PDI 890 - PDIMeters
Contents
1. Connect the Current Clamp around the negative or posi tive battery cable Set the rotary switch to the Voltage setting Note 1mV 1 Amp Make sure all vehicle accesso ries are truned OFF Start the engine and hold at 1500 RPM The amperage reading should be 5 amps or better Note The current clamp measures amps in the direction of electrical flow Make sure the arrow on the clamp is pointed in the direction of the current flow in the cable Quick Test Place the clamp on the battery cable then turn the headlights on If the reading is not negative disconnect the clamp turn it over and reconnect 36 Basic Diagnostic Testing Ignition System Tests 1 Ignition Coil Primary Resistance Test Q This test checks primary winding resistance Important Test the ignition coil cold and hot Set the rotary switch to the Resistance Q setting Insert Black lead in COM terminal Red lead in V Q RPM terminal Disconnect the coil from the vehicle wiring harness Note The resistance in the meter leads rnust be subtracted to get an acccurate measurement at the 1 0 2 0 range Connect the negative lead to the negative terminal on the coil Connect the positive lead to the positive B terminal on the coil Typical measurements are be tween 1 0 2 0 22 s Consult the manufacturer s specifications for required resistance measure GM DIS C2. Wrong range selected e Blown fuse 4 Meter readings do not change e Hold feature is still toggled ON 21 Basic Diagnostic Testing This chapter leads you through a systematic series of tests that check the vehicle electrical system These tests should be performed before testing individual components AUTOMOTIVE METER DRPM 22 Basic Diagnostic Testing Electrical System Diagnostics Itis important to diagnose a vehicle electrical problem thoroughly and efficiently The series of tests that follow check primary areas that are respon sible for the majority of the electrical problems found in an automobile Perform these basic tests first even if a vehicle has a trouble code set in the computer A component malfunction detected by the computer can be caused by a basic ground problem in the electrical system Simply replacing a failed component will not fix the problem if a poor grond caused the component failure The tests begin by checking the main source of power and the chassis ground circuit connections Ground circuits are one of the least understood but potentially most troublesome areas of automotive electronics An excessive voltage drop in a ground circuit effects the entire electrical circuit This is why it is important to make sure the basic circuits are in good shape before checking trouble codes and components Basic Diagnostic Testing Battery Testing 1 Ba
3. 10Amp measurement for 60 seconds maximun 1 Ohms can not be measured if voltage is present ohms can be measured only in a non powered circuit However the meter is protected to 500 volts Duty Cycle Dwell angle Getting Started This chapter will help you get started It describes the basic functions of the Meter AUTOMOTIVE METER Getting Started Meter Basics 1 Digital and Analog display Dispaly features a Four character digital dispaly b Symbols to identify function c Analog bar graph The digital display is best for stable input The bar graph is best for rapidly changing input 2 Function buttons Press the button to select a func tion A symbol will display to verify your choice 3 Rotary Selector Switch Turn this switch to select a func tion or turn the meter OFF 4 Temperature Terminal Insert the temperature probe in this terminal 5 Test Lead Terminals The Black test lead is used in the Common COM terminal for all tests The Red test lead is used to measure Amps or Volts 5 Black 5 Red Getting Started Meter Basics Cont d Digital and Analog dispaly When DWELL of cylinders is selected with the rotary switch Low Battery Replace the meter battery when this symbol displays Diode test Continuity test 100000000000000000000000000000000 gt Press HOLD to hold data display or resume t
4. Connect the positive lead to the positive battery termi nal Connect the negative lead to the positive terminal on the starter soleniod Disable the ignition so the en gine doesn t start crank the engine for 2 3 seconds The example shown has 2 con nectors and 1 wire A voltage drop of more than 0 3 volts would indicate a poor circuit Clean and inspect the battery cables and cable connections test again Starter Solenold Important Repeat this test when the engine is thoroughly warmed up Heat expansion of metal causes resistance to increase 31 Basic Diagnostic Testing Voltage Drop Testing Cont d 4 Battery Power to Complete Starter Circuit This test checks battery power efficiency to the starter through the starter soleniod e Set the rotary switch to voltage e Establish the base voltage that you will compare test voltage against see base voltage Volt Drop Test 1 e Connect the positive lead to the battery terminal e Connect the negative lead to the positive terminal on the starter motor e Disable the ignition so the en gine doesn t start crank the engine for 2 3 seconds The example shown has 4 con nectors 2 wires and 2 solenoid connections A voltage drop of more than O 8 volts would indi cate a poor circuit Clean and inspect the battery and starter cab
5. connec tion switch solenoid and the complete circuit should be tested Each connection point is a potential source of in creased resistance Maximum Voltage Drop Maximum voltage drop should not be more than 0 1 volt per wire ground connection switch or solenoid Wire 0 1V Connectlon 0 1V Max Connectlon 0 1V Max Total resistance should be no more than 0 4V Max for the example shown 28 Basic Diagnostic Testing Voltage Drop Testing 1 Negative Engine Ground This testchecks for engine ground efficiency Set the rotary switch to Volt age Touch the positive lead to the positive battery post and the negative lead to the negative battery post Note the reading this will be the base voltage to compare your test voltage reading against Connect the positive lead to aclean spot on the engine block Connect the negative lead to the negative battery post Disable the ignition so the en gine doesn t start crank the engine for 2 3 seconds The example shown has 2 con nectors 1 wire 1 ground and 1 terminal to battery post A volt age drop of more than 0 5 volts would indicate a poor ground cir cuit Clean and inspect the battery cable connections and the around test again Important Repeat this test when the engine is thoroughly warmed up Heat expansion of metal may cause resistance to increase 29
