operating instructions - actron · 2020-07-15 · terminals. now assume we set the multimeter to...

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IndexSafety Precautions .................................. 2

Vehicle Service Information .................... 3

Visual Inspection ..................................... 3

Electrical Specifications ........................ 32

Warranty ................................................ 96

1. Multimeter Basic Functions

Functions and Display Definitions ...... 4

Setting the Range ............................... 6

Battery and Fuse Replacement .......... 7

Measuring DC Voltage ........................ 8

Measuring AC Voltage ........................ 8

Measuring Resistance ........................ 9

Measuring DC Current ...................... 10

Testing Diodes .................................. 11

Testing Batteries ............................... 12

2. Automotive Testing with the CP7665

General Testing ................................. 13- Testing Fuses ................................. 13- Testing Switches ............................. 13- Testing Solenoids and Relays ........ 14

CP7665

OPERATINGINSTRUCTIONS

Starting / Charging System Testing . 15

- No Load Battery Test ...................... 15

- Engine Off Battery Current Draw ... 16

- Cranking Voltage/Battery Load Test . 17

- Voltage Drops ................................. 18

- Charging System Voltage Test ...... 19

Ignition System Testing .................... 21

- Ignition Coil Testing ........................ 21

- Ignition System Wires ..................... 23

- Magnetic Pick-Up Coils .................. 24

- Reluctance Sensors ........................ 24

Fuel System Testing ......................... 25

- Measuring Fuel Injector Resistance .. 25

Testing Engine Sensors .................... 27

- Oxygen (O2) Type Sensors............. 27

- Temperature Type Sensors ............ 29

- Position Type Sensors –Throttle and EGR Valve Position,Vane Air Flow .................................. 30

Instrucciones en español .... 33Instructions en français ....... 65

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SAFETY GUIDELINESTO PREVENT ACCIDENTS THAT COULD RESULT IN SERIOUS

INJURY AND/OR DAMAGE TO YOUR VEHICLE OR TESTEQUIPMENT, CAREFULLY FOLLOW THESE SAFETY RULES AND

TEST PROCEDURES

• Always wear approved eyeprotection.

• Always operate the vehicle in awell ventilated area. Do not inhaleexhaust gases – they are verypoisonous!

• Always keep yourself, tools andtest equipment away from allmoving or hot engine parts.

• Always make sure the vehicle is inpark (Automatic transmission) orneutral (manual transmission) andthat the parking brake is firmlyset. Block the drive wheels.

• Never lay tools on vehicle battery.You may short the terminalstogether causing harm to yourself,the tools or the battery.

• Never smoke or have open flamesnear vehicle. Vapors from gasoline

All information, illustrations and specifications contained in this manual are based on the latestinformation available from industry sources at the time of publication. No warranty (expressed orimplied) can be made for its accuracy or completeness, nor is any responsibility assumed by ActronManufacturing Co. or anyone connected with it for loss or damages suffered through reliance onany information contained in this manual or misuse of accompanying product. Actron Manufactur-ing Co. reserves the right to make changes at any time to this manual or accompanying productwithout obligation to notify any person or organization of such changes.

and charging battery are highlyflammable and explosive.

• Never leave vehicle unattendedwhile running tests.

• Always keep a fire extinguishersuitable for gasoline/electrical/chemical fires handy.

• Always use extreme caution whenworking around the ignition coil,distributor cap, ignition wires, andspark plugs. These componentscontain High Voltage when theengine is running.

• Always turn ignition key OFFwhen connecting or disconnect-ing electrical components, unlessotherwise instructed.

• Always follow vehiclemanufacturer’s warnings,cautions and service procedures.

CAUTION:Some vehicles are equipped with safety air bags. You must follow vehicleservice manual cautions when working around the air bag components orwiring. 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 upseveral minutes after the ignition key is off (or even if the vehicle battery isdisconnected) because of a special energy reserve module.

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Vehicle Service Manual – Sources For ServiceInformationThe following is a list of sources to obtain vehicle service information for yourspecific vehicle.

• Contact your local Automotive Dealership Parts Department.

• Contact local retail auto parts stores for aftermarket vehicle serviceinformation.

• Contact your local library. Libraries often allow you to check-out automo-tive service manuals.

Do a Thorough Visual InspectionDo a thorough visual and “hands-on” underhood inspection beforestarting any diagnostic procedure! You can find the cause of manyproblems by just looking, thereby saving yourself a lot of time.

