale exhaust gases they are very poisonous e Set the parking brake e Put shift lever in PARK automatic transmission or NEUTRAL manual transmission 46 e Block the drive wheels e Stay away from moving engine parts 2 Start the Engine 3 Warm Up Engine e Allow engine to idle until it reaches normal operating temperature Then e Run engine at 2000 RPM for 2 minutes 4 Turn Engine Off Then Immediately Restart Engine and Allow to Idle Note Vehicles with Throttle Kicker actuator the Throttle Kicker will extend increasing RPM and remain so throughout the test 5 Get Engine Identification ID Code from the Flashing STO Light e An engine ID code is sent after a few seconds to signal the beginning of KOER Self Test e Count flashes on the STO light Ignore any flashes lasting longer than 1 second 6 cylinder 3 Flashes 8 cylinder 4 Flashes Note If the light does not flash or flashes the wrong number go back and repeat SELF TEST PART 3 starting with Step 1 If the light still does not flash correctly you have a problem which must be repaired before proceeding Refer to the vehicle service manual
7. 2 Also called TAD solenoid See TAD definition AXOD Automatic Transaxle with Overdrive gear BOO Brake On Off switch signal Tells the ECA when the brakes are being applied BP Barometric Pressure sensor See MAP definition CANP Canister Purge solenoid This device controls the flow of fuel vapors from the canister to the intake manifold The canister collects vapors evaporating from the fuel tank preventing them from escaping into the atmosphere During warm engine cruise conditions the ECA energizes CANP so the trapped vapors are drawn into the engine and burned ccc Converter Clutch solenoid Located in certain electronically controlled transmissions The ECA uses this solenoid to control the lock up clutch in the torque converter The ECA will engage or release lock up depending upon engine operation CCS Coast Clutch Solenoid Located in certain electronically controlled transmissions The ECA uses this solenoid to permit engine braking during deceleration when in third gear with gear shift lever in Drive cco Converter Clutch Override solenoid Located inside transmission having mechanically controlled lock up torque converter The ECA uses this solenoid to disable lock up under certain engine operating conditions CFI Central Fuel Injection A fuel injection system having one or two injectors mounted in a centrally located throttle body as opposed to position
8. High speed fuel pump relay circuit failure 97 Right side Exhaust Gas Oxygen EGO sensor signal voltage indicates rich during lean air fuel conditions or Overdrive Cancel Indicator Light OCIL circuit failure 98 A system problem is present causing the Electronic Control Assembly ECA to operate in Failure Management and Effects Mode FMEM or Right side Exhaust Gas Oxygen EGO sensor signal voltage indicates lean during rich air fuel conditions or Electronic Pressure Control EPC solenoid circuit failure 99 The Electronic Control Assembly ECA has not learned to control engine idle speed ignore code 12 or 13 or Electronic Pressure Control EPC solenoid circuit failure Three Digit Codes Certain 1991 and newer vehicles use 3 digit codes to report the results of the system Self Test procedure Refer to your vehicle service manual to determine if your system uses 2 or 3 digit codes e Code meanings can vary with vehicle model year engine type options and type of test being performed e Many of the codes listed may not apply to your vehicle e Follow vehicle service manual procedures to find the cause of the code Always start with the first code displayed Remember 1 Visual inspections are important 2 Problems with wiring and connectors are common especially for intermittent faults 3 Mechanical problems
9. Identifying the problem is the first step in solving that problem Your Actron Code Scanner can help you determine by accessing the engine computer trouble codes Armed with that knowledge you can either refer to an appropriate service manual or discuss your problem with a knowledgeable service technician In either event you can save yourself a lot of valuable time and money in auto repair And feel confident that your vehicle s problem has been fixed Actron offers a compete line of high quality automotive diagnostic and repair equipment See your local Actron dealer for other Actron products CONTENTS 1 About Codes Where do they come from and what are they for 3 2 Code Scanner Basics When do you use it and what does it do 5 3 Connector Location Connector type identifies the computer system in your vehicle EEC IV or MCU 7 4 Using the Code Scanner EEC IV system Complete description for reading and using service codes 8 5 Code Meanings EEC IV system Service Code Definitions for Ford EEC IV engines cccceeeeeeeeees 20 6 Other Features EEC IV system Additional Code Scanner Diagnostic O E eR EEES 31 7 Using the Code Scanner MCU system Includes engine off and engine running tests cccccc 37 8 Code Meanings MCU system Service Code Definitions for Ford MCU engines ooooncccnnnccnnnnncnnnncinns 47 9 Computer Basics What does the eng
10. Key On Engine Running KOER Self Test IMPORTANT You must complete all steps in Self Test Parts 1 2 and 3 before proceeding to Part 4 Verify good battery in Code Scanner Section 2 1 Verify Ignition Key is in OFF Position 2 Put Code Scanner HOLD TEST Switch in HOLD Position WARNING The next step involves starting the engine Observe safety precautions e Always operate vehicle in a well ventilated area Do NOT inhale exhaust gases they are very poisonous e Set the parking brake e Put shift lever in PARK automatic transmission or NEUTRAL manual transmission e Block the drive wheels e Stay away from moving engine parts 3 Start the Engine e If engine will not start stalls or runs rough refer to vehicle service manual for troubleshooting charts related to the symptom 4 Run the Engine to Warm the EGO Sensor e The EGO Exhaust Gas Oxygen sensor must be warmed up to operate for this test e Run engine at 2000 RPM for at least 2 minutes 5 Turn Engine OFF Wait 10 Seconds Restart Engine 6 Put Code Scanner HOLD TEST Switch in TEST Position e This starts the KOER Key On Engine Running Self Test 7 Get Engine Identification ID Code from the Flashing STO Light NOTE If the light does not flash go back and repeat SELF TEST PART 4 starting with Step 5 If the light still does not flash you have a problem which must be repaired before proceeding Refer
11. Thus the computer can get a vacuum controlled actuator to move half way between no vacuum position and full vacuum position Other positions can be achieved by changing the duty cycle of the control signal which in turn changes the average amount of control vacuum 58 DVM Digital Volt Meter An instru ment using a numeric read out to display measured voltage values as opposed to a moving needle on a gauge face Usually the instrument has other mea suring capabilities such as resistance and current and may be called a DMM Digital Multi Meter Most DVM s have 10 Megohm input impedance This means the circuit under test will not be electronically disturbed when the DVM is connected for a measurement Dynamic Response A user action expected by the ECA during the course of a diagnostic Self Test Normally this means performing a brief wide open throttle action during the Engine Running Self Test The ECA sends a single voltage pulse through the STO circuit making a blink on the Code Scanner LED signaling the user to perform the Dynamic Response action ECA Electronic Control Assembly The brains of the engine control system It is a computer housed ina metal box with a number of sensors and actuators connected with a wiring harness Its job is to control fuel delivery idle speed spark advance timing and emission systems The ECA receives information from sensors then energize
12. beeps when the codes are sent 3 Turn Ignition Key to ON Position but DO NOT START THE ENGINE e This starts the KOEO Self Test e Codes are sent after 5 seconds e Pay no attention to a brief blink which may occur after ignition key is turned to ON position 4 Get Codes from the Flashing STO Light Note If the light does not flash go back and repeat SELF TEST PART 2 starting with Step 1 If the light still does not flash you have a problem which must be repaired before proceeding Refer to the vehicle service manual Self Test Not Functional or similar title trouble shooting chart e Count flashes to get service codes Each flash lasts 1 2 second Code 12 looks like al ty Av PAUSE ATA FLASH pause FLASH FLASH FLASH 1 FLASH FLASH 2 Put 1 and 2 together code 12 Code 23 looks like FLASH FLASH pause FLASH FLASH FLASH e All codes are 2 digits long e The pause between each digit is 2 seconds e After all codes are sent the whole group is sent again just one more time so you can double check your code list e The longer pause between each code is 4 seconds Example of code 12 only Ny NUN Av PAUSE TAS FLASH pause FLASH FLASH longer pause NZ NUN Av PAUSE AT FLASH pause FLASH FLASH Example of code series 12 and 42 NZ NUN Av PAUSE WON FLASH pause FLASH FLASH longer pause FLASH FLASH pause LASH FLASH longer pa
13. sends a frequency signal to the ECA The frequency increases as the vehicle moves faster to give the ECA vehicle speed information VVC Voltage Variable Choke actuator Used on feedback carburetors in MCU systems The MCU module sends a duty cycle type signal to this actuator in order to control the amount of choke opening See Duty Cycle definition WAC Wide open throttle Air conditioner Cut off relay Used by the ECA to turn off the A C clutch and thus reduce engine loading This is desirable during heavy acceleration engine cranking or engine overheating conditions WOT Wide Open Throttle The vehicle operating condition brought about when the throttle is completely or nearly so open The ECA typically delivers extra fuel to the engine at this time for acceleration purposes The ECA uses the Throttle Position sensor to identify the WOT condition WOT Vacuum Switch Wide Open Throttle Vacuum Switch Used on MCU systems The switch is closed when applied vacuum is weak and open when vacuum is strong The MCU module detects WOT operation when the weak manifold vacuum present during WOT conditions causes the vacuum switch to close The MCU module provides extra fuel at this time for acceleration purposes Zone Vacuum Switches Used in some Microprocessor Control Unit MCU systems These three switches are used to detect low medium and high vacuum levels in the intake manifold They sen
14. vacuum leaks binding or sticking linkages etc can make a good sensor look bad to the computer 4 Incorrect information from a sensor may cause the computer to control the engine in the wrong way Faulty engine operation might even make the computer show a different good sensor as being bad 111 System pass Air Charge Temperature ACT sensor signal voltage is too low 26 113 Air Charge Temperature ACT sensor signal voltage is too high 114 Air Charge Temperature ACT sensor signal voltage is higher or lower than expected 116 Engine Coolant Temperature ECT sensor signal voltage is higher or lower than expected 117 Engine Coolant Temperature ECT sensor signal voltage is too low Engine Coolant Temperature ECT sensor signal voltage is too high Throttle Position TP sensor signal voltage is higher or lower than expected Or Throttle Position TP sensor signal voltage inconsistent with engine intake air flow 122 Throttle Position TP sensor signal voltage is too low 123 Throttle Position TP sensor signal voltage is too high 124 Throttle Position TP sensor signal voltage is higher than expected 125 Throttle Position TP sensor signal voltage is lower than expected 126 Manifold Absolute Pressure MAP or Barometric Pressure BP signal values higher or lower than expected 128 Man
15. Self Test Not Functional or similar title troubleshooting chart 6 Test Knock Sensor if used on vehicle If vehicle does not use knock sensor skip this step and go to Step 7 e Do the following immediately after engine ID code is sent Simulate spark knock by placing a 3 8 inch socket extension or similar tool on manifold near base of knock sensor OZ hammer for 15 seconds DO NOT TAP SENSOR 7 Get Service Codes From the Flashing STO Light e Count flashes on the STO light This is done the same way as in Self Test Part 2 Ignore any flashes lasting longer than 1 second Code 12 looks like sl xl 1 Seb PAUSE 303 FLASH pause FLASH FLASH FLASH 1 FLASH FLASH 2 Put 1 and 2 together code 12 e All codes are 2 digits long e After all codes are sent the whole group is sent again just one more time so you can double check your code list Example of code series 12 and 42 NZ NUN Av PAUSE TAS FLASH pause FLASH FLASH longer pause FLASH FLASH pause LASH FLASH longer pause FLASH FLAS F NZ NUN Av PAUSE TAS FLASH pause FLASH FLASH longer pause LASH FLASH pause LASH FLASH 8 Turn Ignition Key to OFF Position 9 Remove Code Scanner At this point you can either e Have your vehicle professionally serviced Codes indicate problems found by the computer or e Repair the vehicle yourself using servi
16. Spark Retard Solenoid to bleed control vacuum from the distributor advance to retard the ignition timing MCU Controlled Emission Systems e Thermactor Air System All MCU vehicles have this system which is similar to the one discussed earlier in this section The MCU uses engine temperature throttle position information to determine proper operation of the thermactor system e Fuel Evaporation Recovery System This system is similar to the one discussed earlier in this section It is only used on some MCU vehicles The MCU uses engine temperature and throttle position information to determine proper operation of this system REFERENCE GLOSSARY A C Air conditioner ACC Air Conditioner Clutch signal This tells the ECA that either the A C compressor is running or that A C operation is being requested depends upon vehicle ACT Air Charge Temperature sensor This sensor is a thermistor a resistor whose resistance decreases with temperature It is threaded into the intake manifold so the ECA can determine the temperature of the incoming air This is used for fuel delivery calculations Actuator Devices which are powered by the ECA to control things Actuator types include relays solenoids and motors Actuators allow the ECA to control engine operation A F Air fuel AM 1 Air Management solenoid 1 Also called TAB solenoid See TAB for explanation AM 2 Air Management solenoid
17. be a system pass code 11 or 111 if no problems were seen The KOEO code group is sent twice So you can double check your code list The second code group has Continuous Memory codes for problems which occurred in the past and have been memorized by the computer These problems sometimes called intermittences may or may not be present now The Continuous Memory group will always contain at least one code This will be a system pass code 11 or 111 if no problems were seen The Continuous Memory code group is sent twice so you can double check your code list e Code sequence example with KOEO codes 21 and 32 Continuous Memory code 14 NEN y JCC PAUSE X FLASH FLASH pause FLASH longer pause FLAS I FLASH FLASH a FLASH FLASH longer pause sl gt 9070 PAUSE w FLASH FLASH pause FLASH longer pause FLAS I LASH FLASH a FLASH FLASH very long pause So SEPARATOR CODE FLASH separator code very long pause FLASH pause FLASH FLASH FLASH FLASH longer pause FLASH FLASH FLASH FLASH e Write down codes in the order they are sent 6 Turn Ignition Key to OFF Position At this point you can either e Have your vehicle professionally serviced Codes indicate problems found by the computer or e Repair the vehicle yourself using service codes to help pinpoint the problem Refer to Test Resu
18. computer controls this solenoid to vary air flow Hot engine cruise condition Closed Loop operation The computer uses the engine temperature and throttle position information to tell when the engine is all warmed up and cruising At this time the computer will use the Exhaust Gas Oxygen sensor to run the engine ina closed loop mode for minimum emissions and best fuel economy Cold start Acceleration Deceleration and Idle Open Loop operation The computer runs the engine in an open loop mode when sensor information signals one of the driving conditions listed above The computer relies on factory programmed instruc tions to determine the proper air fuel mixture to deliver MCU idle speed adjustment The MCU system does not control idle speed a standard mechanical idle cam mechanism is used However some MCU systems have a vacuum operated Throttle Kicker actuator The computer uses this device to push the throttle linkage off idle position when additional idle RPM is required This happens when sensors indicate a cold start or engine overheat condition The computer energizes a Throttle Kicker Solenoid to apply vacuum to the actuator MCU spark retard The MCU system does not control spark timing a standard distributor is used However some MCU systems can send a signal to retard timing if the knock sensor indicates an engine knock condition The computer energizes a
19. converter overheat or during very cold engine starting Air goes into the exhaust manifold during normal engine warm up This helps burn hot unused fuel vapors in the exhaust stream reduces pollutants speeds exhaust warm up The TAB and TAD valves may be separate units or combined into one assembly Thermistor A resistor whose resistance changes with temperature Thermistors are used as sensors for vehicle coolant and manifold air temperature The resistance decreases as temperature goes up THS 3 2 and THS 4 3 Transmission Hydraulic Switch These are pressure switches used in some automatic transaxles They send gear information to the ECA as follows THS 3 2 only signal means 2nd gear Both THS 3 2 and THS 4 3 signals means 3rd gear THS 4 3 only signal means 4th gear TK Throttle Kicker solenoid The ECA uses this solenoid to apply vacuum and thus activate the throttle kicker actuator The actuator increases the amount of idle position throttle opening by a fixed amount The ECA activates TK when operating conditions require faster idle such as when the A C compressor is on or during cold engine Start up TOT Transmission Oil Temperature sensor This sensor is a thermistor a resistor whose resistance decreases with temp erature It lies within the transmission housing in contact with the oil The ECA uses this sensor to monitor transmission operating temperature Thro