6. Diagnostic Testing Ignition System Tests Cont d 4 Distributor Cap Rotor Resistance Test This test checks for open circuits or hight resistance in the distribu tor cap and rotor Set the rotary switch to the Resistance Q Insert Black lead in COM terminal Red Jead in V Q RPM terminal Dist Cap Center Connector Test Connect the test probes to oppo site ends of the distributor cap terminal see illustration In general resistance 2 should be 5K 10K Refer to the Manufacturer s specifications Rotor Test Connect the test probes to oppo site ends of the rotor contacts see illustration In general resistance should be 0 1 Q or less Refer to the Manufacturer s specifications Black 40 Basic Diagnostic Testing Ignition System Tests Cont d 5 Pick up Coil Resistance Q Voltage Test V The Resistance test checks for open circuits or high resistance The Voltage test compares volt age output to resistance Test Procedure Set the rotary switch to the Resistance Insert Black lead in COM terminal Red lead in V Q RPM terminal Connect the test probes to the pick up coil leads see illus Resistance Specifications The majority of the pick up coils will test between 500 1500 22 s resistance See manufacturer s specification for required range Set rotary switch to Volts Press the Alternate Function button to
7. Electrical Specifications ELECTRICAL SPECIFICATIONS Accuracy is given as of reading number of least significant digits at 18 C to 28 C 65 F to 83 F with relative humidity up to 7096 RPM Tach Ranges 600 3200 3200 12000 x10 RPM Resolution 1 RPM Effect Reading gt 600 RPM Accuracy 2 rdg 4dgts Overload protection 500 VDC or RMS AC DUTY CYCLE Range 1 096 90 0 Resolution 0 1 Pulse width 100ys 100ms Accuracy 2 096 rdg 5 dgts Overload protection 500 VDC or RMS AC DWELL ANGLE No of cylinders 4 5 6 8 Ranges 0 90 0 4 CYL 0 72 0 5 0 600 6 CYL 0 45 0 8 CYL Resolution 0 1 Accuracy 2 0 rdg 5 dgts Overload protection 500 VDC or RMS AC TEMPERATURE Ranges 20 to 750 C 4 to 14007 F Resolution 1 C 1 F Accuracy 3 0 rdg 2 C 3 0 rdg 4 F Sensor Type K Thermocouple Input protection 60VDC or 24VAC rms 60 Specifications Electrical Specifications Cont d DC VOLTAGE Autoranging Ranges 320mV 3 2V 32V 320V 600V Resolution 100V Accuracy 1 2 rdg 1dgt Input impedance 10MQ Overload protection 600VDC or AC rms AC VOLTAGE Autoranging Ranges 3 2V 32V 320V 600V Resolution 1mV Accuracy 2 0 rdg 4dgts at 50Hz to 60Hz Input impedance 10MQ Overload protection 600VDC or AC rms CURRENT Ranges 320pA 3200pA 32mA 320mA 10A Resolution 0 1pA DC Accuracy 2 0 rdg 1dg
8. the rotary switch Press the Alternate Function button to select Diode check Insert Black lead in COM terminal e Red lead in V Q RPM terminal Touch the Black test probe to the negative side of the diode Touch the Red test probe to the positive side of the diode Reverse the probes Black to the positive side and Red to the negative side Note A good diode will read low in one direction and high in the other direc tion when the probes are reversed A gefective diode will have the same reading in both directions or read between 1 0 to 3 0 Vor OL over limited in both directions Reverse Probes Diode to T to Bad 4 to 0 9V OL OL 0 to 3 0V 0 4 to 0 9V 000V Getting Started Meter Functions Temperature 9 IMPORTANT To avoid heat dam age to the meter keep it away from sources of very high tem perature The life of the tempera ture probe is also reduced when subjected to very high tempera tures operating range is 4 to 1 400 F Select desired temperature unit of measurement 9 C F with the rotary switch nsert the temperature probe connector into the K type ther mocouple socket Touch the end of the temperature sensor to the area or surface of the object to be measured Temperature Probe Temperature Sensor Getting Started Meter Functions Frequency Hz Set the rotary s
9. 2 wire Tests Many components that regulate temperature can be tested by measuring the surface tempera ture of the area surrounding the component Connect the temperature probe to the meter e Set the rotary switch to the Temperature range you desired to be measured e Touch the end of the tempera ture probe directly to the sur face of the component to be tested Compare your readings with the manufacturers specifications The temperature should be within 10 F 5 C of thedatastream values Some of the components that can be tested for temperature varia tion are e Radiators e Transmission e Heaters e A C Condensers e A C Evaporators e Engine Coolant Sensors e Coolant Temperature Switches e Air Temperature Sensors 49 Thermistors are variable resistors that are sensitive to temperature level changes As the temperature changes the thermistor s resis tance value changes Select the Ohms range with the rotary switch e Connect the test probes to the sensor terminals The Ohms reading should match the temperature of the sensor see manufacturer s specifica tions Black Typical thermistor applications are e Engine Coolant Temp ECT e Air Charge Temp ACT e Manifold Air Temp MAT e Vane Air Temp VAT e Throttle Body Temp TBT 50 Basic Component Testing Component Tests Input Cont d Thermistor Variable Resista
10. Basic Diagnostic Testing Voltage Drop Testing Cont d 2 Negative Chassis Ground This test checks for chassis ground efficiency Set the rotary switch to Volt age Establish the base voltage that you will compare test voltage against see base voltage Volt Drop Test 1 s Connect the positive lead to the point on the fender fire wall or vehicle frame where the ac cessory ground is fastened Connect the lead to the negative battery terminal Turn all of the accessories ON bright lights A C fan high rear window defroster wind shield wipers etc Disable the ignition so the en gine doesn t start crank the engine for 2 3 seconds The example shown has 2 con nectors 1 wire 1 ground and 1 terminal to battery post A volt age drop of more than 0 5 volts would indicate a poor ground cir cuit Clean and inspect the battery cable connections and the ground test again Black Important Repeat this test when the engine is thoroughly warmed up Heat expansion of metal may cause resistance to increase 30 Basic Diagnostic Testing Voltage Drop Testing Cont d 3 Battery Power to Starter Solenoid This test checks battery source effieciency to the starter sole noid e Set the rotary switch to Volt age Establish the base voltage that you will compare test voltage against see base voltage Volt Drop Test 1