• Has the vehicle been servicedrecently? Sometimes things getreconnected in the wrong place,or not at all.

• Don’t take shortcuts. Inspecthoses and wiring which may bedifficult to see due to location.

• Inspect the air cleaner andductwork for defects.

• Check sensors and actuators fordamage.

• Inspect ignition wires for:

- Damaged terminals.

- Split or cracked spark plugboots

- Splits, cuts or breaks in theignition wires and insulation.

• Inspect all vacuum hoses for:

- Correct routing. Refer to ve-hicle service manual, or Ve-

hicle Emission ControlInformation(VECI) decal lo-cated in the engine compart-ment.

- Pinches and kinks.

- Splits, cuts or breaks.

• Inspect wiring for:

- Contact with sharp edges.

- Contact with hot surfaces, suchas exhaust manifolds.

- Pinched, burned or chafed in-sulation.

- Proper routing and connec-tions.

• Check electrical connectors for:

- Corrosion on pins.

- Bent or damaged pins.

- Contacts not properly seatedin housing.

- Bad wire crimps to terminals.

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Section 1. Multimeter Basic FunctionsDigital multimeters or DMMs have many special features and functions. Thissection defines these features and functions, and explains how to use thesefunctions to make various measurements.

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8

4

1

9

7

2

11

6

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Functions and Display Definitions1. ROTARY SWITCH

Switch is rotated to turn multimeterON/OFF and select a function.

2. DC VOLTSThis function is used for measur-ing DC (Direct Current) Voltages inthe range of 0 to 500V.

3. OHMSThis function is used for measur-

ing the resistance of a componentin an electrical circuit in the rangeof 0.1Ω to 20MΩ. (Ω is the electri-cal symbol for Ohms)

4. DIODE CHECKThis function is used to checkwhether a diode is good or bad.

5. HOLDPress HOLD button to retain data

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on display. In the hold mode, the"H" annunciator is displayed.

6. TEST LEAD JACKSBLACK Test Lead isalways inserted in theCOM jack.

RED Test Lead is in-serted in the jack cor-responding to the multimeter ro-tary switch setting.

Always connect TEST LEADS to themultimeter before connecting themto the circuit under test!!

10. DISPLAY LIGHTPress button to illuminate the dis-play.

11. DISPLAYUsed to display all measurementsand multimeter information.

Low Battery – If this symbol ap-pears in the lower left corner of thedisplay, then replace the internal9V battery. (See Fuse and Battery

replacement onpage 7.)

High Voltageindicator

Overrange Indi-cation – If “1” or “-1” appears on theleft side of the dis-play, then the mul-timeter is set to arange that is toosmal l for thepresent measure-ment being taken.

Increase the range until this disap-pears. If it does not disappear afterall the ranges for a particular func-tion have been tried, then the valuebeing measured is too large for themultimeter to measure. (See Set-ting the Range on page 6.)

Zero AdjustmentThe multimeter will automatically zeroon the Volts, Amps and Battery Testfunctions.

Automatic Polarity SensingThe multimeter display will show a minus(-) sign on the DC Volts and DC Ampsfunctions when test lead hook-up is re-versed.

7. AC VOLTSThis function is used for measur-ing AC Voltages in the range of 0to 500V.

8. DC AMPSThis function is used for measur-ing DC (Direct Current) Amps inthe range of 0 to 10A.

9. 1.5V, 9V, AND 12V BATTERYTEST

This function is used to test 1.5V,9V, and 12V batteries underload.

DC VOLTS AC VOLTSOHMS DIODES

1.5V, 9V and 12VBATTERY TESTS

DC AMPS

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Setting the RangeTwo of the most commonly askedquestions about digital multimetersare What does Range mean? andHow do I know what Range the mul-timeter should be set to?

What Does Range mean?

Range refers to the largest valuethe multimeter can measure withthe rotary switch in that position. Ifthe multimeter is set to the 20V DCrange, then the highest voltage themultimeter can measure is 20V inthat range.

EXAMPLE: Measuring Vehicle Bat-tery Voltage (See Fig. 1)

the display. If you are in the highestrange and the multimeter is stillshowing that it is overranging, thenthe value being measured is toolarge for the multimeter to measure.

How do I know what Range themultimeter should be set to?

The multimeter should be set in thelowest possible range withoutoverranging.

EXAMPLE: Measuring an unknownresistance

Let’s assume the multimeter is con-nected to an engine coolant sensorwith unknown resistance. (See Fig. 3)

Start by setting the multimeter to thelargest OHM range. The displayreads 0.0Ω or a short circuit.