20. corrosion Do Inspect the air cleaner and ductwork not wipe off Obtain extra grease if needed from your vehicle dealer It is a special type for this purpose Repair any problems found during the visual inspection and retest the vehicle If the original symptom is still present continue the test Go to Step 3 Prepare Vehicle 3 Prepare Vehicle e Turn off all electrical equipment and accessories in vehicle e Keep all vehicle doors closed during testing e Make sure radiator coolant and transmission fluid are at proper levels e If the air cleaner must be removed for example to measure the choke voltage leave all vacuum hoses attached to the air cleaner housing e Start the engine and allow it to idle If the engine does not start refer to the No Start diagnostic procedure in the vehicle service manual WARNING Always operate vehicle in a well ventilated area Do NOT inhale exhaust gases they are very poisonous Stay away from moving parts e Check for power at the choke while the engine is running Use a voltmeter to measure the voltage between the choke cap terminal and engine ground Battery Powered Choke voltage should be about 12 volts Alternator Powered Choke voltage should be about 7 5 volts If any problems are found in the choke power circuit make necessary repairs and re do the Self Test process starting with Step 1 Continue this procedure if no prob
21. failure or Electro Drive Fan circuit failure or Intake Air Control IAC valve circuit failure Or Boost solenoid circuit failure 82 Thermactor Air Bypass TAB or AM 1 solenoid circuit failure Or Electro Drive Fan circuit failure Or Supercharger Bypass Solenoid SBS circuit failure 83 High Speed Electro Drive Fan HEDF circuit failure Or EGR Control EGR C solenoid open circuit failure Or Low speed fuel pump relay open circuit failure EGR Vacuum EGR V solenoid circuit failure Or EGR Vacuum Regulator EVR solenoid circuit failure Or EGR Shut Off EGR S O solenoid circuit failure 85 Cannister Purge CANP solenoid circuit failure Or Transaxle problem 3 4 shift solenoid circuit failure Or Electronic Control Assembly ECA status adaptive lean limit reached in fuel control program Transaxle problem 3 4 shift solenoid circuit failure Or Electronic Control Assembly ECA status adaptive rich limit reached in fuel control program Or Wide open throttle Air conditioner Clutch WAC solenoid circuit failure 87 Fuel Pump FP relay circuit failure 88 Electro Drive Fan EDF relay circuit failure Or Converter Clutch Override CCO solenoid circuit failure Or Distributorless Ignition System DIS problems loss of dual plug control or Thro
22. low circuit failure 811 Fuel injector Pump Lever FIPL signal voltage higher or lower than expected 812 Fuel Injector Pump Lever FIPL signal voltage too high 813 Fuel Injector Pump Lever FIPL signal voltage too low 998 Engine control system operating in Failure Mode and Effects Management FMEM programming strategy 31 32 OTHER FEATURES Additional Code Scanner Diagnostic Features Part 1 Relay and Solenoid Test Service manuals call this the Output State Check You can turn on most of the computer controlled relays and solenoids except the fuel pump relay and fuel injectors This is helpful for checking voltages relay operation etc The output state check is automatically activated at the end of the normal Key On Engine Off Self Test procedure explained in Section 4 Do the following 1 Safety First e Set the parking brake e Put shift lever in PARK automatic transmission or NEUTRAL manual transmission e Block the drive wheels 2 Make Sure Ignition Key is in OFF Position 3 Check Code Scanner Battery e Refer to Section 2 4 Connect Code Scanner e Refer to Section 3 e Plug BOTH test connectors into the Code Scanner 6 Turn Ignition 7 Put Hold Test 5 Put Hold Test Switch in HOLD Position Key to ON Position but DO NOT START ENGINE AUDIO Switch in TEST STO Su er Sunpro 4 Position CODEC F os
23. minimum learning limit reached 416 Idle Speed Control system maximum learning limit reached 452 Vehicle Speed Sensor VSS signal too small 461 RPM or Vehicle Speed Sensor VSS limit reached NO REPAIR REQUIRED 511 Electronic Control Assembly ECA problem Read Only Memory ROM test failure 512 Electronic Control Assembly ECA problem Keep Alive Memory test failure 513 Electronic Control Assembly ECA problem internal voltage test failure 519 Power Steering Pressure Switch PSPS open connection circuit failure 521 Power Steering Pressure Switch PSPS circuit switching not detected 522 Vehicle transmission not in PARK during Key On Engine Off Self Test 524 Low Speed Fuel Pump open circuit failure between battery and Electronic Control Assembly ECA 525 Vehicle transmission in gear or air conditioner on 527 Neutral Position Switch NPS open circuit failure or Air Conditioner on during Engine Off Self Test 528 Clutch Switch CS circuit failure 529 Data Communication Link DCL or Electronic Engine Control EEC system circuit failure 532 Cluster Control Assembly CCA circuit failure 533 Electronic Instrument Cluster EIC circuit failure in Data Communication Link DCL 536 Brake On Off BOO switch circuit failure or not activated during Engine Run Self Test 538 Insuffic
24. much fuel to deliver and operate the fuel injectors accordingly Engines with feedback carburetors don t do any of this They use a Variable Voltage Choke The computer controls the amount of choke opening This is an example of Open Loop operation by the computer The control system performs an action expecting a certain result but has no way of verifying if the desired results were achieved In this case the computer pulses a fuel injector expecting a certain amount of fuel to be delivered The computer assumes everything in the fuel system is operating as expected In open loop operation the computer has no way of checking the actual amount of fuel delivered Thus a faulty injector or incorrect fuel pressure can change the amount of fuel delivered and the computer would not know it Hot engine cruise condition Closed Loop operation The computer watches the coolant temperature and throttle position sensors to tell when the engine is all warmed up and cruising As before the computer determines the amount of air coming into the engine then delivers the amount of fuel that should provide the optimum air fuel mixture The big difference is that this time the computer uses the oxygen sensor to check how well it s doing and readjust things if needed to make sure the fuel delivery is correct This is an example of Closed Loop operation The control system performs an action expecting a cert
25. primary side circuit failure Ignition system distributor less problem Loss of left side Ignition Diagnostic Monitor IDM signal 19 Ignition system problem Spark Output SPOUT signal open circuit no spark advance timing 221 Distributorless Ignition System DIS problem Spark timing error Distributorless Ignition System DIS problem Loss of right side Ignition Diagnostic Monitor IDM signal 223 Distributorless Ignition System DIS problem Loss of Dual Plug Inhibit DPI control 224 Distributorless Ignition System DIS problem Primary circuit failure in Coil 1 2 3 or 4 225 Knock Sensor KS signal not detected during Dynamic Response Test Engine Run Self Test 226 Electronic Distributorless Ignition System EDIS problem Ignition Diagnostic Monitor IDM signal not received 227 Electronic Distributorless Ignition System EDIS problem Crankshaft Position Sensor CPS error 232 Electronic Distributorless Ignition System EDIS problem Coil 1 2 3 or 4 circuit failure 233 Electronic Distributorless Ignition System EDIS problem Spark Advance Word SAW signal error 238 Ignition system distributorless problem Coil 4 primary side circuit failure 239 Electronic Distributorless Ignition System EDIS problem Crankshaft Position Sensor CPS signal received with engine off 241 Ignition Diagno
26. the cap from the anti backfire vacuum switch tee during testing The switch is located behind the MCU module Be sure to replace the cap after testing and servicing is complete 2 3L engines with an EGR vacuum load control wide open throttle valve Cover the atmospheric vent holes with a piece of tape Be sure to remove the tape after testing and servicing is completed 4 2L and 5 8L engines with a vacuum delay valve There is a tee with a restrictor in the Thermactor Vacuum control line The restrictor must be uncapped during the test Replace the cap after testing Refer to drawing for location of restrictor on the TAD vacuum line 4 2L engines or the TAB vacuum line 5 8L engines TEE amp VACUUM 5 8L ONLY RESTRICTOR TO SOURCE TAB soL Vacuum VACUUM DELAY VALVE EXHAUST MAN UPSTREAM OR de CATALYST lt E o VACUUM DOWNSTREAM DELAY VALVE TO SOURCE VACUUM EXHAUST MAN UPSTREAM OR CATALYST DOWNSTREAM 6 Have a Pencil and Paper Ready e This is for writing down all the codes 7 Go to SELF TEST PART 2 Key On Engine Off KOEO Self Test 42 Self Test Part 2 Key On Engine Off KOEO Self Test IMPORTANT You must complete all steps in Self Test Part 1 before proceeding to Part 2 1 Verify Ignition Key is in OFF Position and Code Scanner is Connected 2 Put Code Scanner HOLD TEST Switch in TEST Position e Optional Turn the AUDIO switch ON to hear
27. 6 amp Older Wiggle Test is now activated Go to Step 9 e 1987 amp Newer Without pausing move HOLD TEST switch to TEST then to HOLD and then back to TEST Wiggle Test is now activated Go to Step 9 9 Perform Wiggle Test on Suspected Circuit e Lightly tap sensor e Wiggle sensor connector e Twist and shake wiring between sensor and computer e If the above actions recreate an intermittent fault the STO light will light and a tone will sound for as long as the fault is present This can help locate the area of an intermittent problem NOTE If a fault is recreated this way a service code will be stored in computer memory Be sure to erase this code from memory after making all repairs Refer to Section 4 Self Test Part 5 Erasing Continuous Memory codes 10 Move Switches e HOLD TEST switch to HOLD e AUDIO switch to OFF 11 Turn Ignition Key to Off Position 12 Disconnect Code Scanner 37 Circuits Checked by Continuous Monitor 1984 amp up 1984 amp up 1984 amp up 1990 amp up 1984 amp up 1990 amp up DIS or dual plug DIS only 1990 amp up 1990 amp up 1984 amp up 1986 amp up 1984 amp up 1985 amp up 1984 amp up 38 MCU SYSTEM Using the Code Scanner MCU Systems Complete Description for Reading and Using Service Codes Do This First This section shows you how to use the Code Scanner for e Runnin
28. Flashes 6 cylinder 3 Flashes Note If the light does not flash or flashes the wrong number go back and repeat SELF TEST PART 3 starting with Step 1 If the light still does not flash correctly you have a problem which must be repaired before proceeding Refer to the vehicle service manual Self Test Not Functional or similar title trouble shooting chart 5 Get Service Codes From the Flashing STO Light e Maintain engine speed at 3000 RPM until codes are sent then release throttle and return to idle RPM e Count flashes on the STO light This is done the same way as in Self Test Part 2 Ignore any flashes lasting longer than 1 second Code 12 looks like Seb PAUSE Sto 386 FLASH pause FLASH FLASH FLASH 1 FLASH FLASH 2 Put 1 and 2 together code 12 e All codes are 2 digits long e After all codes are sent the whole series is sent again just one more time so you can double check your code list Example of code series 12 and 42 Y gt y 38 PAUSE 30658 FLASH pause FLASH longer pause FLASH NZ y PAUSE gt de Se 2 N 1 H FLASH FLASH pause LASH FLASH FLAS F longer pause 1 o yy Je PAUSE 30658 FLASH pause FLASH longer pause FLASH FLASH FLASH aes ASH FLASH 6 Turn Ignition Key to OFF Position 7 Remove Code Scanner For Vehicles With V 6 amp V 8 Engines Refer to page 43 for l 4 and l 6 engines
29. GR sensor The ECA uses this sensor to determine the amount EGR flow The task is involved In this EGR system a small opening separates the exhaust manifold from the EGR valve input All the gases flowing through the EGR valve must first pass through this opening Scientific principles allow the ECA to calculate EGR flow providing it can determine the pressure on both sides of this opening that is both the EGR valve input side and the manifold side The PFE sensor measures the pressure seen at the EGR side The sensor sends a voltage signal which increases as pressure is increased The manifold side pressure must be calculated by the ECA based on RPM exhaust system characteristics and other information The ECA can then finally calculate EGR flow Note that with this system the PFE signal is NOT a direct measure of EGR flow PIP Profile Ignition Pick Up signal It is a frequency type providing crankshaft position and speed information The ECA uses PIP as a reference to create properly timed ignition system and fuel injector signals The PIP signal comes from a sensor mounted in the distributor TFI IV ignitions or from a separate crankshaft mounted sensor Crankshaft Position Sensor used on distributorless ignitions 62 PSPS Power Steering Pressure Switch This tells the ECA when power steering is being used The ECA can prevent stalling on a small idling engine by watching this switch and increas
30. ION OF INCIDENTAL OR CON SEQUENTIAL DAMAGES SO THIS LIMITATION OR EXCLUSION MAY NOT APPLY TOA SPECIFIC BUYER THIS WARRANTY GIVES YOU SPECIFIC LEGAL RIGHTS AND YOU MAY ALSO HAVE OTHER RIGHTS WHICH VARY FROM STATE TO STATE TO USE YOUR WARRANTY If you need to return the unit please follow this procedure 1 Call Actron Tech Support at 800 253 9880 Our Technical Service representatives are trained to assist you 2 Proof of purchase is required for all warranty claims Please retain your sales receipt 3 In the event that product needs to be returned you will be given a Return Material Authorization number 4 If possible return the product in its original package with cables and accessories 5 Print the RMA number and your return address on the outside of the package and send to the address provided by your Customer Service representative 6 You will be responsible for shipping charges in the event that your repair is not covered by warranty OUT OF WARRANTY REPAIR If you need product repair after your warranty has expired please call Tech Support at 800 253 9880 You will be advised of the cost of repair and any freight charges All information illustrations and specifications contained in this manual are based on the latest information available from industry sources at the time of publication No warranty expressed or implied can be made for its accuracy or completeness nor is any responsibility assumed by Actron or anyon
31. Self Test Not Functional or similar title troubleshooting chart Note High Altitude refers to vehicles with computer adjusted for operation at high elevations such as in Denver Colorado 44 Self Test Part 3 Key On Engine Running KOER Self Test IMPORTANT You must complete all steps in Self Test Parts 1 and 2 before proceeding to Part 3 For Vehicles With 1 4 amp l 6 Engines Refer to page 44 for V 6 amp V 8 engines 1 Verify e Ignition Key is in OFF Position e Code Scanner is Connected e HOLD TEST Switch is in TEST Position WARNING The next step involves starting the engine Observe safety precautions e Always operate vehicle in a well ventilated area Do NOT inhale exhaust gases they are very poisonous e Set the parking brake e Put shift lever in PARK automatic transmission or NEUTRAL manual transmission e Block the drive wheels e Stay away from moving engine parts 2 Start the Engine 3 Increase and Hold Engine Speed at 3000 RPM Within 20 Seconds of Start e Maintain engine speed at 3000 RPM until service codes are sent end of Step 5 4 Get Engine Identification ID Code from the Flashing STO Light e Maintain engine speed at 3000 RPM e An engine ID code is sent after a few seconds to signal the beginning of KOER Self Test e Count flashes on the STO light Ignore any flashes lasting longer than 1 second 4 cylinder 2
32. T signal voltage lower than expected 327 EGR Valve Position EVP sensor Pressure Feedback EGR PFE sensor or EGR Pressure Transducer EPT signal voltage too low EGR Valve Position EVP sensor signal voltage lower than expected closed valve position 332 Insufficient EGR flow detected 334 EGR Valve Position EVP sensor signal voltage higher than expected closed valve position Pressure Feedback EGR PFE sensor or EGR Pressure Transducer EPT signal voltage higher or lower than expected Key On Engine Off Self Test 336 Pressure Feedback EGR PFE sensor or EGR Pressure Transducer EPT signal voltage higher than expected exhaust pressure high 337 EGR Valve Position EVP sensor Pressure Feedback EGR PFE sensor or EGR Pressure Transducer EPT signal voltage too high Engine Coolant Temperature ECT sensor signal voltage lower than expected 339 Engine Coolant Temperature ECT sensor signal voltage higher than expected 341 Octane Adjust service pin in use 381 Air Conditioner A C clutch is cycling frequently Cannot control RPM during Engine Run Self Test low RPM check 412 Cannot control RPM during Engine Run Self Test high RPM check 413 Idle Speed Control actuator operating at minimum limit 414 Idle Speed Control actuator operating at maximum limit 415 Idle Speed Control system