11. COMPREHENSIVE INSTRUCTION MANUAL AUTOMOTIVE METER aV VORPM 2 5 6 AUTOMOTIVE MULTIMETER Complete step by step electrical systems troubleshooting guide included DISCLAIMER This manual tells you how to use the meter to perform diagnostic tests and to find possible locations of vehicle problems It does NOT tell you how to correct the problems All information illustrations and specifications contained in this technical manual are based on the latest information available at the time of publication The right is reserved to make changes at any time without notice SAFETY The instrument complies with class 11 overvoltage CAT III of the IEC1010 1 EN61010 1 standard If the equipment is used in a manner not specified the protection provided by the equipment may be impaired A 5 When servicing use only specified replacement parts or equivalent The symbols used on this instrument are 4 Caution risk of electric shock A Caution refer to accompanying documents B Equipment protected throughout by Double insulation Class 11 Alternating current Direct current Ground This product complies with the requirements of the following Eu ropean Community Directives 89 336 EEC Electromagnetic Com patibility and 73 23 EEC Low Voltage as amended by 93 68 EEC CE Marking However electrical noise or intense electromagnetic fields in the vicinity of the equip ment may disturb th
12. al will be in one of three configurations ON or OFF only switch Check for continuity with the switch in TU the ON and OFF position Switch Duty Cycle Mixture Control Solenoid Measure the percent of high or low time in a duty cycle In most cases the low time is the ON time Mixture Control Solenoid 58 Specifications General Specifications GENERAL SPECIFICATIONS Display 3 digit 3200 counts liquid crystal display LCD with function and units sign annunciators Analog Bar Graph 34 segments with measurements 12 times per second Polarity Automatic negative polarity indication Overrange Indication OL mark indication Low Baattery Indication The 3 is displayed when the battery voltage drops below the operating level Measurement Rate 2 times per second nominal Operating Environment 0 C 50 C 32 F to 122 F at lt 70 R H Storage Environment 20 C to 60 C 4 F to 140 F at 80 R H Temperature Coefficient 0 2 x specified accuracy lt 18 C or gt 28 C Power Single standard 9 Volt battery NEDA 1604 or IEC 6F22 Battery Life 200 hours typical with alkaline battery Fuse 10A 600V 6 3x25mm fast acting ceramic type 0 5A 250V 5x20mm fast acting ceramic type Dimensions 147mm x 70mm Wi x 39mm D Weight Approx 222g Meter Only 355g With Holster 59 Specifications
13. des for faults that have occurred in the past DESCRIPTION 02 SENSOR CIRCUIT COOLANT TEMP HI COOLANT SENS LO TMP TPS VOLTAGE HI TPS VOLTAGE LOW MANIFOLD AIR TEMP HI VSS LOW MANIFOLD AIR TEMP LO Failure Codes When a failure is detected by the computer it stores the informa tion in the form of Fault Codes also known as Trouble Codes or Service Codes These Fault Codes are usually a two or three digit number that identifies the electri 32 EGR VACUUM ERROR cal circuit effected Once these 22 SENSOR nag codes have been read the vehicle iai VLINDER SELECT EBR R repair can be started Be sure to EST GROUNDED closely follow the vehicle service OS SENSOR LEAN manual diagnostic precedures 02 SENSOR RIGH repairs and specifications PROM ERROR Note Typical codes are shown as examples only 46 Basic Component Testing Basic Component Testing Computer Controlled Systems Cont d Computer Controlled Systems Cont d Component Testing Duty Cycle What is it Component testing with a meter generally requires detailed schemat ics and specifications that are provided by the manufacturer The following section provides general information for the main groups of sensors input devices and actuators output devices Duty Cycle is the percentage of time a voltage is positive campared to negative ON com pared to OFF For example duty cycle measurements are used for Positive The primary in
14. e measurement circuit Measuring instruments will also respond to unwanted signals that may be present within the measurement circuit Users should exercise care and take appropriate precautions to avoid misleading results when mak ing measurements in the presence of electromagnetic interference SS Introduction About This Manual Chapter Introduction Getting Started Basic Diagnostic Testing Basic Component Testing Specifications Description Table of Contents Safety Warnings Meter Basics Meter Functions e Maintenance Battery Testing Voltage Drop Testing Starter Motor Testing Charging System Testing gnition System Testing Computer Controlled Systems Component Tests Input e Component Tests Output General Specifications Electrical Specifications Introduction Contents Introduction cee ee eee Hmm 1 ECCE 2 Getting Started se 5 Meter Basics se Hem Henne 6 Digital and Analog display eH 7 Function and Range Select see 8 Push button Functions eene mH 9 Alternate Function mee 9 Range Select eem 9 Data Hold Hold mme 9 Meter Functions Voltage eein eene detener nnne t 10 RESISTANCE siuii eene nnnm enne tenente eto 11 Audible Continuity m 12 Diode Chetki tetas en reco Pese Pra ry 13 Temperature emen 14 Frequenc