Fig. 2

Fig. 1

Let’s assume the multimeter is con-nected to the battery and set to the20V range.

The display reads 12.56. This meansthere is 12.56V across the batteryterminals.

Now assume we set the multimeterto the 2000mV range. (See Fig. 2)

The multimeter display now showsa “1” and nothing else. This meansthe multimeter is being overrangedor in other words the value beingmeasured is larger than the currentrange. The range should be in-creased until a value is shown on

Fig. 3

Red Black

RedBlack

BlackRed

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Fig. 5

This sensor can’t be shorted so re-duce the range setting until you geta value of resistance.

At the 200KΩ range the multimetermeasured a value of 4.0. This meansthere is 4KΩ of resistance acrossthe engine coolant sensor termi-nals. (See Fig. 4)

If we change the multimeter to the20KΩ range (See Fig. 5) the dis-play shows a value of 3.87KΩ. Theactual value of resistance is 3.87KΩand not 4KΩ that was measured inthe 200KΩ range. This is very im-portant because if the manufacturerspecifications say that the sensorshould read 3.8-3.9KΩ at 70°F thenon the 200KΩ range the sensorwould be defective, but at the 20KΩrange it would test good.

Now set the multimeter to the 2000Ωrange. (See Fig. 6) The display willindicate an overrange condition be-cause 3.87KΩ is larger than 2KΩ.

This example shows that by de-creasing the range you increase theaccuracy of your measurement.When you change the range, youchange the location of the decimalpoint. This changes the accuracy ofthe measurement by either increas-

Fig. 6

ing or decreasing the number ofdigits after the decimal point.

Battery and FuseReplacementImportant: A 9 Volt battery must beinstalled before using the digital mul-timeter. (see procedure below forinstallation)

Battery Replacement

1. Turn multimeter rotaryswitch to OFF position.

2. Remove test leads frommultimeter.

3. Remove screws from back ofmultimeter.

4. Remove back cover.

5. Install a new 9 Volt battery.

6. Re-assemble multimeter.

Fuse Replacement

1. Turn multimeter rotaryswitch to OFF position.

2. Remove test leads frommultimeter.

Fig. 4

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3. Remove screws from back ofmultimeter.

4. Remove back cover.

5. Remove fuse.

6. Replace fuse with same sizeand type as originallyinstalled!5mm x 20mm, 200mA, 250V,fast acting.

7. Re-assemble multimeter.

Measuring DC VoltageThis multimeter can be used to mea-sure DC voltages in the range from 0to 500V. You can use this multimeterto do any DC voltage measurementcalled out in the vehicle servicemanual. The most common applica-tions are measuring voltage drops,and checking if the correct voltagearrived at or is being produced by asensor or a particular circuit.

To measure DC Voltages (see Fig. 7):

1. Insert BLACK test lead intoCOM test lead jack.

2. Insert RED test lead into test lead jack.

3. Connect RED test lead to posi-tive (+) side of voltage source.

4. Connect BLACK test lead to

Fig. 7

negative (-) side of voltagesource.

NOTE: If you don’t know whichside is positive (+) and whichside is negative (-), then arbi-trarily connect the RED test leadto one side and the BLACK tothe other. The multimeter auto-matically senses polarity and willdisplay a minus (-) sign whennegative polarity is measured. Ifyou switch the RED and BLACKtest leads, positive polarity willnow be indicated on the display.Measuring negative voltagescauses no harm to the multim-eter.

5. Turn multimeter rotary switchto desired voltage range.

If the approximate voltage is un-known, start at the largest voltagerange and decrease to the appro-priate range as required. (SeeSetting the Range on page 6)

6. View reading on display - Noterange setting for correct units.

NOTE: 200mV = 0.2V

Measuring AC VoltageThis multimeter can be used to mea-sure AC voltages in the range from0 to 500V.

To measure AC Voltages (see Fig. 8):

Red Black

Fig. 8

Red

Black

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Fig. 9



4. Turn multimeter rotary switchto 200Ω range.

Touch RED and BLACK multim-eter leads together and viewreading on display.

Display should read typically0.2Ω to 1.5Ω.

If display reading was greaterthan 1.5Ω, check both ends oftest leads for bad connections.If bad connections are found,replace test leads.

5. Connect RED and BLACK testleads across componentwhere you want to measureresistance.

When making resistance mea-surements, polarity is not im-portant. The test leads just haveto be connected across the com-ponent.