33. a3actron precision electronic solutions 2 CODE SCANNER FAVOR DE LEER INSTRUCTCTIVO ANTES DE USAR EL ARTICULO Car Computer Code Reader Domestic Ford Lincoln Mercury with EEC IV or mae En MCU Engine Computer EN OS us Control Systems l pps CODE LN de Computadoras i de Autom vil CP9015 Lincoln amp Moray Ford Lincoln Mercury N nacionales de EE UU con N Systemas MCU y EEC IV para EUA Instrucci nes en espa ol p gina 67 Lector de C digos Lecteur de code d ordinateur automobile m Ford Lincoln Mercury domestiques Etas Unis avec Syst mes MCU ou EEC IV Instructions en fran ais page 133 Tensi n 16V Para Nombre Domicilio y Telefono Hecho en China Ge Importador Ver Empaque CP901 5 elactron CP9015 CODE SCANNER Congratulations on purchasing your Actron Code Scanner for accessing engine trouble codes required for repairing vehicles equipped with computers Your Actron Code Scanner is made by Actron the largest and most trusted name in automotive diagnostic equipment for the home mechanic You can have confidence this product maintains the highest quality in manufacturing and will provide you years of reliable service This instruction manual is divided into several key sections You will find detailed steps on using the Code Scanner and important information about trouble code meanings how a computer controls engine operation and more
34. ain result then checks the results and corrects its actions if necessary until the desired results are achieved The oxygen sensor only works when it is very hot Also it can only monitor the hot engine air fuel mixture value and send back a signal to the computer The sensor can not monitor the other air fuel mixture values used during engine warm up so the computer must operate open loop at that time Acceleration Deceleration amp Idle Conditions As long as the engine and oxygen sensor are hot the computer can operate closed loop for best economy and least emissions During the drive conditions listed above the computer may have to ignore the sensor and run open loop relying on internal program ming for fuel delivery instructions During idle for example the oxygen sensor may cool down and stop sending a signal A different situation can occur during wide open throttle acceleration The computer sometimes adds additional fuel on purpose for temporary acceleration power The computer knows it is running rich so it ignores the sensor signal until the wide open throttle condition is over How the computer controls Idle Speed Throttle position and RPM sensors tell the computer when the vehicle is idling Sometimes an idle position switch on the throttle is used The computer merely watches RPM and adjusts an idle speed control device on the vehicle to maintain the desired idle con
35. ases they are very poisonous e Set the parking brake e Put shift lever in PARK automatic transmission or NEUTRAL manual transmission e Block the drive wheels e Stay away from moving engine parts 4 Start the Engine e Only use the ignition key to start engine do not use a remote starter e If engine will not start stalls or runs rough refer to vehicle service manual for troubleshooting charts related to the symptom 5 Check Engine Timing e Base timing should be the same as the VECI decal specification give or take 2 Example Specified timing is 10 BTDC Measured timing should be in the range of 8 to 12 BTDC Distributor System If base timing not correct adjust or repair as necessary before proceeding Refer to ignition system section in vehicle service manual for instructions Distributorless System Base timing is NOT adjustable If timing not correct refer to ignition system section in vehicle service manual for possible causes Repair as necessary before proceeding 6 Reconnect the In Line SPOUT or SAW Connector 7 Check for Timing Advance or RPM Increase e Timing change or RPM increase should occur as soon as connector is reconnected e If O K proceed to SELF TEST PART 4 e If not O K proceed to SELF TEST PART 4 but repair Engine Run codes 213 or 218 immediately if received 8 Turn Ignition Key to OFF Position 17 Self Test Part 4
36. ation or Electronic Distributorless Ignition System EDIS fault problems with Crankshaft Position Sensor CPS circuit 22 Manifold Absolute Pressure MAP sensor or Barometric Pressure BP sensor signal voltage out of specification engine off or not at normal vacuum levels engine running Throttle Position TP sensor signal voltage out of Self Test specification Air Charge Temperature ACT sensor or Vane Air Temperature VAT sensor signal voltage is out of specification engine off or not at normal levels engine running or Electronic Distributorless Ignition System EDIS fault failure in coil 1 primary circuit 25 Knock Sensor KS signal not detected during Engine Run Self Test Dynamic Response test Vane Air Flow VAF sensor or Mass Air Flow MAF sensor signal voltage out of Self Test specifications or Transmission Oil Temperature TOT sensor signal voltage is out of Self Test specification Vehicle Speed Sensor VSS signal voltage is too low Or Electronic Distributorless Ignition System EDIS fault failure in coil 2 primary circuit 28 Vane Air Temperature VAT sensor signal voltage out of Self Test specification or Electronic Distributorless Ignition System EDIS fault failure in coil 3 primary circuit or Distributorless Ignition System DIS fault Loss of right side TACH signal 29 Vehicl
37. aust Gas Oxygen HEGO sensor signal voltage too high 169 Downstream Heated Exhaust Gas Oxygen HEGO sensor signal voltage too low 171 Heated Exhaust Gas Oxygen HEGO sensor voltage signal not switching Bank 1 172 Heated Exhaust Gas Oxygen HEGO sensor voltage signal indicates lean Bank 1 173 Heated Exhaust Gas Oxygen HEGO sensor voltage signal indicates rich Bank 1 175 Heated Exhaust Gas Oxygen HEGO sensor voltage signal not switching Bank 2 176 Heated Exhaust Gas Oxygen HEGO sensor voltage signal indicates lean Bank 2 177 Heated Exhaust Gas Oxygen HEGO sensor voltage signal indicates rich Bank 2 179 Heated Exhaust Gas Oxygen HEGO sensor voltage signal not switching indicates rich during part throttle engine operation Bank 1 181 Heated Exhaust Gas Oxygen HEGO sensor voltage signal not switching indicates lean during part throttle engine operation Bank 1 182 Electronic Control Assembly ECA status adaptive rich limit reached in fuel control program engine idle Bank 1 3 Electronic Control Assembly ECA status adaptive lean limit reached in fuel control Boren engine idle Bank 1 184 Mass Air Flow MAF sensor signal voltage is higher than expected 2 185 Mass Air Flow MAF sensor signal voltage
38. ce codes to help pinpoint the problem Refer to Test Results Chart Code definitions are listed in Section 8 Code Meanings MCU system Key On KOER CODES 11 all except high altitude 62 high altitude V 6 or V 8 ONLY 65 high altitude l 4 ONLY Any Code s No Codes Received STO light always on or off Engine Running KOER Test Results ACTION TO TAKE System pass No problem found by computer during KOER Self Test The Self Test Diagnostic Procedure is complete If vehicle symptoms are still present they are probably not related to the computer system System pass No problem found by computer during KOER Self Test The Self Test Diagnostic Procedure is complete If vehicle symptoms are still present they are probably not related to the computer system System pass No problem found by computer during KOER Self Test The Self Test Diagnostic Procedure is complete If vehicle symptoms are still present they are probably not related to the computer system Codes indicate system problems are present now Write down all codes Refer to vehicle service manual for code troubleshooting charts and repair procedures Repeat PART 3 Key On Engine Running KOER Self Test after every repair You have a problem which must be repaired before proceeding Refer to the vehicle service manual Self Test Not Functional or similar title troubleshooting chart Note High Altitude refers t
39. coming air etc SFI or SEFI Sequential Fuel Injection or Sequential Electronic Fuel Injection A fuel injection system using one injector for each cylinder The injectors are mounted in the intake manifold The injectors are fired individually in the same sequence as the spark plug firing sequence Short circuit A fault condition an unwanted connection of one electric circuit to another causing a change in the normal current flow path Solenoid A device to convert an elec trical current to mechanical motion It consists of a coil of wire with a movable metal rod in the center When power is applied to the coil the resulting electromagnetism moves the rod and performs some mechanical action The ECA often uses solenoids to switch vacuum lines on and off This allows the ECA to control vacuum operated devices such as an EGR valve Fuel injectors are another type of solenoid Spark Retard Solenoid Used on MCU systems having a knock sensor The MCU module energizes this solenoid during engine knock conditions The solenoid bleeds vacuum from the distributor advance to retard spark timing SPOUT Spark Output signal from the ECA Sent to TFI IV or DIS ignition modules to fire the ignition coil s and create spark voltage 1 Shift Solenoid 1 Located in certain electronically controlled transmissions along with Shift Solenoid 2 The ECA energizes these solenoids one or both to engage the
40. correct gear ratio obtained for third gear 648 Transmission problem incorrect gear ratio obtained for fourth gear 649 Electronic Pressure Control EPC signal higher or lower than expected 651 Electronic Pressure Control EPC solenoid circuit failure 652 Modulated Lock Up Solenoid MLUS circuit failure 653 Transmission Control Switch TCS did not switch during Key On Engine Run Self Test 654 Manual Lever Position MLP sensor not indicating PARK position during Key On Engine Off Self Test 655 Manual Lever Position MLP sensor not indicating NEUTRAL position during Key On Engine Off Self Test 656 Converter Clutch Control continuous slip error 657 Excessively hot transmission oil temperature detected during engine operation 659 High vehicle speed detected while shift lever indicating PARK position 667 Manual Lever Position MLP sensor signal voltage too low 668 Manual Lever Position MLP sensor signal voltage too high Manual Lever Position MLP sensor signal voltage out of range 676 Transmission problem mechanical failure in first gear and reverse 677 Transmission problem mechanical failure in first gear and second gear 678 Transmission problem third gear to second gear downshift error 679 Transmission problem second gear to first gear downshift error 691 4x4
41. ction 5 Code Meanings EEC IV system 10 Turn Ignition Key to OFF Position Refer to KOER Test Results chart following Key On Engine Running KOER Test Results ENGINE ID CODE 2 3 40r 5 2 3 40r 5 98 or 998 DYNAMIC RESPONSE CODE 1 1 Not sent ENGINE RUNNING CODE 11 Any Codes Any Codes ACTION TO TAKE No problems found by computer during KOER Self or 111 Test however lf Continuous Memory codes were obtained in Self Test Part 2 go to SELF TEST PART 5 Evaluate Continuous Memory codes If Continuous Memory codes were NOT obtained in Self Test Part 2 BUT other vehicle symptoms are still present refer to Diagnosis by Symptom Troubleshooting Charts in vehicle service manual The faults are probably not related to the computer system If Continuous Memory codes were NOT obtained in Self Test Part 2 and NO other vehicle symptoms are present the Self Test Diagnostic Procedure is complete Engine Running codes indicate system problems are present now Write down all codes Make repairs based on Engine Running codes starting with the first code received Exception Take care of code 213 or 218 first if received Refer to vehicle service manual for code troubleshooting charts and repair procedures Repeat KOER Self Test after every repair Sometimes a repair procedure will eliminate more than one code The Key On Engine Running Self Test CANNOT be per
42. ctrical Connectors for Corrosion on pins Bent or damaged pins Contacts not properly seated in housing Bad wire crimps to terminals Problems with connectors are common in the engine control system Inspect carefully Note that some connectors use a special grease on the contacts to prevent corrosion Do not wipe off Obtain extra grease if needed from your vehicle dealer It is a special type for this purpose 3 Prepare Vehicle e Turn off all electrical equipment and accessories in vehicle e Keep all vehicle doors closed during testing e Make sure radiator coolant and transmission fluid are at proper levels e Start the engine and let it idle until the upper radiator hose is hot and pressurized and RPM has settled to warm engine idle speed Check for leaks around hose connections e Turn ignition key to OFF position 6 Have a Pencil WARNING Always operate vehicle and Paper in a well ventilated area Ready Do NOT inhale exhaust gases they e This is for are very poisonous writing down all the codes 4 Check Code Scanner Battery e Refer to Section 2 7 Go to SELF TEST PART 2 Key On Engine Off KOEO Self Test e Do Self Test Part 2 even if engine 5 Plug the Code Scanner into the will not start stalls or runs rough Vehicle Self Test Connectors The service codes you get may e Refer to Section 3 Connector pinpoint the problem If not refer to Location
43. d electrical signals to the MCU module The MCU module can then calculate throttle position and engine load 65 ONE 1 YEAR LIMITED WARRANTY Actron Manufacturing Company Actron warrants to the original purchaser that this prod uct will be free from defects in materials and workmanship for a period of one 1 year from the date of original purchase Any unit that fails within this period will be replaced or repaired at Actron s discretion without charge If you need to return product please follow the instruc tions below This warranty does not apply to damages intentional or accidental alterations or improper or unreasonable use DISCLAIMER OF WARRANTY ACTRON DISCLAIMS ALL EXPRESS WARRANTIES EXCEPT THOSE THAT APPEAR ABOVE FURTHER ACTRON DISCLAIMS ANY IMPLIED WARRANTY OF MERCHANT ABILITY OF THE GOODS OR FITNESS OF THE GOODS FOR ANY PURPOSE TO THE EXTENT ALLOWED BY LAW ANY IMPLIED WARRANTY OF MERCHANTABILITY OR OF FITNESS APPLICABLE TO ANY PRODUCT IS SUBJECT TO ALL THE TERMS AND CON DITIONS OF THIS LIMITED WARRANTY SOME STATES DO NOT ALLOW LIMITATIONS ON HOW LONG AN IMPLIED WARRANTY LASTS SO THIS LIMITATION MAY NOT APPLY TOA SPECIFIC BUYER LIMITATION OF REMEDIES IN NO CASE SHALL ACTRON BE LIABLE FOR ANY SPECIAL INCIDENTAL OR CONSE QUENTIAL DAMAGES BASED UPON ANY LEGAL THEORY INCLUDING BUT NOT LIM ITED TO DAMAGES FOR LOST PROFITS AND OR INJURY TO PROPERTY SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITAT
44. d with EEC IV systems This connector must be plugged into the Code Scanner before use The MCU system does NOT use the small pigtail connector Connector locations You can tell which computer system is in your vehicle by noting which connector type is installed The connectors are located in one of six general areas e Near the fire wall right or left side of vehicle e Near the wheel well right or left side of vehicle e Near the front corner of the engine compartment right or left side of vehicle The connectors are easy to miss take your time looking They are usually gray or other dark color and located close to a wiring harness They may be capped with a plastic cover or shroud labeled EEC TEST or similar wording Other Test Connectors Vehicles made after 1988 may have additional computer controlled systems installed such as Anti Lock Brakes ABS active suspension and the like These systems use a test connector identical to EEC IV six sided one These systems do NOT use the extra pigtail connector The Code Scanner is compatible with most of these systems refer to vehicle service manual for system description and test methods a E SSS EEC IV System Using the Code Scanner EEC IV Systems Complete Description for Reading and Using Service Codes Do This First This section shows you how to use the Code Scanner for e Running tests of the engine compute
45. desired transmission gear 63 Stepper Motor A special type of electric motor with a shaft that rotates in small steps instead of a continuous motion A certain sequence of frequency type signals is required to step the motor shaft A different signal sequence will step the shaft in the opposite direction No signals keeps the shaft still in position A constant signal drive will continuously rotate the shaft The shaft is usually connected to a threaded assembly which moves back and forth to control things such as throttle position The engine computer sends the correct signals to the motor for control STI Self Test Input See Self Test Input definition STO Self Test Output See Self Test Output definition TAB Thermactor Air Bypass solenoid Sometimes called AM 1 The ECA energizes this solenoid to apply vacuum and thus activate the TAB valve Normally this valve allows incoming air to pass into the rest of the system When activated the valve takes the incoming air and dumps it back into the atmosphere Refer to Thermactor Air System description for more details TAD Thermactor Air Diverter solenoid Sometimes called AM 2 The ECA energizes this solenoid to apply vacuum and thus activate the TAD valve Normally this valve directs incoming air to the catalytic converter When activated the valve takes the incoming air and and directs it to the exhaust manifold Refer to T
46. dition Note that this is another example of closed loop operation The computer performs an action activating an idle control device then watches the results of its action engine RPM and readjusts as necessary until the desired idle speed is achieved There are two types of idle speed control devices The first is an adjust able throttle stop that can be positioned by a computer controlled motor The second method allows the throttle to close completely then has a computer controlled solenoid to pass air around the closed throttle to set the idle speed Smaller engines can stumble or stall at idle when the air conditioner compres sor turns on or the power steering is used To prevent this switches tell the computer when these demands are coming so it can increase the idle accordingly A simple form of idle speed adjustment using a throttle kicker actuator is used on early EEC IV V 8 engines This device is described later in the MCU section How the computer controls Spark Advance Timing You set spark timing in a non computer engine by using a timing light and adjusting the distributor at idle RPM During vehicle operation timing is changed by either engine vacuum vacuum advance function or by engine RPM centrifugal advance function These spark timing changes are done mechanically inside the distributor Computer controlled vehicles using a distributor still have you set spark timing by using a t