15. ead to the positive 4 battery termi nal Connect the negative lead to the negative battery termi nal Disable the ignition crank the engine for 15 seconds Check the display A reading of less than 9 60V 9 70 F indicates a weak battery Recharge replace before testing VOLTAGE LOAD TEST Reading Temperature SV 7O E219C 92V 9 2V 50 F 10 C 30 F 1 C 20 F 7 C Black Note For each 10 above or below 70 add or subtract 0 1 volt Battery temperature can be checked with the meter temperature probe 27 Basic Diagnostic Testing Voltage Drop Testing Resistance What is it Resistance is an opposing force created by a circuit or compo nent to the flow of electrical current There is a small amount of natural resistance when voltage flows through wires switches grounds or connections The resistance increases beyond acceptable lim its if corrosion develops fittings become loose or wires fray Re sistance increases each time something such as wire a switch connections or the ground are added in the circuit Voltage Drop What is it Voltage drop is the difference in voltage potential when measured across a circuit or component creating resistance The resistance decreases the amount of voltage available The bulb will not light or the motor will not turn if the voltage is too low What Should be Tested Each wire ground
16. ed by the vehicle computer to determine postion and direction of movement of a device within the component Resistance Select the Ohms range with the rotary switch Disconnect the sensor Connect the test probes to the Signal Line and to the Ground refer to manufacturer s sche matic Watch the bar graph display the Ohms reading should change as the signal arm on the potentiom eter is moved signal sweep Typical potentiometer applications are Throttle position Sensor TPS Exhaust Gas Recirculation valve position sensor EVP Vane Air Flow Meter VAF Black 53 Basic Component Testing Component Tests Input Cont d Potentiometers Variable Resistance 3 wire Tests Reference Voltage Test Disconnect the vehicle wiring harness at the sensor Select the Voltage range with the rotatry switch Insert Black lead in COM terminal Red lead in V Q RPM terminal Connect the test probes in par allel Positive to the com puter reference voltage circuit negative to the negative sys tem ground circuit from the sen sor Turn the ignition switch ON do not start the engine Watch the bar graph display Read ing should be 5 9 volts check the manufacturer s specifica tions 54 Basic Component Testing Basic Component Testing Component Tests Input Cont d Component Tests Input Cont d Potenti
17. ence of voltage or current make sure the meter is functioning correctly Take a reading of a known voltage or current before accepting a zero reading Choose the proper range and function for the measurement Do not try voltage or current measurements that may exceed the ratings marked on the Function Range switch or terminal When measuring current connect the meter in series with the load Never connect more than one set of test leads to the meter e Disconnect the live test lead before disconnecting the common test lead The mA and the 10A terminals are protected by fuses To avoid possible injury or damage use only in circuits limited to 320mA or 10A for 60 seconds See also Fuse Replacement Introduction Safety Cont d IMPORTANT To maintain accuracy of the meter replace the discharged battery immediately when the battery symbol appears on the meter display Avoid measuring error from outside interference keep the meter away from spark plug or coil wires Avoid damaging the meter when testing voltage Disconnect the test leads from the test points before changing functions Do not exceed the limits shown in the table below Terminal _Inputlimit _ AC Vol 600vACHmms olts VIO RPM 600VAC rms DC Volts 600VDC Frequency V Q RPM 500V AC DC Diode AC DC pA mA 320mA AC DC AC DC 10A 0 10AAC DC V Q RPM 500V AC DC
18. esting Analog bar Graph display with polarity Press RANGE button to manually select a range Negative Polarity Indicator Press Alt Function button to select Alternatiing Current Units of measure AC or Direct Current DC dwell degrees duty percent milli m 1 1 000 volts V mega M 1 000 000 kilo k 1 000 ohms 9 Hertz Hz Getting Started Meter Basics Cont d Function and Range Select Turn the rotary swich in either direction to select a function The Range is automatically se RANGE HOLD 0 od c lected by the meter But you can also select a range within a func tion by pressing the range button Always select a range higher than you expect the current or voltage to be Then select a lower range if better accuracy is needed e f the range is too high the readings are less accurate If the range is too low the meter shows OL over limit Getting Started Push button Functions Alternate Function Button Press the Alternate Function but ton to toggle between DC and AC in the voltage and current mea surements Press the button to toggle to the resistance audible and diode modes if the rotary switch is set to Qn position Range Select The range is automatically se lected by the meter But you can also manually select a range within a function by pressing the RANGE button Range Exit To exit the RANGE mode and ret
19. h is odorless causes slower reaction time and can lead to serious injury When the engine is operating keep service areas WELL VENTI LATED or attach the vehicle exhaust system to the shop exhaust removal system This chapter covers brief introductory information and safety precautions AUTOMOTIVE METER Set the parking brake and block the wheels before testing or repairing the vehicle It is especially important to block the wheels on front wheel drive vehicles The parking brake RANGE HOLD does not hold the drive wheels Wear an eye shield when testing or repairing vehicles Exceeding the limits of this meter is dangerous It will expose you to serious or possibly fatal injury Carefully read and understand the cau tions and the specification limits of this meter Voltage between any terminal and ground must not exceed 600V DC or AC e Use caution when measuring voltage above 25VAC or DC e Circuit tested must be protected by a 10A fuse or circuit breaker Do not use the meter if it has been damaged Do not use the test leads if the insulation is damaged or if metal is exposed Use current clamps to measure circuits exceeding 10A Introduction Safety Cont d A Danger Avoid electrical shock Do not e touch the test leads tips or the circuit being tested Do not try a voltage measure ment with the test leads in the 10A or the mA terminal e When testing for the pres
