Actron® AutoAnalyzer™ User Manual
Contents
1. 1 If engine is HOT let it COOL down before proceeding 2 Disconnect ignition coil from g ignition system 3 Insert BLACK test lead into COM test lead jack see Fig 22 9 4 Insert RED test lead into VQ mA gt test lead jack 5 Turn multimeter rotary switch to 2000 range 6 Touch RED and BLACK multi meter leads together and view reading on display 10 Connect test leads Connect RED test lead to pri mary ignition coil positive terminal Connect BLACK test lead to pri mary ignition coil negative terminal Referto vehicle service manual for location of primary ignition coil terminals View reading on display Subtracttestlead resistance found in Step 6 from above reading If vehicle is DIS repeat Steps 7 and 8 for remaining ignition coils Test Results Primary Coil Typical resistance range of pri mary ignition coils is 0 3 2 00 Refer to vehicle service manual foryour vehicles resistance range Fig 22 9 Secondary oil E vn 2000 200 500 Red 200 500 D 200m a An 19 S tv tiv OM 10Amax VOmA COM e 4 A Typical Cylindrical Ignition Coil 11 Turn multi meter rotary switch to 200kQ range amp Black see Fig 23 V 12 Move RED test lead to secondary ig Primary nition coil ter Coil minal Refer to ve hicle service oil Secondary C Typical Cylindrical Ignition2. NOTE Some relays and sole noids have a diode placed across the coil Starting Charging System Testing The starting system turns over the engine It consists of the battery starter motor starter solenoid and or relay and associated wiring and connections The charging system keeps the battery charged when the engine is running This system consists of the alternator voltage regulator battery and associated wiring and connections The digital multimeter is a useful tool for checking the operation of these systems No Load Battery Test Before you do any starting charging system checks you must first test the battery to make sure it is fully charged Test Procedure see Fig 17 1 Turn Ignition Key OFF 2 Turn ON headlights for 10 sec onds to dissipate battery sur face charge 3 Insert BLACK test lead into COM test lead jack 4 Insert RED test lead into VO mA gt t test lead jack 5 Disconnect positive battery cable 6 Connect RED test lead to posi tive terminal of battery 7 Connect BLACK test lead to negative terminal of battery 8 Turn multimeter rotary switch to 20V DC range 9 View reading on display 10 Test Results Compare display reading in Step 9 with the following chart Percent Voltage Battery is Charged 12 60V or greater 100 12 45V 75 12 30V 50 12 15V 25 If battery is not 100 charged then charge it before doing any
3. actron AutoAnalyzer OPERATING INSTRUCTIONS CP7665 SAFETY GUIDELINES TO PREVENT ACCIDENTS THAT COULD RESULT IN SERIOUS INJURY AND OR DAMAGE TO YOUR VEHICLE OR TEST EQUIPMENT CAREFULLY FOLLOW THESE SAFETY RULES AND TEST PROCEDURES Always wear approved eye protection 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 Always make sure the vehicle is in park Automatic transmission or neutral manual transmission and that the parking brake is firmly set Block the drive wheels Never lay tools on vehicle battery You may short the terminals together causing harm to yourself the tools or the battery Never smoke or have open flames near vehicle Vapors from gasoline CAUTION and charging battery are highly flammable and explosive Never leave vehicle unattended while running tests Always keep a fire extinguisher suitable for gasoline electrical chemical fires handy Always use extreme caution when working around the ignition coil distributor cap ignition wires and spark plugs These components contain High Voltage when the engine is running Always turn ignition key OFF when connecting or disconnect ing electrical components unless otherwise instructed Always follow vehicle manufacturer s warnings cautions and service proc
4. tive side of voltage source 4 Connect BLACK test lead to negative side of voltage source NOTE If you don t know which side is positive and which side is negative then arbi trarily connect the RED test lead to one side and the BLACK to the other The multimeter auto matically senses polarity and will display a minus sign when negative polarity is measured If you switch the RED and BLACK test leads positive polarity will now be indicated on the display Measuring negative voltages causes no harm to the multim eter 5 Turn multimeter rotary switch to desired voltage range If the approximate voltage is un known start at the largest voltage range and decrease to the appro priate range as required See Setting the Range on page 6 6 View reading on display Note range setting for correct units NOTE 200mV 0 2V Measuring AC Voltage This multimeter can be used to mea sure AC voltages in the range from 0 to 500V To measure AC Voltages see Fig 8 Fig 8 Black 1 Insert BLACK test lead into COM test lead jack 2 Insert RED test lead into VO mA test lead jack 3 Connect RED test lead to one side of voltage source 4 Connect BLACK test lead to other side of voltage source 5 Turn multimeter rotary switch to desired voltage range If the approximate voltage is un known start at the largest voltage range and decre