47. e For example if repairs were made to the Engine Coolant Temperature ECT sensor circuit as the result of a KOEO code then a Continuous Memory code 21 ECT signal voltage too high would be disregarded 4 If any codes remain refer to vehicle service manual for Continuous Memory code troubleshooting charts and repair procedures 5 Erase Continuous Memory codes after all repairs have been made Erasing Continuous Memory Codes 1 Verify Ignition Key is in OFF Position 2 Put Code Scanner HOLD TEST Switch in HOLD Position 3 Turn Ignition Key to ON Position but DO NOT START THE ENGINE 4 Put Code Scanner HOLD TEST Switch in TEST Position e This starts the normal KOEO Self Test WARNING Stay away from the radiator cooling fan It may turn on momentarily On certain vehicles with electrically operated fans 5 Wait for the STO Light to Start Blinking Codes are Being Sent 6 Put Code Scanner HOLD TEST Switch in HOLD Position e The switch must be moved during the time the STO light is blinking the time period when codes are being sent 7 The Continuous Memory Codes are Now Erased 8 Turn Ignition Key to OFF Position 9 Disconnect Code Scanner CODE MEANINGS Code Definitions for FORD Engines with EEC IW Computer System Electronic Engine Control system version IV Code definitions are listed in this section e If more than one definition is listed consult your v
48. e HOLD The STI wire is unconnected Normal position no testing e TEST The STI wire is connected to vehicle ground Computer starts testing procedure CP9015 Ford Lincoln amp Mercury Domestic 1981 amp Newer e SELF TEST OUTPUT light This light is connected to the STO circuit coming from the computer e Light OFF The STO signal is high about 5 volts present e Light ON The STO signal is low near zero volts A pulse type signal on the STO wire will cause this light to blink This is how the computer sends test results to the Code Scanner See Section 4 or 7 for details Note With the Code Scanner con nected and ignition key OFF the light may be ON or OFF depends upon vehicle This does not affect testing performance 3 AUDIO switch e Switch ON A tone sounds whenever the Self Test Output light is lit e Switch OFF Tone is always OFF This feature is useful when the STO light can not be easily seen such as when performing the wiggle test described in Section 6 Note With the Code Scanner con nected Audio switch ON and ignition key OFF the tone may be ON or OFF no matter what the light does depends upon vehicle This does not affect testing performance Code Scanner Power A 9 volt transistor radio battery NEDA 1604 is required to power the Code Scanner Either a regular or alkaline battery may be used The Code Scanner has an au
49. e Speed Sensor VSS signal voltage is too low EGR Valve Position EVP sensor or Pressure Feedback EGR PFE sensor signal voltage is below minimum specification or EGR Vacuum Regulator EVR solenoid circuit problems or EGR valve is not in its normal closed position 32 EGR Valve Position EVP sensor or Pressure Feedback EGR PFE sensor signal voltage is below closed limit or has gone beyond set limits Or Problems with EGR valve controlling EGR Valve Position EVP sensor or Pressure Feedback EGR PFE sensor indicates EGR valve is not opening Or EGR Valve Position EVP sensor or Pressure Feedback EGR PFE sensor indicates EGR valve not seated closed properly 34 EGR Valve Position EVP sensor or Pressure Feedback EGR PFE sensor signal voltage out of Self Test specification limits Or signal voltage above closed limit during normal engine run operation Or signal indicates insufficient EGR flow 35 EGR Valve Position EVP sensor or Pressure Feedback EGR PFE sensor signal voltage above Self Test specification limits Or 23 signal voltage too high during normal engine run operation Or RPM too low to perform EGR test Engine Run Self Test 38 Idle Tracking Switch ITS circuit open Transaxle problem lock up failed in torque convertor Or convertor bypass clutch not applying properly 41 Exhaust Gas Oxygen EGO sensor vo
50. e connected with it for loss or damages suffered through reliance on any information contained in this manual or misuse of accompanying product Actron reserves the right to make changes at any time to this manual or accompanying product without obligation to notify any person or organization of such changes 66
51. e plug Refer to ignition system section in vehicle service manual for specific instructions BRAKE BOOSTER QRACRLAB For 1991 amp Older Vehicles See page 15 for 1992 amp newer vehicles 1 Turn Ignition Key OFF e Wait 10 seconds before proceeding 2 Put Code Scanner HOLD TEST Switch in HOLD Position WARNING The next step involves starting the engine Observe safety precautions e Always operate vehicle in a well ventilated area Do NOT inhale exhaust gases they are very poisonous e Set the parking brake e Put shift lever in PARK automatic transmission or NEUTRAL manual transmission e Block the drive wheels e Stay away from moving engine parts 3 Start the Engine e If engine will not start stalls or runs rough refer to vehicle service 4 Put Code 16 manual for troubleshooting charts related to the symptom Scanner HOLD TEST Switch in TEST Position e The computer is now performing an Engine Running Self Test but do not be concerned with the test or the resulting codes at this time It takes several seconds before codes are sent CP9015 Ford Lincoln amp Mercury Domestic 1981 amp Newer 5 Wait For End of All Service Code Signals e STO light on Code Scanner stops blinking 6 Check Ignition Timing e After the last code is sent the timing will remain fixed for 2 minutes unless Self Test is deactivated by moving Test Hold switch to HOLD po
52. e the only differences between an older engine and a computerized one A little later we will discuss just how the computer handles these tasks What has NOT changed A computer controlled engine is basically the same as earlier types It is still an internal combustion engine with pistons spark plugs valves and cams The ignition charging starting and exhaust systems are almost the same as well You test and repair these systems the same way as before using familiar tools The instruction manuals for these tools show you how to perform the tests Your compression gauge vacuum pump dwell tach meter engine analyzer timing light etc are still valuable The Engine Computer Control System The computer module is the heart of the system It is sealed in a metal box and linked to the rest of the system by a wiring harness The computer module is located in the passenger compartment usually behind the dashboard or front kick panels This protects the electronics from moisture extreme temperatures and excess vibration which are common in the engine compartment The computer is permanently pro grammed by factory engineers The program is a complex list of instructions telling the computer how to control the engine under various driving conditions To do its job the computer needs to know what is happening and then it needs devices to control things Sensors give the computer information The computer can only
53. ehicle service manual to get the specific meaning for your vehicle e Code meanings can vary with vehicle model year engine type options and type of test being per formed e Many of the codes listed may not apply to your vehicle e Follow vehicle service manual procedures to find the cause of the code Always start with the first code displayed Remember 1 Visual inspections are important 2 Problems with wiring and connectors are common especially for intermittent faults 3 Mechanical problems vacuum leaks binding or sticking linkages etc can make a good sensor look bad to the computer 4 Incorrect information from a sensor may cause the computer to control the engine in the wrong way Faulty engine operation might even make the computer show a different good sensor as being bad Three Digit Codes Certain 1991 and newer vehicles use 3 digit codes to report the results of the system Self Test procedure Refer to your vehicle service manual to determine if your system uses 2 or 3 digit codes The listing of 3 digit code meanings begins on page 24 11 System pass 12 System cannot raise engine speed above normal idle RPM out of specification during normal idle operation or D C motor does not follow dashpot 14 The Electronic Control Assembly ECA has detected an intermittent loss of Profile Ignition Pick up PIP signal during recent operation Failure
54. emoves service codes stored in computer memory Self Test Part 1 Test Preparation 1 Safety First e Set the parking brake e Put shift lever in PARK automatic transmission or NEUTRAL manual transmission e Block the drive wheels e Make sure ignition key is in OFF position 2 Perform Visual Inspection Doing a thorough visual and hands on underhood inspection before starting any diagnostic procedure is essential You can find the cause of many drivability problems by just looking thereby saving yourself a lot of time e Has the vehicle been serviced recently Sometimes things get reconnected in the wrong place or not at all e Don t take shortcuts Inspect hoses and wiring which may be difficult to see because of location beneath air cleaner housings alternators and similar components e Inspect the air cleaner and ductwork for defects e Check sensors and actuators for damage e Inspect all vacuum hoses for Correct routing Refer to vehicle service manual or Vehicle Emission Control Information VECI decal located in the engine compartment Pinches and kinks Splits cuts or breaks BRAKE BOOSTER TO TRANS MODE YRACSLAB 11 e Inspect wiring for Contact with sharp edges This happens often Contact with hot surfaces such as exhaust manifolds Pinched burned or chafed insulation Proper routing and connections Check Ele
55. esistance decreases with temperature It is located inside the vane meter assembly a housing between the air cleaner and throttle body through which all incoming air passes The ECA measures incoming air temperature with this sensor This information is used for fuel delivery calculations VCRM Variable Control Relay Module Contains electronic switches to control power to A C clutch engine cooling fan fuel pump etc ECA controls module A 2 wire DCL circuit carries ECA instruction signals to a computer circuit inside VCRM Power delivered by VCRM can be adjusted so that for example engine fan can be slowly turned on or run at various speeds VRS EEC IV systems Variable Reluctance Sensor A sensor mounted on the crankshaft which sends a frequency type signal to the ECA The ECA uses VRS to obtain information on crankshaft position and speed MCU systems Vacuum Regulator Solenoid Used with feedback carburetors having a vacuum controlled fuel metering system Feedback carburetors let the engine computer control air fuel ratios The MCU module sends a duty cycle signal to VRS which controls vacuum applied to the fuel metering rod in the carburetor See Duty Cycle definition A low duty cycle signal reduces control vacuum for rich operation A high duty cycle signal increases control vacuum for lean operation VSS Vehicle Speed Sensor This sensor mounted in the transmission
56. ey is in OFF position 2 Perform Visual Inspection Doing a thorough visual and hands on underhood inspection before starting any diagnostic procedure is essential You can find the cause of many drivability problems by just looking thereby saving yourself a lot of time e Has the vehicle been serviced recently Sometimes things get reconnected in the wrong place or not at all Don t take shortcuts Inspect hoses and wiring which may be difficult to see because of location beneath air cleaner housings alternators and similar components for defects Check sensors and actuators for damage Inspect all vacuum hoses for Correct routing Refer to vehicle service manual or Vehicle Emission Control Information VECI decal located in the a engine compart ment Pinches and kinks Splits cuts or breaks BRAKE BOOSTER TO TRANS QRACRLAB Inspect wiring for Contact with sharp edges This happens often Contact with hot surfaces such as exhaust manifolds Pinched burned or chafed insulation Proper routing and connections Check electrical connectors for Corrosion on pins Bent or damaged pins Contacts not properly seated in housing Bad wire crimps to terminals Problems with connectors are common in the engine control system Inspect carefully Note that some connectors use a special grease on the contacts to prevent
57. failure Or Idle Tracking Switch ITS circuit failure incorrect switch signal indications during Self Test 69 Transaxle problem Open circuit failures with 3 2 pressure switch or 3 4 pressure switch Or 3 4 switch error 70 Problem with Electronic Control Assembly ECA failure in Data Communications Link DCL 71 Problem with Electronic Control Assembly ECA software reset detected or Problem with Message Center Control Assembly MCCA failure in Data Communications Link DCL 72 Insufficient manifold vacuum change detected during Dynamic Response portion of Engine Run Self Test Or Problem with Message Center Control Assembly MCCA failure in Data Communications Link DCL Or Power interrupt detected Insufficient throttle position change detected during Dynamic Response portion of Engine Run Self Test 74 Brake ON OFF BOO switch action not detected during Dynamic Response portion of Engine Run Self Test 75 Brake ON OFF BOO switch always closed circuit 76 Insufficient Vane Air Flow VAF sensor change detected during Dynamic Response portion of Engine Run Self Test 17 Operator error during Dynamic Response portion of Engine Run Self Test 78 Power interrupt detected Or Flexible fuel sensor circuit failure 79 Air Conditioner A C on during Self Test 81 Thermactor Air Diverter TAD or AM 2 solenoid circuit
58. failure Or Idle speed adjust service pin in use circuit connected to ground Engine Coolant Temperature ECT sensor signal voltage is too low Or Indicates that the Idle Tracking Switch is open in contact with the throttle lever with the Idle Speed Control Motor fully retracted 62 Transaxle problem 4 3 or 3 2 pressure switch circuit failed closed Or convertor clutch failure Throttle Position TP sensor signal voltage is too low 64 Air Charge Temperature ACT sensor or Vane Air Temperature VAT sensor signal voltage is too low Electrical charging system problem occurred voltage too high over 17 5 volts 24 Or Engine control system never went into closed loop fuel operation Or Transaxle problem Overdrive Cancel Switch OCS was not cycled during Engine Run Self Test 66 Mass Air Flow MAF sensor or Vane Air Flow VAF sensor voltage signal too low Or Transmission Oil Temperature TOT sensor signal voltage is too low Improper signals are being received from either the Neutral Drive Switch NDS Neutral Gear Switch NGS Neutral Pressure Switch NPS Clutch Switch CS Manual Lever Position MLP sensor or Air Conditioner Clutch ACC Or Air Conditioner A C on during Self Test 68 Vane Air Temperature VAT sensor signal voltage is too low Or Transmission Temperature Switch TTS open circuit
59. formed The computer has spotted system problems which must be repaired before running this test Go to Part 2 Key On Engine Off KOEO Self Test and follow all steps 20 Self Test Part 5 Evaluate Erase Continuous Memory Codes Do this Part if Continuous Memory codes other than an 11 or 111 pass code were received during SELF TEST PART 2 Key On Engine Off KOEO and all other Parts of the Self Test procedure have been completed e Continuous Memory codes come from faults which occurred in the past The problem may still be present or it may have gone away Regardless the codes will remain in stored in computer memory for retrieval during Self Test Part 2 until e The codes are erased using the procedure detailed later in this part or e Power is removed from the computer for more than a few minutes NOTE The KAPWR circuit supplies vehicle battery power to the computer memory when the ignition key is off or e The problem goes away and does not reappear After at least 40 engine warm up cycles depends upon vehicle the code will automatically be erased from computer memory if the problem stays away during that time What to Do 1 Look at the list of Continuous Memory codes obtained during Self Test Part 2 Key On Engine Off KOEO 2 Previous repairs may have eliminated the causes of some or all of these codes 3 Disregard codes which are related to repairs already mad
60. g tests of the engine computer system e Reading service codes to pinpoint problem causes Before using this section Read Sections 1 and 2 to learn about service codes and the Code Scanner tool Read Section 3 to find the location of the Self Test connector in your vehicle The connector type will tell you whether you have an MCU system or an EEC IV system Read this section 7 if you have an MCU system Use Section 4 if you have an EEC IV system Self Test Summary The Self Test procedure also called Quick Test involves engine off and engine running tests The entire procedure is summarized below Each part is fully explained on the following pages IMPORTANT All parts must be performed as shown for accurate test results 39 Self Test Summary Part 1 TestPreparation e Safety First Follow all safety rules e Perform Visual Inspection This often reveals the problem e Prepare Vehicle Check choke voltage and warm up engine Part 2 Do Key On Engine Off KOEO Self Test e Get service codes to help pinpoint problems Part3 Do Key On Engine Running KOER Self Test e Get more service codes to pinpoint problems found during engine operating conditions Self Test Part 1 Test Preparation 1 Safety First e Set the parking brake e Put shift lever in PARK automatic transmission or NEUTRAL manual transmission e Block the drive wheels e Make sure ignition k