20. ion for a mixture con trol solenoid is shown with the metering rod in the closed posi tion To ECM Getting Started Meter Functions Dwell Select desired Dwell range with the rotary switch Insert Black lead in COM terminal Red lead in V O RPM terminal Connect the Black test probe to ground Connect the Red test probe to the wire that connects to the breaker points see illustration Black 18 Getting Started Meter Functions AC or DC Current A IMPORTANT All current mea sured flows through the meter It is important that you do not Measure current greater than 600 Volts AC or DC with re spect to ground Exceed 60 seconds when mea suring continuous current be tween 1A 10A Allow five minutes for cool down before continuing Select the 10A mA or pA range with the rotary switch Press the Alternate Function button to select AC or DC Insert Black lead in COM terminal Red lead in the 10A or mA terminal select 10A if you are unsure of the current draw IMPORTANT Turn OFF all power to the circuit or disconnect the circuit from the power source Connect The Red probe to the side of the circuit closest to the power source The Black probe to the side of the circuit to ground Turn the power ON and test 19 Note Current must always be mea
21. les soleniod and cable connections test again Note A defective starter solenoid may cause an excessive voltage drop check the cables and connections before re placing the soleniod Important Repeat this test when the engine is thoroughly warmed up Heat expansion of metal causes resistance to increase 32 Basic Diagnostic Testing Starter Motor Testing 1 Starter Current The Bettery tests and the Voltage Drop tests have verified that there is adequate battery voltage at the starter Next check for excessive starter motor current draw Connecta Current Clamp around the negative or positive battery cable Set the rotary switch to the Voltage setting Note 1mV 1Amp Disable the ignition so the en gine doesn t start crank the engine for 2 3 seconds Note The current clamp measures amps in the direction of electrical flow Make sure the arrow on the clamp is pointed in the direction of the current flow in the cable Quick Test Turn the ignition and all accessories OFF Place the clamp on the battery cable then turn the headlights on If the reading is not negative discon nect the clamp turn it over and recon nect Approximate Amperage Draw 4 Cyl 150 180 Amp Maximum 6 8 Cyl under 300 CID 180 210 Amp Maximum 6 8 Cyl over 300 CID 250 Amp Maximum 33 Basic Diagnostic Testing Charging System Tests 1 Battery This
22. mp A or Milliampere mA terminal you may be injured or the meter damaged 10 Getting Started Meter Functions Resistance Q IMPORTANT If you are testing an application that has capacitors in the circuit be sure to turn the power OFF on the test circuit and discharge all capacitors Accu rate measurement is not possible if external or residual voltage is present Select the resistance Q set ting with the rotary switch Select the resistance range with the button labeled RANGE if a more accurate measurement is desired Insert Black lead in COM terminal Red lead in V Q RPM terminal Touchthe testlead probes across the resistor to be tested 11 Getting Started Meter Functions Audible Continuity 14 IMPORTANT Tum the power OFF on the test circuit Select the Audible Continuity 4 range with the rotary switch Press the Alternate Function button to select Audible Con tinuity Insert Black lead in COM terminal Red lead in V C RPM terminal Connect one test probe to each end of the circuit to be tested Circuit complete the meter will beep Circuit open there is and the display shows OL over limit 12 Circuit complete beep sounds Getting Started Meter Functions Diode Check gt IMPORTANT Tum the power OFF to the test circuit Select the Diode Check gt setting with
23. nce 2 wire Tests Con t Voltage Presence Disconnect the vehicle wiring harness at the sensor Select the Voltage range with the rotary switch Insert Black lead in COM terminal Red lead in V O RPM terminal Connect the test probes in par allel Positive to the circuit coming from the power source negative to the negative cir cuit from the sensor Turn the ignition switch ON do not start the engine Measurement should be 5 9 Black volts check the manufacturer s specifications 51 Basic Component Testing Component Tests Input Cont d Thermistor Variable Resistance 2 wire Tests Con t Voltage Change Connect jumper wires between the connector and the sensor Connect the test probes in par allel Positive to the circuit coming from the power source negative to the negative cir cuit from the sensor Start the engine The voltage should change as the temperature changes This is the signal that is sent to the Black computer for processing Refer to the manufacturer s specifications If the voltage change is not within specifica tions look for sources of resistance due to poor connec tors connections or breaks in the wiring 52 Basic Component Testing Component Tests Input Cont d 3 Potentiometers Variable Resistance 3 wire Tests The potentiometer is a variable resistor The signal it generates is us
24. nts commonly found in a computer controlled automotive system The test procedures are due to the complexity of components general theory tests Be sure to consult the vehicle service manual for component schematics and test specifications AUTOMOTIVE METER 43 Basic Component Testing Computer Controlled Systems A need for better fuel economy and lower emissions resulted in today s automobiles utilizing computer controlled functions that were previously activated by mechanical electrical and vacuum devices Computerized vehicle control systems are made up of three basic component groups These groups are 1 Sensors they are input devices that supply information about engine operating conditions and the surrounding environment to the vehicle computer 2 Engine Control Module a vehicle computer that processes the information supplied by the sensors then sends an electronic command to the appropriate component actuators 3 Actuators these are output devices that may be electrical mechanical or vacuum components controlled by the vehicle computer Typical Sensors Coolant Vacuum Throttle RPM Barometric Oxygen Sensor Sensor Position Sensor Sensor Sensor Vehicle Computer Electro Purge Mechanical Ignition Exhaust Gas Carburetor Spark Recirculating Fuel Injection Advance Valve Typical Actuators Torque Converter Clutch 44 Basic Component Testing Compute