5. while wire is flexed Bad Ignition Wire Display read ing erratically changes as igni tion wireis flexed or display read ing is not within manufacturers specification Magnetic Pick Up Coils Reluctance Sensors Reluctance sensors are used when ever the vehicle computer needs to know speed and position of a rotat ing object Reluctance sensors are commonly used in ignition systems to determine camshaft and crank shaft position so the vehicle com puter knows the optimum time to fire the ignition coil s and turn on the fuel injectors This test checks the reluctance sensor for an open or shorted coil This test does not check the air gap or voltage output of the sensor Test Procedure see Fig 25 5 Turn multimeter rotary switch to 2000Q range View reading on display while flexing sensor wires in sev eral places Typical resistance range is 150 10002 Referto vehicle service manual for your vehicles resistance range As you flex sensor wires the display should remain steady 7 Test Results Good Sensor Dis Fig 25 Reluctance Sensor Reluctor en Magnet Ni Blac 1 Insert BLACK test lead into COM test lead jack 2 Insert RED test lead into VO mA gt test lead jack 3 Connect RED test lead to ei ther sensor pin 4 Connect BLACK test lead to remaining sensor pin play reading is within manufacturers speci fication a
6. better fuel economy To do its job a computer controlled engine uses electronic sensors to find out what is happening in the engine 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 The digital multimeter is a useful tool for checking sensor operation Oxygen 0 Type Sensors Titania Type Oxygen Sensor The Oxygen Sensor produces a volt age or resistance based on the amount of oxygen in the exhaust stream A low voltage high resis tance indicates a lean exhaust too much oxygen while a high voltage Zirconia Type low resistance indicates a rich ex Oxygen Sensor haust not enough oxygen The computer uses this voltage to ad just the air fuel ratio The two types of O Sensors commonly in use are Zirconia and Titania Refer to illus 2 tration for appearance differences Exposed flat element Flutes Remove Oxygen Sensor from vehicle of the two sensor types 3 Insert BLACK test lead into Test Procedure see Fig 27 COM test lead jack 1 If engine is HOT let it COOL 4 Insert RED test lead into down before proceeding VQ mA test lead jack IB 1 wire or 3 wire Ground is sensor housing 2 wire or 4 wire Ground is in sensor wiring harness Test heater circuit If sensor contains 3 or more wires then your vehicle uses a heated O sensor Re
7. is possible that the battery battery cables start ing system cables starter solenoid or starter motor are defective Voltage Drops This test measures the voltage drop across wires switches cables solenoids and connections With this test you can find excessive resistance in the starter system This resistance restricts the amount of current that reaches the starter motorresulting in low battery load voltage and a slow cranking engine at starting Test Procedure see Fig 20 5 Turn multimeter rotary switch to 200mV DC range 1 Disableignition system so ve hicle won t start If multimeter overranges turn mul timeter rotary switch to the Disconnect the primary of the ignition coil or the distributor pick Fe lg pee el pes Setting up coil or the cam crank sensor e Range on page 6 to disable the ignition system Crank engine until steady Refer to vehicle service manual reading is on display for disabling procedure Record results at each point 2 Insert BLACK test lead into as displayed on multimeter COM test lead jack Repeat Step 4 amp 5 until all 3 Insert RED test lead into points are checked VO mA gt test lead jack Test Results 4 Connect test leads Estimated Voltage Drop of Refer to Typical Cranking Volt Starter Circuit Components age Loss Circuit Fig 20 Component Voltage Connect RED and BLACK test V leads alternately between 1 amp 2 SMSa 300m 2 amp 3 4 amp 5 5
8. 800 RPM Hold this speed through Step 1 1 Have an assistant help hold speed View reading on display Voltage reading should not change from Step 7 by more than 0 5V Load the electrical system by turning on the lights wind shield wipers and setting the blower fan on high View reading on display Voltage should not drop down below about 13 0V Shut off all accessories re turn engine to curb idle and shut off 13 Test Results If voltage readings in Steps 7 9 and 11 were as expected then charging system is nor mal If any voltage readings in Steps 7 9 and 11 were different then shown here or in vehicle ser vice manual then check for a loose alternator belt defective regulator or alternator poor connections or open alterna tor field current Referto vehicle service manual for further diagnosis Ignition System Testing The ignition system is responsible for providi ng the spark that ignites the fuel in the cylinder Ignition system components that the digital multimeter can test are the primary and secondary ignition coil resistance spark plug wire resistance and reluctance pick up coil sensors Ignition Coil Testing This test measures the resistance 7 of the primary and secondary of an ignition coil This test can be used for distributorless ignition systems DIS provided the primary and sec ondary ignition coil terminals are easily accessible Test Procedure