61. he injectors are fired individually in the same sequence as the spark plug firing sequence The test turns each injector on and off and checks for an RPM decrease Codes indicate cylinders which are weak or not contributing due to problems such as damaged injectors spark plugs and wiring The test must be run at the end of the normal Key On Engine Running Self Test procedure explained in Section 4 and may be repeated as often as desired Warning The following procedure involves starting the engine Always operate vehicle in a well ventilated area Exhaust gases are very poisonous 1 Safety First e Set the parking brake e Put shift lever in PARK automatic transmission or NEUTRAL manual transmission e Block the drive wheels 2 Make Sure Ignition Key is in OFF Position 3 Check Code Scanner Battery e Refer to Section 2 4 Connect Code Scanner e Refer to Section 3 e Plug BOTH test connectors into the Code Scanner 5 Put Hold Test Switch in HOLD Position 6 Have a Pencil and Paper Ready e This is for writing down the codes 7 Start the Engine e Stay away from moving parts 8 Put Hold Test Switch in TEST Position e Computer is now running normal Key On Engine Running Self Test 9 Wait For End of All Service Code Signals e STO light on Code Scanner stops blinking B egin the Cylinder Balance Test 10 Lightly Press and Release Throttle about 10 seconds after STO Light stops bli
62. hermactor Air System description for more details TDC Top Dead Center When a piston is at its uppermost position in the cylinder maximum compression TFI IV Thick Film Ignition system version 4 An ignition system consisting of a distributor ignition coil and TFI IV module The ECA controls the spark advance timing A camshaft position sensor in the distributor sends a reference signal called PIP to the ECA The ECA sends a spark advance signal called SPOUT to the TFI IV module which fires the spark coil The distributor mechanically switches the spark voltage to the various plugs in the usual manner The ECA determines optimum spark timing from sensor information engine speed and RPM throttle position coolant temperature engine load vehicle speed gear lever position and knock sensor condition Thermactor Air System An emission control system consisting of an air pump air flow control valves TAB amp TAD and a catalytic converter The converter removes pollutants from the exhaust stream An air pump brings outside air when needed and sends it either to the exhaust manifold upstream or directly into the converter downstream The ECA controls the air path for best performance under different engine operating conditions The air pump always runs when the engine runs Usually the incoming air is directed to the converter Air is kept out during extended idling prevent
63. ient RPM change during Dynamic Response Test Engine Run Self Test Or Invalid cylinder balance test throttle position movement Or Invalid cylinder balance test cylinder identification problems 539 Air conditioner or defroster on 542 Fuel Pump FP circuit open connection Electronic Control Assembly ECA to motor ground 543 Fuel Pump FP circuit open connection Electronic Control Assembly ECA to battery 29 551 Idle Air Control IAC solenoid circuit failure 552 Thermactor Air Bypass TAB or AM 1 solenoid circuit failure 553 Thermactor Air Diverter TAD or AM 2 solenoid circuit failure 554 Fuel Pressure Regulator Control FPRC circuit failure 555 SBS circuit failure 556 Fuel Pump FP relay primary circuit failure Low Speed Fuel Pump primary circuit failure EGR Valve Regulator EVR solenoid circuit failure 559 Air Conditioner Clutch ACC relay circuit failure Turbocharger Control Solenoid TCS output circuit failure 562 Auxiliary Electro Drive Fan AEDF circuit failure 563 High Speed Electro Drive Fan HEDF circuit failure 564 Electro Drive Fan EDF circuit failure 565 Cannister Purge CANP solenoid circuit failure 566 3 4 Shift solenoid circuit failure 569 Auxiliary Cannister Purge AUX CANP circuit failure 571 EGR vacuum solenoid circui
64. ifold Absolute Pressure MAP sensor vacuum hose disconnected or damaged 129 Manifold Absolute Pressure MAP sensor or Mass Air Flow MAF sensor insufficient signal value change during Dynamic Response test Engine Run Self Test 136 Heated Exhaust Gas Oxygen HEGO sensor voltage signal not switching during Engine Run Self Test Indicates lean Bank 2 137 Heated Exhaust Gas Oxygen HEGO sensor voltage signal not switching during Engine Run Self Test Indicates rich Bank 2 138 Cold Start Injector CSI insufficient flow during Engine Run Self Test 139 Exhaust Gas Oxygen EGO sensor no switching detected Bank 2 141 Fuel system indicates lean with high flow demand 144 Exhaust Gas Oxygen EGO sensor no o detected Bank 157 Mass Air Flow MAF sensor signal voltage is too low 158 Mass Air Flow MAF sensor signal voltage is too high 159 Mass Air Flow MAF sensor signal voltage is higher or lower than expected 165 Downstream Heated Exhaust Gas Oxygen HEGO sensor voltage signal indicates lean Bank 1 166 Downstream Heated Exhaust Gas Oxygen HEGO sensor voltage signal indicates rich Bank 1 167 Throttle Position TP sensor insufficient signal voltage change during Dynamic Response test 108 Run Self Test 16 Downstream Heated Exh
65. iming light and adjusting the distributor at idle RPM The timing changes which occur during vehicle operation however are controlled electronically The computer looks at sensors to determine vehicle speed engine load and temperature RPM throttle position coolant temperature and manifold pressure or mass air flow sensors are used Then the computer adjusts timing according to factory programmed instructions Some vehicles have a knock sensor The computer can fine tune the spark timing if this sensor signals an engine knock condition A timing advance signal is sent by the computer to an ignition module which eventually creates the spark Computer Controlled Emission Systems e EGR Valve The EGR valve lets exhaust gases re enter the intake manifold and mix with the incoming air fuel The presence of exhaust gases reduces combustion temperatures in the cylinders and this reduces poisonous NOx emissions The computer controls the flow of gases through the EGR valve The EGR system is only used during warm engine cruise conditions A partially open EGR valve at other times can cause stalling e Thermactor Air System This system works with the catalytic convertor The computer takes outside air from an air pump and directs it to the exhaust manifold or catalytic convertor as necessary for best emission performance Refer to Thermactor Air System in Reference Glossary for more explanation e F
66. in Electronic Control Assembly ECA problems with Keep Alive Memory 22 16 RPM too low during Engine Run Self Test lean fuel test or Idle Speed Control ISC RPM out of Self Test specification or Electronic Distributorless Ignition System EDIS fault Ignition Diagnostic Monitor IDM signal not received Or Exhaust Gas Oxygen EGO sensor signal voltage indicates rich during Engine Run Self Test lean air fuel conditions 17 Exhaust Gas Oxygen EGO sensor signal voltage indicates rich during Engine Run Self Test lean air fuel conditions or RPM too low during Engine Run Self Test rich fuel test or Idle Speed Control ISC RPM below Self Test specification Loss of TACH signal to Electronic Control Assembly ECA or Distributorless Ignition System DIS fault primary circuit failure in coil 1 2 3 or 4 Or Electronic Distributorless Ignition System EDIS fault failure in Spark Angle Word SAW circuit 19 Failure in Electronic Control Assembly ECA problems with internal voltage regulator Or RPM too low for EGR check during Engine Run Self Test Or Cylinder Identification CID sensor input failure 21 Engine Coolant Temperature ECT sensor signal voltage out of range Key On Engine Off Self Test not at normal operating temperature Engine Run Self Test or loss of signal during normal engine oper
67. ine computer do Learn more about how your engine computer operates and controls vehicle functions oooccccccconccnccnc 49 10 Reference Glossary Includes component descriptions and term definitions commonly used in reference to engine computer SYSTEMS orreee Eroen IETARI tenes 55 Instrucci nes en espa ol67 Instructions en francais1 31 General Safety Guidelines to follow when working on vehicles e Always wear approved eye protection e Always operate the vehicle in a well ventilated area Do not inhale exhaust gases they are very poisonous Always keep yourself tools and test equipment away from all moving or hot engine parts e Always make sure the vehicle is in park Automatic transmis sion or neutral manual transmission and that the parking brake is firmly set Block the drive wheels e Never leave vehicle unattended while running tests Never lay tools on vehicle battery You may short the terminals together causing harm to yourself the tools or the battery e Never smoke or have open flames near vehicle Vapors from gasoline and charging battery are highly flam mable and explosive Always keep a fire extinguisher suitable for gasoline electrical chemical fires handy e Always turn ignition key OFF when connecting or disconnect ing electrical components unless otherwise instructed Always follow vehicle manufacturer s warnings cautions and service procedures CAUTION Some vehicle
68. ing idle speed if power steering is being used Quick Test Another name for Self Test See Self Test definition Relay A mechanical device for switching high current circuits on and off It is electronically controlled by a low current circuit Relays allows a low power ECA signal to control a high power device such as an electric cooling fan ROM Read Only Memory This is inside the ECA The ROM contains permanent programming information the ECA needs to operate a specific vehicle model Included are vehicle weight engine and transmission type axle ratio and other specifics SAW Spark Advance Word A signal used in some Distributorless Ignition Systems Sent from the ECA to the DIS ignition module to control spark advance timing The SAW signal is a series of voltage pulses The width of the pulses is what tells the DIS module what timing is desired wider pulses mean less spark advance An extra wide pulse puts the DIS module in a repetitive spark mode where several sparks are generated for every cylinder firing used on some vehicles at idle for lower emissions and smoother performance Self Test Sometimes called Quick Test A series of tests built into the ECA which help locate vehicle problems The Code Scanner is used to perform the tests and get the results in the form of code numbers Self Test Connector The connector that the Code Scanner plugs into for te
69. ing the injectors close to an intake valve port 57 CID Cylinder Identification signal This is a frequency type signal coming from a camshaft mounted sensor The ECA uses this signal to reference fuel injector operation and synchronize spark plug firing on distributorless ignitions Closed Loop C L This is when a control system performs an action expecting a certain result then checks the results and corrects its actions if necessary until the desired results are achieved Example The ECA pulses a fuel injector expecting a certain amount of fuel to be delivered In closed loop operation the ECA uses a sensor to check the actual amount of fuel delivered The ECA will correct the injector pulse width as necessary to obtain the desired fuel delivery Continuity An unbroken continuous circuit through which an electric current can flow Coolant Temperature Switches Used on MCU systems These are vacuum controlled electrical switches which signal various engine operating temperatures to the MCU module A ported vacuum switch is used along with the temperature switches The normally closed ported vacuum switches open at a specific temperature and allow vacuum to pass This vacuum then causes the temperature switches to switch and send a signal to the MCU module Some MCU systems use a single Low Temperature Switch to tell the MCU module when the engine has warmed up Other MCU systems use two
70. is lower than expected 186 Injector pulsewidth higher than expected or Mass Air Flow MAF sensor signal voltage is lower than expected 187 Injector pulsewidth lower than expected or Mass Air Flow MAF sensor signal voltage is higher than expected 188 Heated Exhaust Gas Oxygen HEGO sensor voltage signal not switching indicates rich during part throttle engine operation Bank 2 189 Heated Exhaust Gas Oxygen HEGO sensor voltage signal not switching indicates lean during part throttle engine operation Bank 2 191 Electronic Control Assembly ECA status adaptive rich limit reached in fuel control program engine idle Bank 2 192 Electronic Control Assembly ECA status adaptive lean limit reached in fuel control program engine idle Bank 2 193 Flexible Fuel Sensor circuit failure 211 Profile Ignition Pick Up PIP sensor circuit failure 212 Loss of Ignition Diagnostic Monitor IDM signal short to ground in Spark Output SPOUT circuit 213 Spark Output SPOUT circuit open connection failure 214 Cylinder Identification CID sensor circuit failure 215 Ignition system distributor less problem Coil 1 primary side circuit failure 216 Ignition system distributor less problem Coil 2 primary side circuit failure 17 Ignition system distributor less problem Coil 3
71. is always closed 1 6 Closed Throttle Vacuum Switch circuit is always closed 50 COMPUTER BASICS What does the Engine Control Computer do EEC IV and MCU This section explains the EEC IV engine computer control system the types of sensors and how the computer controls fuel delivery idle speed spark timing and emission devices The MCU system is described later but this entire section must still be read for complete under standing The following is an introduction to computer controlled engine systems Additional information may be found in books dealing with this subject available at your local library or auto parts store The more you know about the computer system the better and faster you can troubleshoot and fix problems Why Computers Computer controls were installed in vehicles to meet Federal Government regulations for lower emissions and better fuel economy This all began in the early 1980 s when purely mechanical control systems just were not good enough anymore A computer could be programmed to precisely control the engine under various operating conditions and eliminate some mechani cal parts making the engine more reliable What the computer controls The main control areas of the computer are e Fuel delivery e Idle speed e Spark advance timing e Emission devices EGR valve carbon cannister etc The changes made to the basic engine to allow a computer to control these tasks ar
72. itio SCANNER JA OFF HOLD CP9015 Ford Lincoln amp Mercury Domestic 19818 Newer e Computer is now running normal Key On Engine Off Self Test WARNING Stay away from electric motor driven radiator fan It may turn on during this procedure 8 Wait For End of All Service Code Signals e STO light on Code Scanner stops blinking 9 Output State Check is Now Activated Fully depress and release the throttle At this time most of the computer controlled relays and solenoids except fuel pump and fuel injectors will be energized NOTE The STO circuit is also energized so the STO light on the Code Scanner will turn on too e Repeat the action of depressing and releasing the throttle This will de energize the components STO light will turn off also e Throttle action may repeated as often as desired to turn the actuators on and off NOTE If vehicle is equipped with Integrated Vehicle Speed Control IVSC disconnect vacuum supply hose from the Speed Control Servo to release stored vacuum Otherwise the Speed Control Solenoids will energize the first time the throttle is depressed causing the servo to hold the throttle wide open Reconnect the vacuum hose after testing 10 Turn Ignition Key to OFF Position 11 Disconnect Code Scanner Part 2 Cylinder Balance Test This test is only used on vehicles with Sequential electronic Fuel Injection SFI engines Where t
73. learned by the ECA during normal engine operation Keypower The circuit which provides power to the engine control system Includes the ignition key switch Knock Sensor The ECA uses this device to detect engine detonation knocking When spark knock occurs the sensor sends a pulsing signal The ECA than retards spark advance until no detonation is sensed The sensor contains a piezoelectric element and is threaded into the engine block Vibrating the element generates the signal Special construction makes the element only sensitive to the engine vibrations associated with knocking LED Light Emitting Diode A semiconductor device which acts like a miniature light bulb When a small voltage is applied the LED glows LED s may be red orange or yellow or green They are often used as indicators or in numeric displays LUS Lock Up solenoid Located in automatic transaxle The ECA uses this solenoid to control the lock up clutch in the torque converter The ECA will engage or release lock up depending upon engine operation 61 MAF Mass Air Flow sensor This sensor measures the amount of air entering the engine and sends a voltage signal to the ECA The signal voltage increases when the amount of incoming air goes up This gives the ECA information required for control of fuel delivery spark advance and EGR flow MAP Manifold Absolute Pressure sensor This sensor measures manifold vacu
74. lems are found Allow the engine to idle until the upper radiator hose is hot and pressurized and RPM has settled to warm engine idle speed Check for leaks around hose connections e Turn ignition key to OFF position 4 Plug the Code Scanner into the Vehicle Self Test Connector e Refer to Section 3 Connector Location The Self Test connector is near the MCU computer module Not used in MCU systems e Connect the Code Scanner to the 6 sided test connector only The Code Scanner has a spot for a second small connector which is NOT USED in MCU systems Do not connect anything to this unused location The Code Scanner will not harm the vehicle engine computer 5 Do Special Set Up Procedures The engine types listed require additional preparation before continuing with the Self Test In Line 4 and 6 cylinder engines with a canister control valve Remove hose from connection port B This hose runs between the canister control valve and the carbon canister Do NOT plug the hose for the remainder of the test procedure Be sure to reconnect the hose after testing and servicing is completed V 6 and V 8 engines Remove PCV valve from breather cap on valve cover Be sure to replace PCV valve after testing and servicing is completed 2 3L engines with the GK code Manifold Vacuum Remove f cap Anti backfire vacuum switch Microcomeuter i Contra E1ZF 124651 C1A Urr Remove