25. oil ments Type II Both primaries located on back of coil 37 Basic Diagnostic Testing Ignition System Tests Cont d 2 Ignition Coil Secondary Resistance Test This test checks secondary wind ing resistance Important Test the ignition coil cold and hot Set the rotary switch to the Resistance setting Insert Black lead in COM terminal Red lead in V YRPM terminal Disconnect the coil from the vehicle wiring harness Connect the negative lead to the high tension terminal on the coil Connect the positive lead to Red the positive B terminal on the coil Typical measurements are between 6 000 30 000 Q s Consult the manufacturer s specifications for required resistance measurements GM DIS Coil TYPE II 38 Basic Diagnostic Testing Ignition System Tests Cont d 3 Secondary Ignition Wire Resistance Test This test checks for open circuits or high resistance in the second ary sparkplug wires Important Twist and bend the sparkplug wire while measuring the resistance for this test Set the rotary switch to the Resistance Insert Black lead in COM terminal Red lead in V Q RPM terminal Connect the test probes to op posite ends of the sparkplug wire Typical measurements are ap proximately 1 000 22 s per inch of wire For example 10 inch cable 10 0000 39 Black Basic
26. ometers Variable Resistance 3 wire Tests 4 Oxygen Sensor O2 Test Voltage Change MID The Oxygen Sensor samples the amount of Oxygen in the exhaust stream The voltage produced by the O2 sensor is a direct ratio to the oxygen level in the exhaust stream this voltage is used by the computer to change the air fuel mixture Connect jumper wires between the connector and the sensor Connect the test probes in par allel Positive to the signal line negative to the ground circuit The test will check oxygen sensor signal output levels Disconnect the vehicle wiring harness at the sensor Install a Turn the ignition key ON do not jumper wire start the engine Select the Voltage range with the rotary switch Insert Observe the bar graph display Black lead in COM terminal The voltage drop should change as the position of the signal arm on the potentiometer moves sig nal sweep Red lead in V O RPM terminal Connect the test probes in par allel Positive to the jumper Refer to the manufacturer s speci wire negative to the engine fications If the voltage change is ground not within specifications look for i sources of resistance due to poor Vehicle engine must be running Black at operating temperature fast idle at 2 000 RPM for two min utes connectors connections or breaks in the wiring Voltage readings should move bet
27. put devices sensors are Mixture Control solenoids The Temperature sensors amount of ON time is measured Negative 2 wire devices as a percent of the total ON OFF Cyels cycle The meter can read the negative or positive slope and display it as a percent 96 of the total cycle 3 wire devices Oxygen sensor Pressure sensors Primary output devices actuators are a form of an electromagnet that is either ON or OFF The ON OFF signal in general will be in one of three configurations Frequency Hz What is it ON or OFF only switch Duty cycle measured in percent of high or low time or dwell Frequency is the number of times degrees mixture control solenoid a voltage pattern repeats positive 7 compared to negative ON com pared to OFF during one 1 sec 0 Volts ond of time For example fre quency Hz measurements are Volts specified for digitally controlled amp Manifold Absolute Pressure sen sors The frequency of the ON 1 Second OFF signals per second are mea Analog Signal sured and displayed Frequency Hz is shown as Ana log A continuous positive to nega e tive cycle or Digital A positive to 0 Volts negative ON to OFF cycle 1 Second Digital Signal 47 48 Basic Component Testing Basic Component Testing Component Tests Input Component Tests Input Cont d 1 Temperature Tests 2 Thermistor Variable Resistance
28. r Controlled Systems Cont d Basic Daignostics for the Computer Controlled Engine There are two important steps that must always be followed when diagnosing and repairing vehicles with computer controls Do basic engine diagnostics first Many problems can be traced to lack of routine maintenance on components such as plug wires filters and spark plugs Also check for vacuum leaks on any vehicle new or old A complete engine diagnosis should precede any electrical system diagnostics Follow the published Diagnostic Charts EXACTLY through every step to make a repair on a computer component 45 Basic Component Testing Computer Controlled Systems Cont d Self Daignostic Computer Systems One of the functions of the vehicle computer is to record fault codes produced when a sensor or actuator fails These failures are usually displayed as a Current Code or as an History Code Current Codes are further grouped into Hard Failures and Intermittent Failures Be aware however that some vehicle manufacturers use different terminology and older vehicles do not have all of the groups of codes described Current Codes are faults that are active Hard Failure causes the dash Check Engine light to remain ON Intermittent Failure causes the dash Check Engine light to flicker and then go OFF after a short period of time Generally the trouble code stays in the computer memory History Codes are stored co
29. select AC Crank engine 10 15 seconds at normal speed measure voltage Resistance Test Voltage Output Resistance on a good pick up coil will match AC output volt age Ex 950 Q s 950mV output Resistance can be good but voltage low if the magnet has lost magnetism or if the reluctor is too far from the stator Air gap 41 Basic Diagnostic Testing Ignition System Tests Cont d 6 Hall Effect Sensor Voltage Test V This test checks for switching action in any Hall Effect sensor Ignition RPM Crankshaft etc Set the rotary switch to the Voltage V position Insert Black Lead in COM terminal Red Lead in V O RPM terminal Connect the Black test probe to the negative post on the battery Turn the ignition key ON Touch the Red test probe to the three test point shown Ground reading should be the same voltage as the ground Computer or battery Supply line reading should be the same voltage as the input source Computer or battery Signal Line reading should be or the same voltage as the input Black source Computer or battery The reading will toggle high and low as the shutter rotates 42 Basic Component Testing This chapter describes a computer controlled sensor and actuator system typically found on today s automobile Test procedures are also provided for the basic groups of electrical input and output compone