6. Turn multimeter rotary switchto desired OHM range.

If the approximate resistance isunknown, start at the largest OHMrange and decrease to the ap-propriate range as required. (SeeSetting the Range on page 6)

RedBlack

UnknownResistance



3. Connect RED test lead to oneside of voltage source.

4. Connect BLACK test lead to otherside of voltage source.

5. Turn multimeter rotary switchto desired voltage range.

If the approximate voltage is un-known, start at the largest voltagerange and decrease to the appro-priate range as required. (SeeSetting the Range on page 6)

6. View reading on display.

NOTE: 200mV = 0.2V

Measuring ResistanceResistance is measured in electricalunits called ohms (Ω). The digitalmultimeter can measure resistancefrom 0.1Ω to 20MΩ (or 20,000,000ohms). Infinite resistance is shownwith a “1” on the left side of display(See Setting the Range on page 6).You can use this multimeter to do anyresistance measurement called outin the vehicle service manual. Test-ing ignition coils, spark plug wires,and some engine sensors are com-mon uses for the OHMS (Ω) function.

To measure Resistance (see Fig. 9):

1. Turn circuit power OFF.

To get an accurate resistancemeasurement and avoid possibledamage to the digital multimeterand electrical circuit under test,turn off all electrical power in thecircuit where the resistance mea-surement is being taken.

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NOTE: 2KΩ = 2,000Ω; 2MΩ =2,000,000Ω

If you want to make precise re-sistance measurements, thensubtract the test lead resistancefound in Step 4 above from thedisplay reading in Step 7. It is agood idea to do this for resis-tance measurements less than10Ω.

Measuring DC CurrentThis multimeter can be used to mea-sure DC current in the range from 0 to10A. Unlike voltage and resistancemeasurements where the multimeteris connected across the componentyou 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

Black

Red

ElectricalDevice

DCVoltageSource

Fig. 11

Black

Red

ElectricalDevice

DCVoltageSource

To measure DC Current (see Figs.10 & 11):


2. Insert RED test lead into "10A"test lead jack or "mA" test leadjack.

3. Disconnect or electricallyopen circuit where you wantto measure current.

This is done by:

• Disconnecting wiring harness.

• Disconnect ing wire fromscrew-on type terminal.

• Unsolder lead from componentif working on printed circuitboards.

• Cut wire if there is no otherpossible way to open electri-cal circuit.

4. Connect RED test lead to oneside of disconnected circuit.

5. Connect BLACK test lead toremaining side of discon-nected circuit.

6. Turn multimeter rotary switchto 10A DC position, 200mA or200µA position.


If minus (-) sign appears on dis-play, then reverse RED andBLACK test leads.

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Fig. 12

leads across diode and viewdisplay.

Display will show one of threethings:

• A typical voltage drop ofaround 0.7V.

• A voltage drop of 0 volts.

• A “1” will appear indicating themultimeter is overranged.

7. Switch RED and BLACK testleads and repeat Step 6.

8. Test Results

If the display showed:

• A voltage drop of 0 volts inboth directions, then the diodeis shorted and needs to bereplaced.

• A “1” appears in both direc-tions, then the diode is an opencircuit and needs to be re-placed.

• The diode is good if the dis-play reads around 0.5V–0.7Vin one direction and a “1” ap-pears in the other directionindicating the multimeter isoverranged.

Testing DiodesA diode is an electrical componentthat allows current to only flow in onedirection. When a positive voltage,generally greater than 0.7V, is ap-plied to the anode of a diode, thediode will turn on and allow current toflow. If this same voltage is applied tothe cathode, the diode would remainoff and no current would flow. There-fore, in order to test a diode, you mustcheck 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):

Anode Cathode

Black

Red



3. Turn multimeter rotary switchto function.

4. Touch RED and BLACK testleads together to test continu-ity.

Check display – should reset to0.00.

5. Disconnect one end of diodefrom circuit.

Diode must be totally isolatedfrom circuit in order to test itsfunctionality.

6. Connect RED and BLACK test

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Fig. 13

BlackRed BlackRed

Testing 1.5V, 9V and12V BatteriesTest Procedure (see Fig. 13):



3. Turn multimeter rotary switchto 1.5V, 9V or 12V range.

4. Connect RED test lead to posi-tive (+) terminal of battery.

5. Connect BLACK test lead tonegative (-) terminal of battery.


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Section 2. Automotive TestingThe digital multimeter is a very use-ful tool for trouble-shooting automo-tive electrical systems. This sectiondescribes how to use the digital mul-timeter to test the starting and charg-ing system, ignition system, fuelsystem, and engine sensors. Thedigital multimeter can also be usedfor general testing of fuses, switches,solenoids, and relays.