75. linder Injector problem 6 Cylinder Injector problem 7 Cylinder Injector problem 8 Cylinder Injector problem Throttle was moved during test Testing could not be completed Repeat test procedure starting from step 1 i 9 1 2 3 4 5 6 7 8 NJ N 13 Turn Ignition Key to Off Position 14 Disconnect Code Scanner 36 Part 3 Wiggle Test Sometimes called Continuous Monitor test e This test can help locate intermittent faults in SOME circuits see chart on page 36 e When Wiggle test is activated the Code Scanner STO light and Audio tone will turn on if a problem is detected e The STO light and tone are only energized as long as the fault is present If the problem goes away the light and tone will turn off e If the STO light and tone come on as you wiggle a sensor connector or wiring that s where the problem is 1 Safety First e Set the parking brake e Put shift lever in PARK automatic transmission or NEUTRAL manual transmission e Block the drive wheels 2 Make Sure Ignition Key is in OFF Position 3 Check Code Scanner Battery e Refer to Section 2 4 Connect Code Scanner e Refer to Section 3 e Plug BOTH test connectors into the Code Scanner 5 Put HOLD TEST Switch in HOLD Position 6 Put AUDIO Switch in ON Position 7 Turn Ignition Key to ON Position but DO NOT START ENGINE 8 Depending upon Vehicle Model Year e 198
76. ltage signal always lean low value does not switch 42 Exhaust Gas Oxygen EGO sensor voltage signal always rich high value does not switch Exhaust Gas Oxygen EGO sensor voltage signal lean low value during wide open throttle driving condition Or sensor has cooled down and may not have responded properly during Engine Run Self Test 44 Problems in Thermactor Air Control system 45 Thermactor air flow is always upstream during Engine Run Self Test or Distributorless Ignition System DIS or Electronic Distributorless Ignition System EDIS problems primary circuit failure in coil 1 2 30r4 46 Thermactor Air System unable to bypass air vent to atmosphere or Distributorless Ignition System DIS or Electronic Distributorless Ignition System EDIS problems primary circuit failure in coil 2 47 Exhaust Gas Oxygen EGO sensor signal voltage indicates rich during lean air fuel conditions Or Vane Alr Flow VAF sensor voltage signal is too low or Transaxle problem 4x4L switch is closed 48 Vane Air Flow VAF sensor voltage signal too high or Distributorless Ignition System DIS problems Coil 3 circuit failure or Loss of left side TACH signal or Exhaust Gas Oxygen EGO sensor signal voltage indicates opposite from fuel 49 Electronic Distributorless Ignition System EDIS
77. lts Chart Key On Engine Off KOEO Test Results CONTINUOUS KOEO SEPARATOR MEMORY CODES CODES CODES 11 1 11 or 111 or 111 Any 1 11 Code s or 111 Any 1 Any Code s Code s 11 1 Any Code s or 111 not in Exceptions List CONTINUOUS MEMORY CODE EXCEPTIONS REPAIR NOW ACTION TO TAKE System pass No problem found by computer during KOEO Self Test No codes stored in computer memory Go to SELF TEST PART 3 Check Engine Timing Note lf engine will not start stalls or runs rough refer to vehicle service manual for troubleshooting charts related to the symptom KOEO codes indicate system problems are present now Write down all codes Make repairs based on KOEO codes starting with the first code received Refer to vehicle service manual for code trouble shooting charts and repair procedures Repeat KOEO Self Test after every repair Sometimes a repair procedure will eliminate more than one code Do not proceed to SELF TEST PART 3 until a KOEO pass code 11 or 111 is received KOEO and Continuous Memory codes indicate system problems Write down ALL codes DO NOT repair Continuous Memory codes at this time But keep them written down for later use in Self Test Step 5 First make repairs based on KOEO codes starting with the first code received Refer to vehicle service manual for code troubleshooting charts and repair procedures Repeat KOEO Self Test after every repair Sometimes a repair procedure will elimi
78. ly closed Applying vacuum opens the valve EGR C EGR Control solenoid Used in certain EGR systems The ECA energizes this actuator to apply vacuum and thus open the EGR valve Used along with the EGR V solenoid EGR S O EGR valve Shut Off solenoid Used in mechanically operated EGR systems where the ECA does not control EGR flow The ECA can completely stop flow by energizing this solenoid if engine operating conditions require this EGR V EGR Vent solenoid Used in certain EGR systems The ECA energizes this actuator to vent vacuum and thus close the EGR valve Used along with the EGR C solenoid 99 EHC Exhaust Heat Control solenoid The ECA energizes this solenoid to apply vacuum and thus activate the EHC valve When activated this valve diverts hot gases from the exhaust manifold to the intake manifold heat riser pad Heat is transferred from the exhaust gas to the riser pad which in turn heats the incoming air This aids in fuel atomization for better combustion efficiency during engine warm up Electronic Instrument Cluster A vehicle instrument panel using electronic displays numbers or bar graph type in place of standard gauges Receives information from the ECA by using the Data Communications Link DCL Electromagnetic Interference Undesired signals interfering with a needed signal For example static on a radio brought about by lightning flashes or closeness to high vol
79. n on momentarily during the test procedure On certain vehicles with electrically operated fans 5 Get Codes from the Flashing STO Light NOTE If the light does not flash go back and repeat SELF TEST PART 2 starting with Step 1 If the light still does not flash you have a problem which must be repaired before proceeding Refer to the vehicle service manual No Codes trouble shooting chart e Pay no attention to the brief rapid blinks which occur before the regular codes are sent e Count flashes to get service codes Code 12 looks like J2 PAUSE 30250 FLASH pause FLASH FLASH FLASH 1 FLASH FLASH 2 Put 1 and 2 together code 12 o y Code 23 looks like NZ NZ ATA PAUSE FLASH FLASH ES FLASH FLASH FLASH NOTE Certain 1991 and newer vehicles use 3 digit codes refer to vehicle service manual to determine whether your system uses 2 or 3 digit codes These codes are sent as follows Code 123 looks like NUNS Ny y Ny se PAUSE 797747 PAUSE WIRT FLASH pause FLASH FLASH pause FLASH FLASH FLASH e Two groups of codes are sent at this time Each group is separated by a single flash called a separator code The first code group has KOEO Key On Engine Off codes for problems which are present now Some service manuals call these hard or on demand codes The KOEO group will always contain at least one code This will
80. nate more than one code Do not proceed to SELF TEST PART 3 until a KOEO pass code 11 or 111 is received Continuous Memory codes indicate system faults Write down ALL codes but DO NOT repair these codes at this time Keep them written down for later use in Self Test Step 5 Continue the Self Test procedure go to SELF TEST PART 3 EXCEPTIONS Some Continuous Memory codes must be repaired before going to Part 3 These are listed below Refer to vehicle service manual for code troubleshooting charts and repair procedures Repeat KOEO Self Test after every repair Do not proceed to SELF TEST PART 3 until all code exceptions are eliminated 15 1989 amp older 56 66 1988 1989 5 0L SFI Mustang only 45 46 48 215 216 217 232 and 238 vehicles with DIS Distributorless Ignition System only 15 Self Test Part 3 Check Engine Timing NOTE 7 3L Diesel This ae Part does not apply Go to Part 4 This portion of the Self Test procedure is where you check both the base engine timing no computer adjustment and the ability of the computer to control spark advance The correct value for base engine timing is printed on the Vehicle Emission Control Information VECI decal located in the engine compartment Base timing is 10 BTDC if not specified on the VECI decal A timing light is required for this test Connect it to vehicle according to manufacturers directions For 2 3L dual plug engines use exhaust sid
81. ncorporated Haynes Publications P O Box 07150 861 Lawrence Drive Detroit MI 48207 Newbury Park CA 91320 1985 amp Newer Emission Diagnosis Cordura Publications Engine Electronics Mitchell Manuals Inc 1981 1984 Engine Emissions P O Box 26260 Diagnosis San Diego CA 92126 Electronic Engine Controls Fuel Injection and Feedback Carbure tors Fuel Injection and Electronic Engine Controls Emissions Control Manual Or similar titles Scanner Basics When Do You Use it and What Does it Do When to Use the Code Scanner Use the Code Scanner e When you experience a driveability problem with your vehicle e When the Check Engine light comes on if used on vehicle e For a routine system check even on vehicles with a Check Engine light What the Code Scanner Does The Code Scanner makes the vehicle computer run special tests to check out various parts of the system The Code Scanner plugs into vehicle wiring which connects directly into two engine computer circuits One circuit is called Self Test Input STI The Code Scanner uses this wire to tell the computer to run the tests The other circuit is called Self Test Output STO The computer sends test results back to the Code Scanner by using a pulse type signal on this wire Code Scanner Controls D HOLD TEST switch This switch connects to the computer s Self Test Input STI circuit
82. nking e Do NOT press throttle all the way down Exception Do brief wide open throttle for 1986 only e Test time is less than 3 minutes Do not move throttle until test is over 11 Get Codes from Flashing STO Light e Count flashes to get codes NOTE This test can give single digit codes Code 3 looks like Code 12 looks like jl Seb PAUSE 3 gt FLASH pause FLASH FLASH FLASH 1 FLASH FLASH 2 Put 1 and 2 together code 12 e Testing is complete 12 Optional Retest 1987 8 Newer can tell you how weak a bad e Lightly press and release throttle cylinder is The computer alters within 2 minutes after the last code inspection during retest Test is sent This will repeat the entire results will be different for a good cylinder balance test weak or dead cylinder See charts below using cylinder 7 as an e IMPORTANT Some 1987 and all example 1988 amp newer Repeating the test Example All cylinders equal 1st TEST 2nd TEST 3rd TEST Code 9 pass Not necessary Example Cylinder 7 is weak 4st TEST Code 7 3rd TEST Not necessary 2nd TEST Code 9 pass ii Example Cylinder 7 is very weak 1st TEST 2nd TEST 3rd TEST Example Cylinder 7 is extremely weak or dead 1st TEST 2nd TEST 3rd TEST Test Results System PASS 1 Cylinder Injector problem 2 Cylinder Injector problem 3 Cylinder Injector problem 4 Cylinder Injector problem 5 Cy
83. o vehicles with computer adjusted for operation at high elevations such as in Denver Colorado 48 CODE MEANINGS Code Definitions for FORD Engines with MCU Computer System Microprocessor Control Unit Code definitions are listed in this section e Many of the codes listed may not apply to your vehicle e Use the definition that applies to your engine type In Line 4 or 6 cylinder l 4 l 6 or V 6 or V 8 e Follow vehicle service manual procedures to find the cause of the code Remember 1 Visual inspections are important 2 Problems with wiring and connectors are common especially for intermittent faults 3 Mechanical problems vacuum leaks binding or sticking linkages etc can make a good sensor look bad to the computer 11 High Altitude computer adjusted for operation at high elevations such as in Denver Colorado l 4 All except High Altitude System pass 1 4 High Altitude only Altitude ALT circuit is open l 6 System pass V 6 All except High Altitude System pass V 6 High Altitude only Altitude ALT circuit is open V 8 All except High Altitude System pass V 8 High Altitude only Altitude ALT circuit is open 12 V 8 RPM out of specification Throttle Kicker TK system 25 V 8 Knock Sensor KS signal not detected during Key On Engine Run KOER Self Test 33 All Engines Key On Engine Run KOER Self Test not initiated
84. pressurized fuel supply The pressure is created by a fuel pump No flow occurs when the injector is off not energized When the injector is powered it opens fully allowing the fuel to flow The ECA controls fuel delivery by varying the amount of time the injectors are turned on FP Fuel Pump relay The ECA energizes this relay to apply power to the vehicle fuel pump For safety reasons the ECA removes power from the fuel pump when ignition signals are not present FPM Fuel Pump Monitor signal This is a wire between the ECA and the fuel pump motor power terminal The ECA uses this signal to verify when voltage is at the fuel pump for diagnosing fuel system problems Ground The return path for current to flow back to its source Usually the negative battery terminal It is also the reference point from which voltage measurements are made That is it is the connection place for the minus test lead from the voltmeter 60 HEDF High speed Electro Drive Fan relay The ECA energizes this relay when it determines extra engine cooling more than that provided by EDF is necessary Depending upon the vehicle the HEDF relay will either speed up the same fan used by EDF or it will turn on a second fan mounted in front of the radiator HEGO Heated Exhaust Gas Oxygen sensor An EGO sensor see EGO definition having a built in electric heating element The heater reduces sensor warm up time
85. r system Engine off ignition timing and engine running tests e Reading service codes to pinpoint problem causes Before using this section Read Sections 1 and 2 to learn about service codes and the Code Scanner tool Read Section 3 to find the location of the Self Test connector in your vehicle The connector type will tell you whether you have an EEC IV system or an MCU system Read this section 4 if you have an EEC IV system Use Section 7 if you have an MCU system Self Test Summary The Self Test procedure also called Quick Test involves engine off and engine running tests The entire procedure is Summarized in the chart Each part is fully explained on the following pages IMPORTANT All parts must be performed as shown for accurate test results Part 1 Test Preparation e Safety First Follow all safety rules e Perform Visual Inspection This often reveals the problem e Prepare Vehicle Engine must be thoroughly warmed up Part 2 To Key On Engine Off KOEO Self Test e Get service codes to help pinpoint problems Part 3 Check Engine Timing e Verify correct base timing no computer control before doing next part Part 4 Do Key On Engine Running KOER Self Test e Get more service codes to pinpoint problems found during engine operating conditions Part 5 Evaluate Erase Continuous Memory Codes e Helps locate intermittent problems e R
86. r out of gear NPS Neutral Pressure Switch Located in automatic transaxle The ECA uses this switch to determine when the transaxle is in or out of gear ocs Overdrive Cancel Switch Used by vehicle operator Signals ECA to prevent shifting transmission into overdrive 4th gear regardless of operating conditions OCIL Overdrive Cancel Indicator Light Located in passenger compartment Light turns on when vehicle operator uses Overdrive Cancel Switch to disable 4th gear transmission operation Open circuit A break in the continuity of a Circuit such that no electrical current can flow Open Loop O L This is when a control system performs an action expecting a certain result but has no way of verifying if the desired results were achieved Example The ECA pulses a fuel injector expecting a certain amount of fuel to be delivered The ECA assumes everything in the fuel system is operating as expected In open loop operation the ECA has no way of checking the actual amount of fuel delivered Thus a faulty injector or incorrect fuel pressure can change the amount of fuel delivered and the ECA would not know it Outputs Electrical signals sent from the ECA These signals may activate relays or other actuators for control purposes around the vehicle The signals can also send information from the ECA to other electronic modules such as ignition or trip computer Pressure Feedback E
87. re no other code groups or separator signals sent e Pay no attention to the brief rapid blinks which occur before the regular codes are sent e Count flashes to get service codes This is done the same way as in Self Test Part 2 Code 12 looks like Seb PAUSE 3 gt FLASH pause FLASH FLASH FLASH 1 FLASH FLASH 2 Put 1 and 2 together code 12 Code 23 looks like A SS PAUSE FLASH FLASH pause FLASH FLASH FLASH NOTE Certain 1991 and newer vehicles use 3 digit codes refer to vehicle service manual to determine whether your system uses 2 or 3 digit codes These codes are sent as follows Code 123 looks like NUNS NUNN WN FLASH pause FLASH FLASH pause FLASH FLASH FLASH ee PAUSE 47747 PAUSE 78 gt e The KOER Key On Engine 19 Running codes are sent as a group The KOER group will always contain at least one code This will be a system pass code 11 or 111 if no problems are seen The KOER code group is sent twice So you can double check your code list e Code sequence example with KOER codes 21 and 32 VARI JCC PAUSE X FLASH FLASH pause FLASH longer pause i FLAS pause I LASH FLASH FLASH FLASH longer pause 1 e AAA 1 AS FLASH FLASH pause FLASH longer pause FLAS sE LASH FLASH pause FLASH FLASH e Write down codes in the order they are sent e Code definitions are listed in Se