30. st 92 38 3 Secondary Ignition Wire Resistance Test 2 39 4 Distributor Cap Rotor Resistance Test 2 40 5 Pick up Coil Resistance Voltage Test 2 41 6 Hall Effect Sensor Voltage Test 42 Basic Component Testing 43 Computer Controlled Systems 44 Basic Diagnostics for the Computer Controlled Engine 45 Self Diagnostic Computer Systems 46 Component Testing ccccceseceeeecseeeereseeeeeeueenseeeaes 47 Duty Cycle Whatisit 48 Frequency Hz Whatisit 48 Component Tests Input 1 Temperature 49 2 Thermistor Variable Resistance 2 wire 50 3 Potentiometers Variable Resistance 3 wire 53 4 Oxygen Sensor 02 56 5 Pressure Sensor 57 Component Tests Output Output DEVICES v ossis scende eim diese as zoe e aei RR e ERES 58 Specifications General Specifications Electrical Specifications Introduction Introduction Safety N DANGER e Engines produce carbon monoxide whic
31. sured with the meter test probes connected in series as described Getting Started Maintenance Fuse and Battery Replacement WARNING Avoid electrical shock remove test leads before opening case Do not operate the meter or rotate the meter switch when the case is open 1 To replace a battery or fuse loosen the three screws in the case back and lift off the front case Replace the battery with an 9 Volt battery NEDA 1604 IEC 6F 22 2 If no current measurements are possible check for a blown overload protection fuse Important To prevent contamination of the circuits your hands must be clean and the printed circuit board must be held by the edges Replace the fuses with the same type of fuse 10A is a F10A 600V high energy fast acting fuse mA is a F500mA 250V fast acting fuse Make sure the replacement fuse is centered in the fuse holder 3 Re assemble the case then fasten the three screws 20 Getting Started Trouble Shooting 1 Meter will not turn ON Check the battery contacts for a tight fit Check for a minimum battery voltage of 8 0 volts 2 Ampere reading is erratic or there is no reading at all Disassemble the meter back cover and test the fuses for continuity 3 Meter reading is erratic Printed circuit board contaminated from handling with hands Low battery Open circuit in a test lead frayed or broken wire
32. t A reading of less than 12 4V indicates an undercharged bat tery Recharge before testing NO LOAD TEST Meter Battery Reading Charge Note Leave the battery cable unhooked and proceed to the test on the follow ing page 12 2V 509 12 0V 25 25 Basic Diagnostic Testing Battery Testing Cont d 3 Battery Test Parasitic Load This tests for excessive parasitic drain on the battery e Turn the ignition switch and all accessories OFF Important Do not start the vehicle during this test meter damage may result e Set the rotary switch to 10A e Insert the positive lead into the 10A meter terminal Disconnect the battery positive cable e Connect the positive lead to the positive battery termi nal e Connect the negative lead to the disconnected positive battery terminal Parasitic draw should not exceed 100mA If there is excessive draw remove the circuit fuses one at a time until the excessive draw is located Also check the non fused applications such as head lights computer relays and capacitators in the instru ment panel Reconnect the battery cable for the next test 26 Basic Diagnostic Testing Battery Testing Cont d 4 Battery Test Load This tests the battery s capacity to deliver sufficient cranking volt age Set the rotary switch to Volt age Connect the positive l
33. t on pA and mA ranges 3 0 rdg 3dgts on 10A range AC Accuracy 2 5 rdg 4dgts on pA and mA ranges x 3 596 rdg 4dgts 10A range Frequency response 50Hz to 60Hz Voltage burden 0 2V on 320p A 32mA ranges 2V on 3200pA 320mA ranges Input protection 0 5A 250V fast acting ceramic fuse on input 10A 600V fast acting ceramic fuse on 10A input RESISTANCE Autoranging Ranges 3200 3 2KQ 32KQ 320KQ 3 2MQ 30MQ Resolution 100mQ Accuracy 1 5 rdg 3dgts on 3200 to 320KQ ranges 2 5 rdg 3dgts on 3 2MQ range 5 0 rdg 5dgts on 30 MQ range Overload protection 500VDC or RMS AC 61 Specifications Electrical Specifications Cont d FREQUENCY Ranges 320Hz 3200Hz 32KHz Resolution 0 1Hz Accuracy 1 0 rdg 4dgts on all ranges Sensitivity 3 5V RMS min at gt 20 and 8096 duty cycle Effect reading More than 100 digits at pulse width gt 2uSec Overload protection 500VDC or RMS AC DIODE TEST Test current 0 6mA typical Vf 0 6V Resolution 1mV Accuracy 10 rdg 3dgts Open circuit voltage 3 0Vdc typical Overload protection 500VDC or RMS AC AUDIBLE CONTINUITY Audible threshold Less than 200 Resolution 100mQ Test current 0 7mA Overload protection 500VDC or RMS AC 62 7000 1275
34. test checks for alternator output voltage at the battery Set the rotary switch to Volt age Connect the positive lead to the positvie battery termi nal Connect the negative lead to the negative battery termi nal Make sure all vehicle accesso ries are turned OFF Start the engine and hold at 1500 RPM A reading of 13 1 15 5 voltsis an acceptable charging rate If the voltage is low check for Loose cracked or glazed drive belt Loose or faulty wires or connec tors Defective alternator or regula tor See 2 Alternator Voltage Output Loaded 34 Basic Diagnostic Testing Charging System Tests Cont d 2 Alternator Voltage Output Loaded This test checks for alternator output voltage This testis neces sary only if the vehicle failed 1 Battery test Set the rotary switch to the Voltage setting Connect the positive lead to the battery B output post on the back of the alternator Connect the negative lead to the negative battery termi nal Start the engine and hold a 1500 RPM A reading of 13 1 15 5 volts is an acceptable charging rate 35 Basic Diagnostic Testing Charging System Tests Cont d 3 Alternator Amperage A Output Battery This test checks for alternator charging rate efficiency at the battery Connect Current Clamp leads to the meter