9. Coil Primary Coil 13 14 15 manual for location of second ary ignition coil terminal Verify BLACK test lead is con nected to primary ignition coil negative terminal View reading on display If vehicle is DIS connect test leads to terminals of the sec ondary ignition coil Repeat for remaining ignition coils Test Results Secondary Coil Typical resistance range of secondary ignition coils is 6 0kQ 30 0kQ Refer to vehicle service manual for your vehicles re sistance range 16 17 Repeat test procedure for a HOT ignition coil NOTE It is a good idea to test ignition coils when they are both hot and cold because the resis tance of the coil could change with temperature This will also help in diagnosing intermittent ignition system problems Test Results Overall Good Ignition Coil Resistance readings in Steps 10 15 and 16 were within manufacturers speci fication Bad Ignition Coil Resistance readings in Steps 10 15 and 16 are not within manufacturers specification Ignition System Wires This test measures the re sistance of spark plug and coil tower wires while they are being flexed This test can be used for distributorless ignition sys tems DIS provided the sys tem does not mount the igni tion coil directly on the spark plug Test Procedure 1 Spark Plug Wire Remove ignition sys tem wires one at a time fro
10. TEST LEAD JACKS COM BLACK Test Lead is always inserted in the COM jack RED Test Lead is in serted in the jack cor responding to the multimeter ro tary switch setting 10 DISPLAY LIGHT Press button to illuminate the dis play DISPLAY Used to display all measurements and multimeter information Low Battery If this symbol ap pears in the lower left corner of the display then replace the internal 9V battery See Fuse and Battery replacement on Always connect TEST LEADS to the F page 7 multimeter before connecting them to the circuit under test High Voltage 10Amax VOmA 7 indicator Overrange Indi DC AMPS DC VOLTS AC VOLTS M cation If 1 or OHMS DIODES 1 appears on the 1 5V 9V and 12V left side of the dis BATTERY TESTS play then the mul timeter is set to a range that is too 7 AG VOLTS Small for the This function is used for measur present measure ing AC Voltages in the range of 0 ment being taken to 500V Increase the range until this disap pears If itdoes not disappear after all the ranges for a particular func tion have beentried thenthe value being measured is too large for the multimeter to measure See Set ting the Range on page 6 8 DC AMPS This function is used for measur ing DC Direct Current Amps in the range of 0 to 10A 9 1 5V 9V AND 12V BATTERY TEST Zero Adjustment This function is usedto test 1 5V The multimeter will automati
11. ad into VO mA test lead jack Disconnect wiring harness from sensor If testing Intake Air Tempera ture Sensor Remove it from vehicle All other temperature sensors can remain on vehicle for test ing Connect RED test lead to ei ther sensor pin Connect BLACK test lead to remaining sensor pin Turn multimeter rotary switch to desired OHM range If the approximate resistance is unknown start at the largest OHM range and decrease to the appro priate range as required See Setting the Range on page 6 View and record reading on display Disconnect multimeter test leads from sensor and recon nect sensor wiring This step does not apply to in take airtemperature sensors For intake air temperature sensors leave multimeter test leads still connected to sensor Heat up sensor Iftesting Intake Air Temperature Sensor To heat up sensor dip sensor tip into boiling water or Heat tip with a lighter if sensor tip is metal or a hair dryer if sensor tip is plastic View and record smallest read ing on display as sensor is heated You may need to decrease the range to get a more accurate reading For all other temperature sen sors Start engine and let idle until upper radiator hose is warm Turn ignition key OFF Disconnect sensor wiring har ness and reconnect multimeter test leads View and record reading on display 12 Test Results Good Sensor Temper
12. amp 6 68 amp 7 7 amp 9 Wire or Cable 200mV 8 amp 9 and 8 amp 10 Ground 100mV Fig 20 Typical Cranking Voltage Loss Circuit Solenoid This is a representative sample of one type of cranking circuit Your vehicle may use a different circuit with different components or locations Consult your vehicle service manual Component Voltage Battery Cable Connectors 50mV Connections 0 0V Compare voltage readings in Step 6 with above chart If any voltages read high inspect component and connection for defects If defects are found service as necessary Charging System Voltage Test This test checks the charging sys tem to see if it charges the battery and provides powerto the restof the vehicles electrical systems lights fan radio etc Test Procedure see Fig 21 Insert BLACK test lead into COM test lead jack Insert RED test lead into VQ m A gt t test lead jack Turn multimeter rotary switch to 20V DC range Connect RED test lead to posi tive terminal of battery Connect BLACK test lead to negative terminal of battery Start engine Let idle 7 10 11 Turn off all accessories and view reading on display Charging system is normal if display reads 13 2to 15 2 volts f display voltage is not be tween 13 2 to 15 2 volts then proceed to Step 13 Open throttle and Hold engine speed RPM between 1800 and 2