88. re noted by the test program and the results are stored in the computer s memory These tests are important The computer can not control the engine properly if it has bad inputs or outputs Code numbers give test results The test results are stored by using code numbers usually called trouble codes or service codes For example a code 63 might mean throttle position sensor signal voltage is too low Code meanings are listed in Sections 5 and 8 Specific code definitions vary with manufacturer engine and model year so you may want to refer to a vehicle service manual for additional information These manuals are available from the manufacturer other publishers or your local public library See manual listing on page 4 Read Codes with the Code Scamner You obtain trouble codes from the engine computer memory by using the Actron Code Scanner tool Refer to section 4 or 7 for details After you get the trouble codes you can either e Have your vehicle professionally serviced Trouble codes indicate problems found by the computer or e Repair the vehicle yourself using trouble codes to help pinpoint the problem Trouble Codes and Diagnostics help you fix the problem To find the problem cause yourself you need perform special test procedures called diagnostics These procedures are in the vehicle service manual There are many possible causes for any problem For example suppose yo
89. rge area The computer uses FBCA to vary this metered air and control air fuel mixtures anywhere from rich to lean FCS Feedback Control Solenoid Used on feedback carburetors those where the engine computer controls the air fuel ratio This solenoid receives a duty cycle signal from the computer See Duty Cycle definition The solenoid introduces fresh air from the air cleaner into the idle and main system vacuum passages A low duty cycle signal reduces air passing through the solenoid for rich operation A high duty cycle signal increases air passing through the solenoid for lean operation FMEM Failure Management and Effects Mode The name given to the way the ECA operates when failures are detected in sensor or actuator circuits and normal operation is no longer possible The ECA runs the engine the best way it can until the vehicle driver can get the problem repaired The effect on engine performance can be slight or severe Frequency The frequency of an electronic signal is a measure of how often the signal repeats a voltage pattern in a one second time span For example suppose a signal starts at zero volts goes to five volts then returns to zero again If this pattern repeats itself 100 times in one second then the signal frequency is 100 cycles per second or 100 Hertz Fuel Injector An electronically controlled flow valve Fuel injectors are connected to a
90. s various actuators to control the engine Sometimes vehicles have additional computers controlling other functions These include anti lock brake and active suspension systems ECT Engine Coolant Temperature sensor This sensor is a thermistor a resistor whose resistance decreases with increases in temperature The sensor is threaded into the engine block and contacts the engine coolant The ECA uses this signal for control of fuel delivery spark advance EGR flow and other emission control devices EDF Electro Drive Fan relay The ECA energizes this relay to apply power to the Electro Drive Fan mounted in front of the radiator for engine cooling purposes The fan is only turned on when the ECA determines cooling is necessary EDIS Electronic Distributorless Ignition System Ford technical manuals use EDIS when referring toa particular distributorless ignition system where a separate module EDIS module directly controls spark firing and synchronization All the ECA does is send a signal requesting a particular spark timing based on engine operation Refer to SAW definition The EDIS module and associated sensors take care of all other aspects of ignition system operation EEC IV Electronic Engine Control system version 4 The name for Ford s computerized engine control system used on vehicles starting in 1983 The system consists of a control module ECA containing a computer and
91. s are equipped with safety air bags You must follow vehicle service manual cautions when working around the air bag components or wiring If the cautions are not followed the air bag may open up unexpectedly resulting in personal injury Note that the air bag can still open up several minutes after the ignition key is off or even if the vehicle battery is disconnected because of a special energy reserve module About Codes Where do they come from and what are they for Engine computers can find problems The computer system in today s vehicles does more than control engine operation it can help you find problems too Special testing abilities are permanently programmed into the computer by factory engineers These tests check the components connected to the computer which are used for typically fuel delivery idle speed control spark timing and emission systems Mechanics have used these tests for years Now you can do the same thing by using the Actron Code Scanner tool Engine computers perform special tests The engine computer runs the special tests The type of testing varies with manufacturer engine model year etc There is no universal test that is the same for all vehicles The tests examine INPUTS electrical signals going IN to the computer and OUTPUTS electrical signals coming OUT of the computer Input signals which have wrong values or output circuits which don t behave correctly a
92. s called Low Mid and High vacuum switches a Zone Vacuum Switch assembly Other names are Wide Open Throttle Crowd and Closed Throttle vacuum switches Tach Signal information The MCU system monitors this ignition signal to measure engine RPM A wire connects the computer to the Tach terminal on the ignition coil The computer watches RPM to insure smooth operation when the air fuel mixture is changed Knock Sensor information Some MCU systems have a Knock Sensor which sends a pulse signal to the computer when an engine knock condition occurs How MCU controls Fuel Delivery The MCU computer controls air fuel delivery using a Feedback Carburetor The choke and idle cam mechanisms are similar to those on a conventional carburetor e One version has the computer controlling a fuel metering rod inside the carburetor The computer controls an electric motor Feedback Carburetor Actuator to position this rod e Another method uses a fuel metering rod positioned by vacuum The computer controls vacuum to this rod by using a Vacuum Regulator Solenoid The computer sends a duty cycle signal see definition in Reference Glossary to the solenoid to vary vacuum e A third version has the computer controlling air into the carburetor idle and main system vacuum passages A Feedback Control Solenoid is used to control air entry A duty cycle signal from the
93. several different sensors and actuators The system controls fuel delivery idle speed ignition timing and various emission devices EFI Electronic Fuel Injection In common usage this term applied to any system where a computer controls fuel delivery to an engine by using fuel injectors In Ford vehicle usage an EFI system is one using one injector for each cylinder The injectors are mounted in the intake manifold The injectors are fired in groups banks Usually all injectors on one side of the engine are fired together Injectors are fired individually in SFI engines see SFI definition EGO Exhaust Gas Oxygen sensor The EGO sensor is threaded into the exhaust manifold directly into the stream of the exhaust gases The ECA uses the sensor to fine tune fuel delivery The sensor generates a voltage of 0 6 to 1 1 volts when the exhaust gas is rich low oxygen content The voltage changes to 0 4 volts or less when the exhaust gas Is lean high oxygen content The sensor only operates after it reaches a temperature of 349 C 660 F EGR Exhaust Gas Recirculation The EGR system recirculates exhaust gases back into the intake manifold to reduce NOx emissions Various types of systems are in use on different vehicles Usually the ECA directly controls EGR flow but on some vehicles it may just activate a system controlled by non electronic means Vacuum controlled EGR valves are normal
94. sition Ignition timing only during this 2 minute period should be 20 degrees more than the base timing value give or take 3 degrees EXAMPLE If base timing is specified at 10 the measured value in this step should be 10 20 30 3 That is the timing should be in the range of 27 to 33 BTDC If measured timing does not meet this specification refer to vehicle service manual for procedures to check base timing and computer timing advance circuits If measured timing is OK proceed to SELF TEST PART 4 Key On Engine Running KOER Self Test 7 Turn Ignition Key to OFF Position For 1992 amp Newer Vehicles See page 14 for 1991 older vehicles 1 Turn Ignition Key OFF e Wait 10 seconds before proceeding 2 Turn off Electrical Loads e This includes radio headlights blower fans air conditioner and the like 3 Disconnect the In Line SPOUT or SAW Connector Depends upon ignition system SPOUT Spark Output SAW Spark Advance Word e This disconnects the computer advance timing signal from the ignition system e The ignition system will now operate at base engine timing e The connector is located close to the ignition module e There are 3 different styles illustrated depending upon your vehicle type WARNING The next step involves starting the engine Observe safety precautions e Always operate vehicle in a well ventilated area Do NOT inhale exhaust g
95. sition such as throttle position or EGR valve position It connects to three wires one for power one for ground and one to carry the position signal back to the computer e Switches These are either ON voltage signal to the computer or OFF no voltage signal to the computer Switches connect to two wires and tell the computer simple things such as whether or not the air conditioner is running e Signal Generator These create their own signal to tell the computer of some condition such as exhaust gas oxygen content camshaft position or intake manifold vacuum They may have one two or three wires connected to them The computer controls things with Actuators The computer can only send out electrical signals referred to as outputs Devices called actuators are powered by the computer to control things Actuator types include e Solenoids These are used to control a vacuum signal bleed air control fuel flow etc e Relays These switch high amperage power devices on and off such as electric fuel pumps or electric cooling fans e Motors Small motors are often used to control idle speed Other output signals Not all of the computer outgoing signals go to actuators Sometimes information is sent to electronic modules such as ignition or trip computer How the computer controls Fuel Delivery Operation and emission performance depend upon precise fuel control Early comp
96. stic Monitor IDM signal problem pulsewidth error between Electronic Distributorless Ignition System EDIS and Electronic Control Assembly ECA 242 Distributorless Ignition System DIS problem operating in failure mode 243 Electronic Distributorless Ignition System EDIS problem Secondary circuit failure in Coil 1 2 3 or 4 244 Cylinder Identification CID circuit failure during Cylinder Balance Test 311 Thermactor Air System problem no operation during Engine Run Self Test Bank 1 312 Thermactor Air System problem air flow misdirected during Engine Run Self Test 313 Thermactor Air System problem air flow not bypassed vented to atmosphere during Engine Run Self Test 314 Thermactor Air System inoperative during Engine Run Self Test Bank 2 with dual oxygen sensors Thermactor Air System problem inadequate air flow during cold start 316 Thermactor Air System problem inadequate air flow during hot engine low RPM 28 317 Thermactor Air System problem air flow not bypassed vented to atmosphere during Engine Run Self Test 318 Engine Air Management EAM System problem monitor circuit signal voltage is high when commanded off 319 Engine Air Management EAM System problem monitor circuit signal voltage is low when commanded on 326 Pressure Feedback EGR PFE sensor or EGR Pressure Transducer EP
97. sting purposes The connector is wired to the ECA and is located in the engine compartment Tests are run and codes are read with the Code Scanner connected Sometimes this connector is called VIP Vehicle in Process Self Test Input STI A wire between the ECA and either the Self Test connector MCU systems or a separate connector EEC IV systems The wire is used to activate the Self Test procedures The Code Scanner connects STI to vehicle ground when the Test Hold switch is in the TEST position and disconnects STI when the Test Hold switch is in the HOLD position Self Test Output STO A wire between the ECA and the Self Test connector Results of vehicle diagnostic tests are sent along this circuit by using a voltage pulse signal The signal switches between High 5 volts and Low close to zero volts The Code Scanner light is OFF when STO is High and ON when STO is Low Note the light may be on or off when the ignition key is off depends upon vehicle The flashes represent code numbers used to locate problems Sensor Device which give the ECA information The ECA can only work with electrical signals The job of the sensor is to take something the ECA needs to know such as engine temperature and convert it to an electrical signal which the ECA can understand The ECA uses sensors to measure such things as throttle position coolant temperature engine speed in
98. switches one for mid temperature and a second for high low temperatures the switch will signal when the temperature is either too high or too low The MCU module uses temperature information when controlling fuel delivery Thermactor Air System spark retard throttle kicker and canister purge CPS Crankshaft Position Sensor This crankshaft mounted sensor sends a frequency signal to the ECA See PIP signal definition It is used to reference fuel injector operation and synchronize spark plug firing on distributorless ignitions Clutch switch Cylinder Balance Test A diagnostic Self Test only used on Sequential Electronic Fuel Injector SEFI engines The test turns each injector on and off to check if they are closed or damaged DCL Data Communication Link A two wire circuit used by the ECA to exchange information with other computer controlled modules Digital Signal An electronic signal which has only two 2 voltage values a low value close to zero and a high value usually 5 volts or greater Sometimes the low voltage condition is called Off and the high voltage condition is called On Signals which can have any voltage value are called analog signals Distributorless Ignition System In general use this refers to a system which produces the ignition spark without the use of a distributor Ford technical manuals use DIS when referring to a particular dis
99. t failure 572 EGR vent solenoid circuit failure 573 Electro Drive Fan EDF operation not detected during Key On Engine Off Self Test 574 High Speed Electro Drive Fan HEDF operation not detected during Key On Engine Off Self Test 578 Variable Control Relay Module VCRM Air Conditioner Pressure sensor circuit shorted 579 Variable Control Relay Module VCRM insufficient Air Conditioner Pressure change 581 Variable Control Relay Module VCRM excessive current flow in fan circuit 582 Variable Control Relay Module VCRM open circuit failure in fan circuit 583 Variable Control Relay Module VCRM excessive current flow in fuel pump circuit 584 Variable Control Relay Module VCRM open circuit failure in module power ground circuit Variable Control Relay Module VCRM excessive current flow in Air Conditioner Clutch circuit 586 Variable Control Relay Module VCRM open circuit failure in Air Conditioner Clutch circuit 587 Variable Control Relay Module VCRM communication failure 617 Transmission problem 1 2 shift error 618 Transmission problem 2 3 shift error 619 Transmission problem 3 4 shift error 621 Transmission problem Shift Solenoid 1 SS1 circuit failure 622 Transmission problem Shift Solenoid 2 SS2 circuit failure 624 Electronic Pressure Control EPC solenoid circuit failure
100. tage power lines Electronic Pressure Control solenoid Located in certain electronically controlled transmissions Used by the ECA to set hydraulic line pressures inside the transmission for soft or firm shifting depending upon vehicle acceleration EVP EGR Valve Position sensor This sensor is mounted on top of the EGR valve lt monitors the position of the EGR valve stem that is how far the valve is open This signal allows the ECA to calculate EGR flow at any time EVR EGR Vacuum Regulator solenoid This solenoid is controlled by a duty cycle signal from the ECA and is used to vary the amount of vacuum applied to the EGR valve The solenoid not only controls the vacuum it also functions as a vent to allow the EGR valve to close The ECA controls the amount of EGR valve opening by adjusting the vacuum being applied See Duty Cycle definition FBC Feedback Carburetor This is used on early versions of computer controlled engines ltis a carburetor which can have its air fuel delivery modified by an electronic signal from the ECA Three versions are used See definitions for FBCA FCS and VRS FBCA Feedback Carburetor Actuator Used on feedback carburetors those where the engine computer controls the air fuel ratio The FBCA is a stepper motor see Stepper Motor definition It controls a metering assembly in the carburetor which can vary the amount of air entering the main discha
101. to the vehicle service manual No Codes trouble shooting chart e An engine ID code is sent after a few seconds to signal the beginning of KOER Self Test e Count flashes on the STO light 4 cylinder 2 Flashes 6 cylinder 3 Flashes 8 cylinder 4 Flashes 7 3L Diesel 5 Flashes IMPORTANT Some actions may be required at this time Vehicles with PSPS Power Steering Pressure Switch Turn steering wheel one half turn and release within 1 or 2 seconds AFTER seeing engine ID code The computer checks for switch action Vehicles with BOO Brake On Off switch when used by computer Press and release the brake pedal AFTER seeing engine ID code The computer checks for switch action Vehicles with OCS Overdrive Cancel Switch Toggle the switch on and off AFTER seeing engine ID code The computer checks for switch action 8 Perform WOT Action After Dynamic Response Signal e The Dynamic Response signal is a single flash on the STO light occurring 6 to 20 seconds after the engine ID code is sent So DYNAMIC RESPONSE e Perform a brief Wide Open Throttle WOT action right after the Dynamic Response signal Completely press and release throttle e Some vehicles do not use this signal no throttle action is necessary 9 Get Codes from the Flashing STO Light e The KOER Key On Engine Running codes are sent 4 to 15 seconds after the Dynamic Response signal There a