35. ttery Test Surface Discharge Note Remove the positive and negative battery cables and thoroughly clean the cable terminals and the battery posts Reassemble and begin testing The ignition switch must be OFF to prevent damaging the vehicle computer when connecting or disconnecting battery cables This test checks for a low current discharge across the battery case e Set the rotary switch to Voltage e Connect the negative lead to the negative battery post Touch the positive lead to the battery case around the posi tive 4 battery post Do not touch the post A reading of more than 0 5V indicates excessive surface dis charge Black Dirt moisture and corrosion are a cause of surface discharge Clean the battery with a baking soda and water solution Do not allow the solution to get into the battery 24 Basic Diagnostic Testing Battery Testing Cont d 2 Static Battery Test No Load This test checks for battery charge state Turn the headlights on for 15 seconds to dissipate battery surface charge IMPORTANT The ignition switch must be OFF when con necting or disconnecting bat tery cables to prevent damag ing the vehicle computer e Disconnect the negative bat tery terminal e Set the rotary switch to Voltage e Connect the positive lead to the positive battery post Connect the negative lead to the negative battery pos
36. urn to autoranging press and hold the RANGE button for 2 seconds Note e f the range is too high the readings are less accurate f the range is too low the meter shows OL over limit Data Hold The Data Hold Feature stores the last reading in memory e Press the Data Hold button once to hold the present reading e Press the Data Hold button again to exit and resume readings Getting Started Meter Functions Voltage V The meter will automatically select the best voltage V range Press the Alternate Function button to select AC or DC Insert e Black lead in COM terminal e Red lead in V Q RPM terminal Touch the Black probe to ground or to the negative circuit Touch the Red probe to the circuit coming from the power source IMPORTANT voltage must be measured in parallel Red probe measuring circuit from power source Accuracy Selection of a lower range will move the decimal point one place and increase the accu racy of the reading An OL Over Limit display means the range is too low select the next higher range Analog Bar Graph The Bar graph is easier to read when the data causes the digi tal display to rapidly change It is also useful for trend setting or directional data SAMA Black Red AWARNING When measuring voltage be sure the Red test lead is in the terminal marked V If the test lead is in an A
37. ween 0 2 lean and O 8 rich The average DC voltage should be around 0 50 55 56 Basic Component Testing Component Tests Input Cont d 5 Pressure sensor Tests The electrical tests for pressure sensors such as the Manifold Absolute Pressure MAP and Barometric Pressure BARO vary greatly depending upon type and manufacturer Consult the vehicle service manual for the schematic specifcations and test procedures General Testing Procedures Note You cannot do a resistance 2 test for pressure sensors Analog Sensor An analog sensor can be tested with the same series of voltage V tests suggested for 3 wire potentiometers In place of sweeping the sensor use a vacuum pump to vary the pressure on the sensor Digital Sensor Set the meter rotary switch to the Hz setting and perform the same series of tests suggested for 3 wire potentiometer voltage tests In place of sweeping the sensor a vacuum pump is generally used to vary the pressure on the sensor In all cases refer to a vehicle service manual for the correct procedure 57 Basic Component Testing Component Tests Output Output Devices The electrical tests for output devices vary greatly depending upon type and manufacturer Consult the vehicle service manual for the schematic specifications and test procedures Primary output devices actuators are a form of an electromagnet that is either ON or OFF The ON OFF signal in gener
38. witch to the Frequency range that gives the most accurate measurement reading Insert Black lead in COM terminal Red lead in V Q RPM terminal Connect the Black test probe to ground Connect the Red test probe to the signal out wire of the sensor to be tested Black Ground Signal Out Side Side Signal Side Select the RPM range with the rotary switch OR Select the X10RPM range with rotary switch 1 000 to 12 000 RPM Multiply the displayed reading times ten to get actual RPM Insert the inductive pick up con necting terminal into the meter e Ground lead in COM terminal Output lead in V Q RPM termi nal Connect the inductive pickup to a spark plug wire If no reading is received unhook the clamp turn it over and connect again Note e Position the inductive pick up as far away from the distributor and the exhaust manifold as possible e Position the inductive pick up to within six inches of the spark plug or move it to another plug wire if no reading or an erratic reading is received Getting Started Meter Functions RPM X10RPM 16 Getting Started Meter Functions Duty Cycle 96 Select the 96 Duty Cycle range with the rotary switch Insert Black lead in COM terminal Red lead in V Q RPM terminal Connect the Black test probe to the ground Connect the Red test probe to the signal wire circuit The illustrat
39. y eene ener 15 RPM x ORPM ssse e nennen nennen 16 Duty Cycle sssssseee emen 17 18 AC or DC Current th raa det 19 Maintenance Fuse and Battery 20 Trouble Shooting eeren Ms SRI 21 Basic Diagnostic Testing eee 22 Electrical System Diagnostics semen 23 Battery Testing 1 Battery Test Surface Discharge 424 2 Static Battery Test No Load 25 3 Battery Test Parasitic Load sen 26 4 Battery Test Load em 27 Voltage Drop Testing eee mH 28 1 Negative Engine Ground 9 2 Negative Chassis 30 3 Battery Power to Starter Solenoid 31 4 Battery Power to Complete Starter Circuit 32 Starter Motor Testing 1l Starter Current sss 33 Introduction Contents Cont d Basic Diagnostic Testing Cont d Charging System Tests 1 Battery vie o NY IRE R PAR SERE RAA 34 2 Alternator Voltage Output Loaded 35 3 Alternator Amperage A Output Battery 36 Ignition System Tests 1 Ignition Coil Primary Resistance Test X2 37 2 Ignition Coil Secondary Resistance Te
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