13. ant to measure resistance When making resistance mea surements polarity is not im portant The test leads just have to be connected across the com ponent 6 Turn multimeter rotary switch to desired OHM range If the approximate resistance is unknown start at the largest OHM range and decrease to the ap propriate range as required 7 Viewreading on display Note range setting for correct units NOTE 2KQ 2 0000 2MQ 2 000 0002 If you want to make precise re sistance measurements then subtract the test lead resistance found in Step 4 above from the display reading in Step 7 It is a good idea to do this for resis tance measurements less than 10Q Measuring DC Current This multimeter can be used to mea sure DC currentin the range from 0 to 10A Unlike voltage and resistance measurements where the multimeter is connected across the component you are testing current measure ments must be made with the multim eter in series with the component Isolating current drains and short cir cuits are some DC Current applica tions Fig 10 Electrical Device DC Voltage Source Red Electrical Device To measure DC Current see Figs 10 amp 11 1 Insert BLACK test lead into COM test lead jack 2 Insert RED test lead into 10A test lead jack or mA test lead jack 3 Disconnect or electrically open circuit where you want to measure current Thi
14. ase to the appro priate range as required See Setting the Range on page 6 6 View reading on display NOTE 200mV 0 2V Measuring Resistance Resistance is measured in electrical units called ohms Q The digital multimeter can measure resistance from 0 12 to 20MQ or 20 000 000 ohms Infinite resistance is shown with a 1 on the left side of display See Setting the Range on page 6 Youcan use this multimeter to do any resistance measurement called out in the vehicle service manual Test ing ignition coils spark plug wires and some engine sensors are com mon uses for the OHMS Q function To measure Resistance see Fig 9 1 Turn circuit power OFF To get an accurate resistance measurement and avoid possible damage to the digital multimeter and electrical circuit under test turn off all electrical power in the circuit where the resistance mea surement is being taken Fig 9 Unknown Resistance 2 Insert BLACK test lead into COM test lead jack 3 Insert RED test lead into VO mA gt test lead jack 4 Turn multimeter rotary switch to 200Q range Touch RED and BLACK multim eter leads together and view reading on display Display should read typically 0 22 to 1 52 If display reading was greater than 1 52 check both ends of test leads for bad connections If bad connections are found replace test leads 5 Connect RED and BLACK test leads across component where you w
15. ature sensors HOT re sistance is at least 3000 less than its COLD resistance The key point is that the COLD resistance decreases with in creasing temperature Bad Sensor There is no change between the temperature sensors HOT resistance from the COLD re sistance The temperature sensor is an open or a short circuit Position Type Sensors Position sensors are potentiometers or a type of variable resistor They are used by the computer to deter mine position and direction of move ment of a mechanical device Typi cal position sensor applications are throttle position sensors EGR valve position sensors and vane air flow sensors Test Procedure see Fig 29 1 Insert BLACK test lead into COM test lead jack Insert RED test lead into VO m A gt t test lead jack Disconnect wiring harness from sensor Connect Test Leads Connect RED test lead to sen sor POWER pin Connect BLACK test lead to sensor GROUND pin Referto vehicle service manual for location of sensor POWER and GROUND pins Turn multimeter rotary switch to 20KQ range Typical Toyota Throttle Position Sensor ep red MAN ves h c 4 GROUND SIGNAL IDLE SWITCH View and record reading on Depending on hook up the dis display play reading will either increase Display should read some re or decrease in resistance sistance value The display reading should ei If m
16. cally zero 9V and 12V batteries under on the Volts Amps and Battery Test load functions Automatic Polarity Sensing The multimeter display will show a minus sign on the DC Volts and DC Amps functions when test lead hook up is re versed Setting the Range Two of the most commonly asked questions about digital multimeters are What does Range mean and How do I know what Range the mul timeter should be set to What Does Range mean Range refers to the largest value the multimeter can measure with the rotary switch in that position If the multimeter is set to the 20V DC range then the highest voltage the multimeter can measure is 20V in that range EXAMPLE Measuring Vehicle Bat tery Voltage See Fig 1 the display If you are in the highest range and the multimeter is stil showing that it is overranging then the value being measured is too large for the multimeter to measure How do I know what Range the multimeter should be set to Let s assume the multimeter is con nected to the battery and set to the 20V range The display reads 12 56 This means there is 12 56V across the battery terminals Now assume we Set the multimeter to the 2000mV range See Fig 2 The multimeter display now shows a 1 and nothing else This means the multimeter is being overranged or in other words the value being measured is larger than the current range The ran