General TestingThe digital multimeter can be usedto test fuses, switches, solenoids,and relays.

Testing FusesThis test checks to see if a fuse isblown.

To test Fuses (see Fig. 14):

Fig. 15

Red

Typical "Push"Button Switch



3. Turn multimeter rotary switchto 2000Ω function.

4. Connect BLACK test lead toone side of switch.

5. Connect RED test lead to otherside of switch.

• If the reading is zero - Theswitch is closed.

• If the reading is overrange -The switch is open.

6. Operate switch.

• If the reading is zero - Theswitch is closed.




4. Connect RED and BLACK testleads to opposite ends of fuse.

• If the reading is zero - Fuse isgood.

Fig. 14

Red Black

Fuse

Black

• If the reading is overrange -Fuse is blown and needs to bereplaced.

NOTE: Always replace blownfuses with same type and rating.

Testing SwitchesThis test checks to see if a switch“Opens” and “Closes” properly.

To test Switches (see Fig. 15):

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• Typical solenoid / relay coil re-sistances are 200Ω or less.

• Refer to vehicle service manualfor the device's resistancerange.

If meter overranges, turn multi-meter rotary switch to next higherrange. (see Setting the Rangeon 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 withinmanufacturers specifications.

• Display reads overrange onevery ohms range indicating anopen circuit.

NOTE: Some relays and sole-noids have a diode placed acrossthe coil. To test this diode seeTesting Diodes on page 11.




Most solenoids and relay coilresistances are less than 200Ω.

4. Connect BLACK test lead toone side of coil.

5. Connect RED test lead to otherside of coil.

• If the reading is overrange -The switch is open.

7. Repeat Step 6 to verify switchoperation.

Testing Solenoidsand RelaysThis test checks to see if a solenoidor relay has a broken coil. If the coiltests good, it is still possible that therelay or solenoid is defective. Therelay can have contacts that arewelded or worn down, and the sole-noid may stick when the coil is ener-gized. This test does not check forthose potential problems.

To test Solenoids and Relays (seeFig. 16):

Relay orSolenoid

Red

Black

Fig. 16

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Starting/Charging System TestingThe starting system “turns over” the engine. It consists of the battery, startermotor, 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, andassociated wiring and connections. The digital multimeter is a useful tool forchecking the operation of these systems.

No Load Battery TestBefore you do any starting/chargingsystem checks, you must first testthe battery to make sure it is fullycharged.

Test Procedure (see Fig. 17):

Fig. 17

Black

Red

1. Turn Ignition Key OFF.

2. Turn ON headlights for 10 sec-onds to dissipate battery sur-face charge.



5. Disconnect positive (+) batterycable.



8. Turn multimeter rotary switchto 20V DC range.


10. Test Results.

Compare display reading in Step9 with the following chart.

PercentVoltage Battery is Charged

12.60Vor greater 100%

12.45V 75%

12.30V 50%

12.15V 25%

If battery is not 100% charged, thencharge it before doing anymore start-ing/charging system tests.

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3. Insert RED test lead into "10A"(or "mA") test lead jack.

4. Disconnect positive (+) batterycable.

5. Connect RED test lead to posi-tive (+) battery terminal.

6. Connect BLACK test lead topositive (+) battery cable.

NOTE: Do not start vehicle dur-ing this test, because multimeterdamage may result.

7. Turn multimeter rotary switchto 10A DC (or 200 mA) posi-tion.


• Typical current draw is 100mA.(1mA = 0.001A)

• Refer to vehicle service manualfor manufacturers specific En-gine Off Battery Current Draw.

NOTE: Radio station presetsand clocks are accounted for inthe 100mA typical current draw.

9. Test Results.

Normal Current Draw: Displayreading in Step 8 is within manu-facturers specifications.

Excessive Current Draw:

- Display reading in Step 8 iswell outside manufacturersspecifications.

- Remove Fuses from fuse boxone at a time until source ofexcessive current draw is lo-cated.

- Non-Fused circuits such asheadlights, relays, and sole-noids should also be checkedas possible current drains onbattery.

- When source of excessive cur-rent drain is found, service asnecessary.