102. tomatic battery shut off when not in use There is no power off switch because the unit uses no power when the light is off and the tone is quiet The battery must be installed before use Installing the Battery Do the following 1 Remove two screws from the bottom side of the Code Scanner 2 Separate the two halves of the Code Scamer 3 Insert battery 4 Reassemble Code Scanner case and replace screws Checking the Battery Do the following 1 Put the Hold Test switch in TEST position Ky O A i o EL caro CODEC 4 SCANNER E EC 2 Put the Audio switch in ON position 3 Use a coin to touch the two side by side terminals on the bottom row the one with three terminals of the Code Scanner connector 4 Both the STO light and the tone should turn ON Replace battery when the light or tone gets weak Connector Location Where the Self Test connector can be found Connector Types The Code Scanner plugs into the vehicle Self Test connector which is located in the engine compartment e The EEC IV computer system most 1984 amp up vehicles uses TWO test connectors A large six sided connector A small single wire pigtail connector Both of these connectors must be plugged into the Code Scanner before use e The MCU system most 1981 1983 vehicles uses ONE test connector A large six sided connector identical to the one use
103. tributorless ignition system where the ECA directly controls timing of spark firing Compare to EDIS definition Driver A transistor switch inside the ECA used to apply power to an external device This allows the ECA to control relays solenoids and small motors Duty Cycle A term applied to frequency signals those which are constantly switching between a small voltage value close to zero anda larger value usually 5 volts or greater Duty cycle is the percentage of time the signal has a large voltage value For example if the signal is high large voltage half of the time then the duty cycle is 50 If the signal is high only one fourth of the time then the duty cycle is 25 A duty cycle of 0 means the signal is always at a low value and not changing A duty cycle of 100 means the signal is always at a high value and not changing The engine control computer uses duty cycle type signals when it wants more than just on off control of an actuator This is how it works A 50 duty cycle signal going to a vacuum switching solenoid means the solenoid will be on passing full vacuum half the time and off passing no vacuum half the time The average amount of vacuum passing through the solenoid will be one half of the full value because the solenoid is only on for one half of the time The signal switches at a rapid rate such as ten times a second
104. ttle Kicker TK solenoid circuit failure 89 Lock Up Solenoid LUS circuit failure Or Converter Clutch Override CCO solenoid circuit failure Or 25 Exhaust Heat Control EHC solenoid circuit failure 91 Exhaust Gas Oxygen EGO sensor signal voltage always indicates lean either during Engine Run Self Test rich air fuel conditions or normal engine operating conditions or Transaxle problem Shift Solenoid 1 SS1 circuit failure 92 Right side Exhaust Gas Oxygen EGO sensor signal voltage always indicates rich during Engine Run Self Test lean air fuel conditions Or Transaxle problem Shift Solenoid 2 SS2 circuit failure 93 Throttle Position TP sensor signal voltage too low during Self Test at maximum extension of idle speed control motor Or Right side Exhaust Gas Oxygen EGO sensor cool down occurred Or Transaxle problem Coast Clutch Solenoid CCS circuit failure Thermactor Air System problem on the right bank passenger side Or Transaxle problem Shift Solenoid 1 SS1 circuit failure 95 Thermactor Air System problem right passenger side air flow always upstream Or Fuel Pump Monitor FPM signal indicates circuit problem 96 Thermactor Air System problem right passenger side air flow will not bypass or Fuel Pump FP circuit failure or
105. ttle Position sensor This is a rotary type potentiometer connected to the throttle shaft lt has a voltage signal output which increases as the the throttle is opened The ECA uses this sensor to determine if the engine is in idle part throttle or wide open throttle operation Then the ECA can properly control systems such as idle speed spark advance fuel delivery and emission controls 64 TTS Transmission Temperature Switch Sends a temperature status signal to the ECA Vacuum Switch A vacuum operated electrical switch The switching action occurs when applied vacuum reaches a certain level The switches may either be normally closed or normally open These are used mainly in the MCU engine control system The switches send signals to the MCU module VAF Vane Air Flow sensor This sensor is a rotary type potentiometer connected to a moveable flap It is located inside the vane meter assembly a housing between the air cleaner and throttle body through which all incoming air passes Flowing air pushes against the flap The sensor sends a signal based on the flap position The voltage signal increases when the flap moves because of increased incoming air flow The ECA determines the amount of incoming air with this sensor This information is used for for control of fuel delivery spark advance and EGR flow VAT Vane Air Temperature sensor This sensor is a thermistor a resistor whose r
106. ture e Some MCU systems use a single electrical switch Low Temperature Switch The switch is activated by vacuum The vacuum comes from a Ported Vacuum Switch which is temperature controlled When engine temperature reaches a certain value the Ported Vacuum Switch sends vacuum to the Low Temperature Switch which toggles and sends a signal to the MCU computer The Low Temperature and Ported Vacuum switches may be separate units or combined into one assembly e Other MCU systems use two switches Mid and Dual Temperature The Mid Temperature Switch is similar to the Low Temperature Switch The Dual Temperature Switch sends a signal when engine temperature is either cold OR very hot How MCU measures Throttle Position e Some MCU systems use an Idle Tracking Switch This is an electrical switch mounted near the throttle linkage on the carburetor The switch is open when the throttle is resting in idle position The switch closes as soon as the throttle is moved off idle A Wide Open Throttle WOT Vacuum Switch is also used Weak manifold vacuum due to WOT operation causes the WOT Vacuum Switch to send a signal to the MCU computer e Other versions of MCU monitor engine vacuum to sense idle high vacuum cruise moderate vacuum or WOT low vacuum conditions Vacuum operated electrical switches are used The switches toggle at various vacuum levels and send signals to the MCU computer These parts are sometime
107. u turned on a wall switch in your home and the ceiling light did not turn on Is it a bad bulb or light socket Is the bulb installed correctly Are there problems with the wiring or wall switch Maybe there is no power coming into the house As you can see there are many possible causes The diagnostics written for servicing a particular trouble code take into account all the possibilities If you follow these procedures you should be able to find the problem causing the code and fix it if you want to do it yourself Actron makes it easy to fix computer controlled vehicles Using the Actron Code Scanner to obtain trouble codes is fast and easy Trouble codes give you valuable trouble codes are and where they come knowledge whether you go for from you are well on your way to fixing professional vehicle servicing or do it today s computer controlled vehicles yourself Now that you know what Vehicle Service Information The following is a list of publishers who have manuals containing trouble code repair procedures and related information Some manuals may be available at auto parts stores or your local public library For others you need to write for availability and prices specifying the make style and model year of your vehicle Vehicle Service Manuals Vehicle Service Manuals from Ford Chilton Book Co Motor Company Ford Lincoln Chilton Way Mercury Radnor PA 19089 Ford Publication Department Helm I
108. uel Evaporation Recovery System A special canister collects vapors evaporating from the fuel tank preventing them from escaping into the atmosphere and causing pollution During warm engine cruise conditions the computer draws the trapped vapors into the engine for burning See CANP in Reference Glossary Other computer functions The computer controls other odd jobs like handling speed control and transmission torque convertor lock up and shifting functions Detailed explanations may be found in your 94 vehicle service manual More information The Reference Glossary describes the various sensors and actuators used in the EEC IV and MCU systems You can learn more by reading these definitions THE MCU SYSTEM Make sure you have read everything in the beginning part of this section before continuing The MCU system is similar but simpler than the EEC IV version just described The MCU computer module is located in the engine compartment The MCU uses sensors to monitor engine operation and actuators to control things What MCU controls The original MCU just controls fuel delivery Air Fuel ratio and the Thermactor Air System Features added later included limited control of idle speed spark timing retard and fuel evaporation canister To do these tasks the MCU needs information about engine temperature throttle position tach signal and knock conditions How MCU measures Engine Tempera
109. um and sends a frequency signal to the ECA This gives the ECA information on engine load for control of fuel delivery spark advance and EGR flow MCCA Message Center Control Assembly A dashboard mounted electronic display giving the driver trip computer and vehicle status information Exchanges information with the ECA by using the Data Communications Link DCL MCU Microprocessor Control Unit A computerized engine control module used on many Ford vehicles between 1980 and 1984 The MCU system consists of a computerized control module MCU sensors and actuators The system controls fuel delivery and thermactor air flow Later versions of MCU also controlled canister purge see CANP definition spark retard and idle speed The MCU system was eventually replaced by EEC IV MLP Manual Lever Position sensor Connected to gear shift lever Sends a voltage signal to the ECA indicating lever position P R N D 2 or 1 Mode A type of operating condition such as idle mode or cruise mode NDS Neutral Drive Switch Used on vehicles with automatic transmissions The ECA uses this switch to determine when the transmission is in or out of gear The ECA can adjust idle speed to compensate for increased engine loading due to engaged transmission NGS Neutral Gear Switch Used on vehicles with manual transmissions The ECA uses this switch to determine when the transmission is in o
110. use FLASH FLAS F NZ TES Av PAUSE AO ay FLASH pause FLASH FLASH longer pause LASH FLASH pause LASH FLASH 5 Turn Ignition Key to OFF Position At this point you can either e Have your vehicle professionally serviced Codes indicate problems found by the computer or e Repair the vehicle yourself using service codes to help pinpoint the problem Refer to Test Results Chart Key On Engine Off KOEO Test Results KOEO CODES 11 all except high altitude 62 high altitude V 6 or V 8 ONLY 65 high altitude l 4 ONLY Any Code s No Codes Received STO light always on or off ACTION TO TAKE System pass No problem found by computer during KOEO Self Test Go to SELF TEST PART 3 Key On Engine Running KOER Self Test System pass No problem found by computer during KOEO Self Test Go to SELF TEST PART 3 Key On Engine Running KOER Self Test System pass No problem found by computer during KOEO Self Test Go to SELF TEST PART 3 Key On Engine Running KOER Self Test Codes indicate system problems are present now Write down all codes Refer to vehicle service manual for code troubleshooting charts and repair procedures Repeat PART 2 Key On Engine Off KOEO Self Test after every repair Do not proceed to SELF TEST PART 3 until a system pass code is received You have a problem which must be repaired before proceeding Refer to the vehicle service manual
111. uter controlled vehicles used electronically adjustable carburetors but fuel injectors were soon introduced The job of the computer is to provide the optimum mixture of air and fuel air fuel ratio to the engine for best performance under all operating conditions The computer needs to know what the engine operating condition is Sensors used coolant tempera ture throttle position manifold absolute pressure mass air flow RPM e how much air is coming into the engine Sensors used mass air flow or a combination of manifold absolute pressure manifold air temperature RPM e how much fuel is being delivered The computer knows this by how long it turns on the fuel injectors The computer uses a feedback control or duty cycle solenoid on electronic controlled carburetors e that everything is working the way it should Sensor used exhaust gas oxygen sensor Note Not all engines use every sensor listed above Cold engine warm up condition Open Loop operation The coolant temperature sensor tells the computer how warm the engine is Factory engineers know what the best air fuel mixture is for the engine at various operating temperatures More fuel is needed for a cold engine This information is permanently programmed into the computer After the computer knows the engine temperature it determines the amount of air coming in then it will look at its programming to find out how
112. vehicle service manual for troubleshooting charts related to e Connect the Code Scanner to i the vehicle symptom BOTH test connectors the small single wire connector and the larger 6 sided one Note One Code Scanner pin plugs into an unused position on large test connector This is normal Also large test connector may have other contacts not used by Code Scanner e The Code Scanner will not harm the vehicle engine computer 12 Self Test Part 2 Key On Engine Off KOEO Self Test IMPORTANT You must complete all steps in Self Test Part 1 before proceeding to Part 2 Verify good battery in Code Scanner Section 2 1 Verify Ignition Key is in OFF Position 2 Put Code Scanner HOLD TEST Switch in HOLD Position e Do the following also CP9015 Ford Lincoln amp Mercury Domestic 19818 Newer For 4 9L only depress clutch until Step 5 codes sent For 7 3L diesel only completely depress throttle until Step 5 codes sent For 2 3L turbo with octane switch put switch in premium position 3 Turn Ignition Key to ON Position but DO NOT START THE ENGINE 4 Put Code Scanner HOLD TEST Switch in TEST Position e This starts the KOEO Self Test e Testing takes anywhere from 10 seconds to one minute before codes are sent e You may hear clicking sounds in the engine compartment as relays are being tested WARNING Stay away from the radiator cooling fan It may tur
113. work with electrical signals The job of the sensor is to take something the computer needs to know such as engine temperature and convert it to an electrical signal which the computer can understand You can think of sensors as high tech senders the devices found in older vehicles for gauges and dashboard message lights BRAINS OF THE COMPUTER oil pressure fuel level etc Signals running into the computer are referred to as inputs Sensors monitor such things as e Engine temperature e Intake manifold vacuum e Throttle position e RPM e Incoming air temperature amount e Exhaust gas oxygen content e EGR Valve flow Most engine computer systems will use the sensor types listed above Additional sensors may be used depending upon the engine vehicle type or other tasks the computer must do Note that information from one sensor may be used by the computer for many different tasks For example engine temperature is something the computer needs to know when controlling fuel delivery spark timing idle speed and emission systems The sensor information may be very important for one engine control function but only used to fine tune a second one There are several types of sensors e Thermistor This is a resistor whose resistance changes with temperature It is used to measure temperatures of coolant or incoming air It has two wires connected to it e Potentiometer This signals a po
114. y cycle type signal See Duty Cycle definition It is used for idle speed control The valve operates by regulating the amount of incoming air bypassing the closed throttle plate When the ECA increases control signal duty cycle more air is bypassed through the valve for faster idle speed The ECA determines the desired idle speed by looking at coolant temperature engine load and RPM The ISC BPA also performs dashpot and anti dieseling functions ITS Idle Tracking Switch This is amechanical switch built into the tip of the Idle Speed Control motor spindle See ISC definition The ECA uses this switch to identify closed throttle condition The switch is open when the throttle rests on it closed throttle position The MCU systems use a similar acting ITS which is mounted on the carburetor near the throttle linkage IVSC Integrated Vehicle Speed Control The name given to the speed control function when it is built into the ECA and not controlled by an outside module KAPWR Keep Alive Power A power connection running from the ECA directly to the vehicle battery This power is used energize the learning memory circuits inside the ECA even when the ignition key is off The memory stores adjustment information the ECA uses to compensate for aging sensors and the like The information is lost when power is disconnected such as when the vehicle battery is removed for service but can be re

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