17. e current draw is lo cated Non Fused circuits such as headlights relays and sole noids should also be checked as possible current drains on battery When source of excessive cur rent drain is found service as necessary Cranking Voltage Battery Load Test This test checks the battery to see if it is delivering enough voltage to the starter motor under cranking conditions Test Procedure see Fig 19 1 Disable ignition system so ve hicle won t start Disconnect the primary of the ignition coil or the distributor pick up coil or the cam crank sensor to disable the ignition system Refer to vehicle service manual for disabling procedure 2 Insert BLACK test lead into COM test lead jack 3 Insert RED test lead into VO m A gt t test lead jack 4 Connect RED test lead to posi tive terminal of battery 5 Connect BLACK test lead to negative terminal of battery 6 Turn multimeter rotary switch to 20V DC range 7 Crank engine for 15 seconds continuously while observing display 8 Test Results Compare display reading in Step 7 with chart below Voltage Temperature 9 6V or greater 70 F and Above 9 5V 60 F 9 4V 50 F 9 3V 40 F 9 1V 30 F 8 9V 20 F 8 7V 10 F 8 5V 0 F If voltage on display corresponds to above voltage vs temperature chart then cranking system is normal If voltage on display does not corre spond to chart then it
18. edures Some vehicles 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 unexpect edly 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 Section 1 Multimeter Basic Functions Digital multimeters or DMMs have many special features and functions This section defines these features and functions and explains how to use these functions to make various measurements fi FA D actron f Li LILLI AutoAnalyzer se 15 A 10 5 gt 200mA MAX 1 UNFUSED 10Amax VOmA gt COM 9v Functions and Display Definitions 1 ROTARY SWITCH Switch is rotated to turn multimeter ON OFF and select a function DC VOLTS This function is used for measur ing DC Direct Current Voltages in the range of 0 to 500V OHMS This function is used for measur ing the resistance of a component in an electrical circuit in the range of 0 10 to 20MQ Q is the electri cal symbol for Ohms DIODE CHECK This function is used to check whether a diode is good or bad HOLD Press HOLD button to retain data on display In the hold mode the H annunciator is displayed
19. f the decimal point This changes the accuracy of the measurement by either increas ing or decreasing the number of digits after the decimal point Battery and Fuse Replacement Important A 9 Volt battery must be installed before using the digital mul timeter see procedure below for installation Battery Replacement 1 Turn multimeter rotary switch to OFF position 2 Remove test leads from multimeter 3 Remove screws from back of multimeter 4 Remove back cover 5 Install a new 9 Volt battery 6 Re assemble multimeter Fuse Replacement 1 Turn multimeter rotary switch to OFF position 2 Remove test leads from multimeter 3 Remove screws from back of multimeter 4 Remove back cover 5 Remove fuse 6 Replace fuse with same size and type as originally installed 5mm x 20mm 200mA 250V fast acting 7 Re assemble multimeter Measuring DC Voltage This multimeter can be used to mea sure DC voltages in the range from 0 to 500V You can use this multimeter to do any DC voltage measurement called out in the vehicle service manual The most common applica tions are measuring voltage drops and checking if the correct voltage arrived at or is being produced by a sensor or a particular circuit To measure DC Voltages see Fig 7 1 Insert BLACK test lead into COM test lead jack 2 Insert RED test lead into VO mA test lead jack 3 Connect RED test lead to posi
20. ferto vehicle service manual for location of heater pins Connect RED test lead to ei ther heater pin Connect BLACK test lead to remaining heater pin Turn multimeter rotary switch to 2000 range View reading on display Compare reading to manufacturer s specification in vehicle service manual Remove both test leads from sensor Connect BLACK test lead to sensor GROUND pin f sensoris 1 wire or 3 wire then GROUND is sensor housing f sensor is 2 wire or 4 wire then GROUND is in sensor wir ing harness Referto vehicle service manual for Oxygen Sensor wiring dia gram Connect RED test lead to sen sor SIGNAL pin Test Oxygen Sensor Turn multimeter rotary switch to 2000mV range for Zirconia Type Sensors 200KQ range for Titania Type Sensors Light propane torch Firmly grasp sensor with a pair of locking pliers 10 1 Thoroughly heat sensor tip as hot as possible but not glow ing Sensor tip must be at 660 F to operate Completely surround sensor tip with flame to deplete sensor of oxygen Rich Condition Multimeter display should read 600mV or greater for Zirco nia Type Sensors an Ohmic Resistance value for Titania Type Sensors Reading will vary with flame temperature While still applying heat to sen sor move flame such that oxy gen can reach sensor tip Lean Condition Multimeter display sh