BlackRed

Fig. 18

Engine Off BatteryCurrent DrawThis test measures the amount ofcurrent being drawn from the batterywhen the ignition key and engine areboth off. This test helps to identifypossible 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, anddome lights are all OFF.

(See Fig. 18)

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7. Crank engine for 15 secondscontinuously while observingdisplay.

8. Test Results.

Compare display reading in Step7 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 toabove voltage vs. temperature chart,then cranking system is normal.

If voltage on display does not corre-spond to chart, then it is possiblethat the battery, battery cables, start-ing system cables, starter solenoid,or starter motor are defective.

RedBlack

Cranking Voltage -Battery Load TestThis test checks the battery to see if itis delivering enough voltage to thestarter motor under cranking conditions.


Fig. 19

1. Disable ignition system so ve-hicle won’t start.

Disconnect the primary of theignition coil or the distributor pick-up coil or the cam/crank sensorto disable the ignition system.Refer to vehicle service manualfor disabling procedure.




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5. Turn multimeter rotary switchto 200mV DC range.

If multimeter overranges, turn mul-timeter rotary switch to the2000mV DC range. (See Settingthe Range on page 6)

6. Crank engine until steadyreading is on display.

• Record results at each pointas displayed on multimeter.

• Repeat Step 4 & 5 until allpoints are checked.

7. Test Results –

Estimated Voltage Drop ofStarter Circuit Components

Component Voltage

Switches 300mV

Wire or Cable 200mV

Ground 100mV


1. Disable ignition system so ve-hicle won’t start.

Disconnect the primary of theignition coil or the distributor pick-up coil or the cam/crank sensorto disable the ignition system.Refer to vehicle service manualfor disabling procedure.



4. Connect test leads.

Refer to Typical Cranking Volt-age Loss Circuit (Fig. 20).

• Connect RED and BLACK testleads alternately between 1 & 2,2 & 3, 4 & 5, 5 & 6, 6 & 7, 7 & 9,8 & 9, and 8 & 10.

Red Black

Fig. 20 Typical Cranking VoltageLoss Circuit Solenoid

This is a representativesample of one type ofcranking circuit. Your vehiclemay use a different circuitwith different components orlocations. Consult yourvehicle service manual.

Starter

Voltage DropsThis test measures the voltage drop across wires, switches, cables, solenoids,and connections. With this test you can find excessive resistance in the startersystem. This resistance restricts the amount of current that reaches the startermotor resulting in low battery load voltage and a slow cranking engine at starting.

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Component Voltage

Battery CableConnectors 50mV

Connections 0.0V

• Compare voltage readings inStep 6 with above chart.

• If any voltages read high, inspectcomponent and connection fordefects.

• If defects are found, service asnecessary.

Fig. 21

RedBlack

7. Turn off all accessories andview reading on display.

• Charging system is normal ifdisplay reads 13.2 to 15.2 volts.

• If display voltage is not be-tween 13.2 to 15.2 volts, thenproceed to Step 13.

8. Open throttle and Hold enginespeed (RPM) between 1800 and2800 RPM.

Hold this speed through Step 11 -Have an assistant help holdspeed.


Voltage reading should notchange from Step 7 by morethan 0.5V.

10. Load the electrical system byturning on the lights, wind-shield wipers, and setting theblower fan on high.


Voltage should not drop downbelow about 13.0V.

12. Shut off all accessories, re-turn engine to curb idle andshut off.






6. Start engine - Let idle.

Charging System Voltage TestThis test checks the charging sys-tem to see if it charges the batteryand provides power to the rest of thevehicles electrical systems (lights,fan, radio etc).


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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 Steps7, 9, and 11 were different thenshown here or in vehicle ser-vice manual, then check for aloose alternator belt, defectiveregulator or alternator, poorconnections, or open alterna-tor field current.

• Refer to vehicle service manualfor further diagnosis.

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Ignition System TestingThe ignition system is responsible for providing the spark that ignites the fuel inthe cylinder. Ignition system components that the digital multimeter can test arethe primary and secondary ignition coil resistance, spark plug wire resistanceand reluctance pick-up coil sensors.

Ignition Coil TestingThis test measures the resistanceof the primary and secondary of anignition coil. This test can be usedfor distributorless ignition systems(DIS) provided the primary and sec-ondary ignition coil terminals areeasily accessible.