21. ge should be in creased until a value is shown on The multimeter should be set in the lowest possible range without overranging EXAMPLE Measuring an unknown resistance Let s assume the multimeter is con nected to an engine coolant sensor with unknown resistance See Fig 3 Start by setting the multimeter to the largest OHM range The display reads 0 0Q or a short circuit HU AutoAnalyzer This sensor can t be shorted so re duce the range setting until you get a value of resistance At the 200KQ range the multimeter measured a value of 4 0 This means there is 4KQ of resistance across the engine coolant sensor termi nals See Fig 4 If we change the multimeter to the 20KQ range See Fig 5 the dis play shows a value of 3 87KQ The actual value of resistance is 3 87KQ and not 4KQ that was measured in the 200KQ range This is very im portant because if the manufacturer specifications say that the sensor should read 3 8 3 9KQ at 70 F then on the 200KQ range the sensor would be defective but at the 20KQ range it would test good Now set the multimeter to the 20009 range See Fig 6 The display will indicate an overrange condition be cause 3 87KQ is larger than 2KQ This example shows that by de creasing the range you increase the accuracy of your measurement When you change the range you change the location o
22. iring harness 6 Turn multimeter rotary switch to desired OHM range If the approximate resis tance is unknown start at 1 Insert BLACK test lead into COM test lead jack 2 Insert RED test lead into VO mA gt test lead jack 3 Turn multimeter rotary switch to 2000 range Touch RED and BLACK multim eter leads together and view reading on display Display should read typically 0 2 1 52 the largest OHM range and decrease to the appropri ate range as required View reading on display Note range setting for correct units If display reading is 102 or less subtract test lead resis tance found in Step 3 from above reading Compare reading to manufac turers specifications for fuel in jector coil resistance This information is found in vehicle service manual Test Results Good Fuel Injector resistance Resistance of fuel injector coil is within manufacturers specifica tions Bad Fuel Injector resistance Re sistance of fuel injector coil is not within manufacturers speci fications NOTE If resistance of fuel in jector coil is within manufactur ers specifications the fuel injec tor could still be defective It is possible that the fuel injector is clogged or dirty and that is caus ing your driveability problem Testing Engine Sensors In the early 1980 s computer controls were installed in vehicles to meet Federal Government regulations for lower emissions and
23. isplay reading should ei To test these switches follow ther start at or end at the ap the Testing Switches test pro proximate resistance value mea cedure on page 13 sured in Step 6 When you are told to operate 9 Test Results Switch then move throttle link Good Sensor Display read age ing gradually increases or de Vane Air Flow Sensor creases in resistance as sensor is opened and closed Slowly open vane door from closed to open by pushing on it Bad Sensor There is no change with a pencil or similar object in resistance as sensor is opened This will not harm sensor or closed Electrical Specifications DC Volts Range 200mV 2000mV 20V 200V Accuracy 0 5 rdg 2 dgts Range 500V Accuracy 0 8 rdg 2 dgts AC Volts Range 200V 500V Accuracy 1 2 rdg 10 dgts DC Current Range 200uA Accuracy 1 0 rdg 2 dgts Range 200mA Accuracy 1 2 rdg 2 dgts Range 10A Accuracy 2 0 rdg 5 dgts Resistance Range 2002 Accuracy 0 8 rdg 5 dgts Range 20002 20KQ 200KQ Accuracy 0 8 rdg 2 dgts Range 20MQ Accuracy 1 0 rdg 5 dgts Battery Test Range 1 5V 9V 12V Accuracy 10 rdg 2 dgts Diode Test Resolution 1mV ACTRON HAND TOOLS
24. losed If the reading is overrange The switch is open 7 Repeat Step 6 to verify switch operation Testing Solenoids and Relays This test checks to see if a solenoid or relay has a broken coil If the coil tests good itis still possible that the relay or solenoid is defective The relay can have contacts that are welded or worn down and the sole noid may stick when the coil is ener gized This test does not check for those potential problems To test Solenoids and Relays see Fig 16 Fig 16 Relay or Solenoid QU 1 Insert BLACK test lead into COM test lead jack 2 Insert RED test lead into VO mA gt t test lead jack 3 Turn multimeter rotary switch to 2002 function Most solenoids and relay coil resistances are less than 2000 4 Connect BLACK test lead to one side of coil 5 Connect RED test lead to other side of coil 6 View reading on display Typical solenoid relay coil re sistances are 200Q or less e Refer to vehicle service manual for the device s resistance range If meter overranges turn multi meter rotary switch to next higher range see Setting the Range on page 6 7 Test Results Good Solenoid Relay Coil Dis play in Step 6 is within manufac turers specification Bad Solenoid Relay Coil Display in Step 6 is not within manufacturers specifications Display reads overrange on every ohms range indicating an open circuit
25. m engine Always grasp ignition system wires on the boot when removing Twist the boots about a half turn while pulling gently to re move them Referto vehicle service manual for ignition wire removal pro cedure e Inspect ignition wires for cracks chaffed insulation and corroded ends NOTE Some Chrysler products use a positive locking terminal electrode spark plug wire These wires can only be removed from inside the distributor cap Dam age may result if other means of removal are attempted Refer to vehicle service manual for pro cedure NOTE Some spark plug wires have sheet metal jackets with the following symbol lt This type of plug wire contains an air gap resistor and can only be checked with an oscilloscope Insert BLACK test lead into COM test lead jack see Fig 24 Insert RED test lead into VO mA test lead jack Connect RED test lead to one end of ignition wire and BLACK test lead to other end Turn multimeter rotary switch to 200KQ range View reading on display while flexing ignition wire and boot in several places Typical resistance range is 3KQ to 50KQ or approximately 10KQ per foot of wire Referto vehicle service manual for your vehicles resistance range As you flex ignition wire the display should remain steady Test Results Good Ignition Wire Display reading is within manufacturers specification and remains steady
26. more start ing charging system tests Engine Off Battery Current Draw This test measures the amount of current being drawn from the battery when the ignition key and engine are both off This test helps to identify possible sources of excessive bat tery current drain which could even tually lead to a dead battery 1 Turn Ignition Key and all ac cessories OFF Make sure trunk hood and dome lights are all OFF See Fig 18 2 Insert BLACK test lead into COM test lead jack 3 Insert RED testlead into 10A or mA test lead jack 4 Disconnect positive battery cable 5 Connect RED test lead to posi tive battery terminal 6 Connect BLACK test lead to positive battery cable NOTE Do not start vehicle dur ing this test because multimeter damage may result 7 Turn multimeter rotary switch to 10A DC or 200 mA posi tion 8 View reading on display Typical current draw is 100mA 1mA 0 0014 Referto vehicle service manual for manufacturers specific En gine Off Battery Current Draw NOTE Radio station presets and clocks are accounted for in the 100mA typical current draw Test Results Normal Current Draw Display reading in Step 8 is within manu facturers specifications Excessive Current Draw Display reading in Step 8 is well outside manufacturers specifications Remove Fuses from fuse box one at a time until source of excessiv
27. nd remains steady while sensor wires are flexed Bad Sensor Display reading erratically changes as sensor wires are flexed or display reading is not within manufacturers specification Fuel System Testing The requirements for lower vehicle emissions has increased the need for more precise engine fuel control Auto manufacturers began using elec tronically controlled carburetors in 1980 to meet emission requirements Today s modern vehicles use electronic fuel injection to precisely control fuel and further lower emissions The digital multimeter can be used to measure fuel injector resistance Measuring Fuel Injector Resistance Fuel injectors are similar to sole noids They contain a coil that is switched ON and OFF by the ve hicle computer This test measures the resistance of this coil to make sure itis not an open circuit Shorted coils can also be detected if the specific manufacturer resistance of the fuel injector is known Test Procedure see Fig 26 If display reading was greater than 1 5Q check both ends of test leads for bad connections If bad connections are found re place test leads Disconnect wiring harness from fuel injector Refer to vehicle service manual for pro cedure 5 Connect RED and BLACK test leads across fuel in Typical Fuel Injector a F JOAwx VMA COM o jector pins Make sure you connecttest leads across fuel injector and notthe w
28. o 0 00 5 Disconnect one end of diode from circuit Diode must be totally isolated from circuit in order to test its functionality 6 Connect RED and BLACK test leads across diode and view display Display will show one of three things A typical voltage drop of around 0 7V A voltage drop of 0 volts A 1 will appear indicating the multimeter is overranged Switch RED and BLACK test leads and repeat Step 6 Test Results If the display showed A voltage drop of 0 volts in both directions then the diode is shorted and needs to be replaced A 1 appears in both direc tions then the diode is an open circuit and needs to be re placed The diode is good if the dis play reads around 0 5V 0 7V in one direction and a 1 ap pears in the other direction indicating the multimeter is overranged Testing 1 5V 9V and 12V Batteries Test Procedure see Fig 13 1 Insert BLACK test lead into COM test lead jack 2 Insert RED test lead into VQ m A gt t test lead jack 3 Turn multimeter rotary switch to 1 5V 9V or 12V range 4 Connect RED test lead to posi tive terminal of battery 5 Connect BLACK test lead to negative terminal of battery 6 View reading on display Section 2 Automotive Testing The digital multimeter is a very use ful tool for trouble shooting automo tive electrical systems This section describes how to use