Test Procedure:

1. If engine is HOT let it COOLdown before proceeding.

2. Disconnect ignition coil fromignition system.

3. Insert BLACK test lead intoCOM test lead jack (see Fig.22).



6. Touch RED and BLACK multi-meter leads together and viewreading on display.

7. 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.

• Refer to vehicle service manualfor location of primary ignitioncoil terminals.


Subtract test lead resistance foundin Step 6 from above reading.

9. If vehicle is DIS, repeat Steps 7and 8 for remaining ignitioncoils.

10. Test Results - Primary Coil

• Typical resistance range of pri-mary ignition coils is 0.3 - 2.0Ω.

• Refer to vehicle service manualfor your vehicles resistance range.

Typical CylindricalIgnition Coil

BlackRed

PrimaryCoil

SecondaryCoil

Fig. 2211.Turn multi-

meter rotaryswitch to200kΩ range(see Fig. 23).

12.Move REDtest lead tosecondary ig-nition coil ter-minal.

• Refer to ve-hicle service

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manual for location of second-ary ignition coil terminal.

• Verify BLACK test lead is con-nected to primary ignition coilnegative (-) terminal.


14. If vehicle is DIS, connect testleads to terminals of the sec-ondary ignition coil. Repeatfor remaining ignition coils.

15. Test Results - Secondary Coil

• Typical resistance range ofsecondary ignition coils is6.0kΩ - 30.0kΩ.

• Refer to vehicle servicemanual for your vehicles re-sistance range.

Fig. 23

Typical CylindricalIgnition Coil

Black

Red

PrimaryCoil

SecondaryCoil

16. Repeat test procedure for aHOT ignition coil.

NOTE: It is a good idea to testignition coils when they are bothhot and cold, because the resis-tance of the coil could changewith temperature. This will alsohelp in diagnosing intermittentignition system problems.

17. Test Results - Overall

Good Ignition Coil: Resistancereadings in Steps 10, 15 and 16were within manufacturers speci-fication.

Bad Ignition Coil: Resistancereadings in Steps 10, 15 and 16are not within manufacturersspecification.

23

Ignition System WiresThis test measures the re-sistance of spark plug andcoil tower wires while theyare being flexed. This testcan be used fordistributorless ignition sys-tems (DIS) provided the sys-tem does not mount the igni-tion coil directly on the sparkplug.

Test Procedure:

1. Remove ignition sys-tem wires one at a time fromengine.

• Always grasp ignition systemwires on the boot when removing.

• Twist the boots about a halfturn while pulling gently to re-move them.

• Refer to vehicle service manualfor ignition wire removal pro-cedure.

• Inspect ignit ion wires forcracks, chaffed insulation, andcorroded ends.

NOTE: Some Chrysler productsuse a “positive-locking” terminalelectrode spark plug wire. Thesewires can only be removed frominside the distributor cap. Dam-age may result if other means ofremoval are attempted. Refer tovehicle service manual for pro-cedure.

NOTE: Some spark plug wireshave sheet metal jackets withthe following symbol: . Thistype of plug wire contains an “airgap” resistor and can only bechecked with an oscilloscope.

2. Insert BLACK test lead intoCOM test lead jack (see Fig.24).


4. Connect RED test lead to oneend of ignition wire andBLACK test lead to other end.

5. Turn multimeter rotary switchto 200KΩ range.

6. View reading on display whileflexing ignition wire and bootin several places.

• Typical resistance range is3KΩ to 50KΩ or approximately10KΩ per foot of wire.

• Refer to vehicle service manualfor your vehicles resistancerange.

• As you flex ignition wire, thedisplay should remain steady.

7. Test Results

Good Ignition Wire: Displayreading is within manufacturersspecification and remains steadywhile wire is flexed.

Bad Ignition Wire: Display read-ing erratically changes as igni-tion wire is flexed or display read-ing is not within manufacturersspecification.

Fig. 24

Black

Spark Plug Wire

Red

24

Reluctance sensors are used when-ever the vehicle computer needs toknow speed and position of a rotat-ing object. Reluctance sensors arecommonly used in ignition systemsto determine camshaft and crank-shaft position so the vehicle com-puter knows the optimum time to firethe ignition coil(s) and turn on thefuel injectors. This test checks thereluctance sensor for an open orshorted coil. This test does not checkthe air gap or voltage output of thesensor.


ReluctanceSensor

RedBlack



3. Connect RED test lead to ei-ther sensor pin.

4. Connect BLACK test lead toremaining sensor pin.

ReluctorRing

Magnet


6. View reading on display whileflexing sensor wires in sev-eral places.

• Typical resistance range is 150- 1000Ω.