29. ould read 400mV or less for Zirconia Type Sensors an overrange condition for Titania Type Sensors See Setting the Range on page 6 Repeat Step 8 a few times to verify results Extinguish Flame let sensor cool and remove test leads Test Results Good Sensor Heater Circuit resistance is within manufacturer s specifi cation Oxygen Sensor output signal changed when exposed to a rich and lean condition Bad Sensor Heater Circuit resistance is not within manufacturer s specifi cation Oxygen Sensor output signal did not change when exposed to a rich and lean condition Oxygen sensor output voltage takes longer than 3 seconds to switch from a rich to a lean condition Temperature Type Sensors Atemperature sensoris athermistor or a resistor whose resistance changes with temperature The hot ter the sensor gets the lower the resistance becomes Typical ther mistor applications are engine cool ant sensors intake air temperature sensors transmission fluid tempera ture sensors and oil temperature sensors Test Procedure see Fig 28 Fig 28 Hair A Typical Intake Air Temperature Sensor 1 If engine is HOT let it COOL down before proceeding Make sure all engine and trans mission fluids are at outside air temperature before proceeding with this test 2 Insert BLACK test lead into COM test lead jack 10 11 Insert RED test le
30. s is done by Disconnecting wiring harness Disconnecting wire from screw on type terminal Unsolder lead from component if working on printed circuit boards Cut wire if there is no other possible way to open electri cal circuit 4 Connect RED test lead to one side of disconnected circuit 5 Connect BLACK test lead to remaining side of discon nected circuit 6 Turn multimeter rotary switch to 10A DC position 200mA or 200A position 7 View reading on display If minus sign appears on dis play then reverse RED and BLACK test leads Testing Diodes A diode is an electrical component that allows current to only flow in one direction When a positive voltage generally greater than 0 7V is ap plied to the anode of a diode the diode will turn on and allow current to flow If this same voltage is applied to the cathode the diode would remain off and no current would flow There fore in order to test a diode you must check it in both directions i e anode to cathode and cathode to anode Diodes are typically found in alterna tors on automobiles Performing Diode Test see Fig 12 Fig 12 Anode _ Cathode 1 Insert BLACK test lead into COM test lead jack 2 Insert RED test lead into VO mA gt test lead jack 3 Turn multimeter rotary switch to function 4 Touch RED and BLACK test leads together to test continu ity Check display should reset t
31. the digital mul timeter to test the starting and charg ing system ignition system fuel system and engine sensors The digital multimeter can also be used for general testing of fuses switches solenoids and relays General Testing The digital multimeter can be used to test fuses switches solenoids and relays Testing Fuses This test checks to see if a fuse is blown To test Fuses see Fig 14 1 Insert BLACK test lead into COM test lead jack 2 Insert RED test lead into VO mA gt test lead jack 3 Turn multimeter rotary switch to 20009 function 4 Connect RED and BLACK test leads to opposite ends of fuse If the reading is zero Fuse is good If the reading is overrange Fuse is blown and needs to be replaced NOTE Always replace blown fuses with same type and rating Testing Switches This test checks to see if a switch Opens and Closes properly To test Switches see Fig 15 Typical Push Button Switch Fig 15 1 Insert BLACK test lead into COM test lead jack 2 Insert RED test lead into VO mA test lead jack 3 Turn multimeter rotary switch to 20000 function 4 Connect BLACK test lead to one side of switch 5 Connect RED test lead to other side of switch If the reading is zero The switch is closed If the reading is overrange The switch is open 6 Operate switch If the reading is zero The switch is c
32. ultimeter is overranging ad ther start at or end at the ap just the range accordingly See proximate resistance value mea Setting the Range on page 6 sured in Step 6 If multimeter overranges on larg Some vane air flow sensors est range then sensor is an have an idle switch and an in open circuit and is defective take air temperature sensor in addition to a potentiometer Move RED test lead to sensor To test idle switch see Testing SIGNAL pin Switches on page 13 Refer to vehicle service manual forlocation of sensor SIGNAL pin When you are told to operate Switch then open vane door Operate Sensor i To test intake air temperature Throttle Position Sensor sensor see Temperature Type Slowly move throttle linkage Sensors on page 29 from closed to wide open posi EGR Valve Position tion Remove vacuum hose from Depending on hook up the dis EGR valve play reading will either in crease or decrease in resis Connect hand vacuum pump tance to EGR valve The display reading should ei Gradually apply vacuum to ther start at or end at the ap slowly open valve Typically proximate resistance value 5to 10 in of vacuum fully opens measured in Step 6 valve Some throttle position sensors Depending on hook up the dis have an Idle or Wide Open play reading will either increase Throttle WOT switch in addi or decrease in resistance tion to a potentiometer e The d
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