• Refer to vehicle service manualfor your vehicles resistancerange.

• As you flex sensor wires, thedisplay should remain steady.

7. Test Results

Good Sensor: Dis-play reading is withinmanufacturers speci-fication and remainssteady while sensorwires are flexed.

Bad Sensor: Displayreading erraticallychanges as sensorwires are flexed ordisplay reading is notwithin manufacturersspecification.

Fig. 25

Magnetic Pick-Up Coils – Reluctance Sensors

25

Fuel System TestingThe requirements for lower vehicle emissions has increased the need formore 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 controlfuel and further lower emissions. The digital multimeter can be used tomeasure fuel injector resistance.

Measuring Fuel Injector ResistanceFuel injectors are similar to sole-noids. They contain a coil that isswitched ON and OFF by the ve-hicle computer. This test measuresthe resistance of this coil to makesure it is not an open circuit. Shortedcoils can also be detected if thespecific manufacturer resistance ofthe fuel injector is known.


Fig. 26Typical

Fuel Injector

Black Red




Touch RED and BLACK multim-eter leads together and viewreading on display.

Display should read typically 0.2 -1.5Ω.

If display reading was greaterthan 1.5Ω, check both ends oftest leads for bad connections. Ifbad connections are found, re-place test leads.

4. Disconnect wiring harnessfrom fuel injector - Refer tovehicle service manual for pro-cedure.

5. Connect RED and BLACKtest leads across fuel in-jector pins.

Make sure you connect testleads across fuel injectorand not the wiring harness.

6. Turn multimeter rotaryswitch to desired OHMrange.

If the approximate resis-tance is unknown, start atthe largest OHM range anddecrease to the appropri-

ate range as required. (see Set-ting the Range on page 6)


• If display reading is 10Ω orless, subtract test lead resis-tance found in Step 3 fromabove reading.

• Compare reading to manufac-turers specifications for fuel in-jector coil resistance.

26

• This information is found invehicle service manual.

8. Test Results

Good Fuel Injector resistance:Resistance of fuel injector coil iswithin manufacturers specifica-tions.

Bad Fuel Injector resistance: Re-sistance of fuel injector coil isnot 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 ispossible that the fuel injector isclogged or dirty and that is caus-ing your driveability problem.

27

Testing Engine SensorsIn the early 1980’s, computer controls were installed in vehicles to meetFederal Government regulations for lower emissions and better fuel economy.To do its job, a computer-controlled engine uses electronic sensors to findout what is happening in the engine. The job of the sensor is to takesomething the computer needs to know, such as engine temperature, andconvert it to an electrical signal which the computer can understand. Thedigital multimeter is a useful tool for checking sensor operation.

The Oxygen Sensor produces a volt-age or resistance based on theamount of oxygen in the exhauststream. A low voltage (high resis-tance) indicates a lean exhaust (toomuch oxygen), while a high voltage(low resistance) indicates a rich ex-haust (not enough oxygen). Thecomputer uses this voltage to ad-just the air/fuel ratio. The two typesof O2 Sensors commonly in use areZirconia and Titania. Refer to illus-tration for appearance differencesof the two sensor types.


1. If engine is HOT, let it COOLdown before proceeding.

Titania-TypeOxygen Sensor

Zirconia-TypeOxygen Sensor

Exposedflat element

Flutes

Rich Lean

Red

2. Remove Oxygen Sensor fromvehicle.



1-wire or 3-wire: Ground is sensor housing

2-wire or 4-wire: Ground is in sensor wiringharness

Ground

Fig. 27

Oxygen (O2) Type Sensors

Black

28

5. Test heater circuit.

• If sensor contains 3 or morewires, then your vehicle uses aheated O2 sensor.

• Refer to vehicle service manualfor location of heater pins.

• Connect RED test lead to ei-ther heater pin.

• Connect BLACK test lead toremaining heater pin.

• Turn multimeter rotary switchto 200Ω range.

• View reading on display.

• Compare reading tomanufacturer's specification invehicle service manual.

• Remove both test leads fromsensor.

6. Connect BLACK test lead tosensor GROUND pin.

• If sensor is 1-wire or 3-wire, thenGROUND is sensor housing.

• If sensor is 2-wire or 4-wire,then GROUND is in sensor wir-ing harness.

• Refer to vehicle service manualfor Oxygen Sensor wiring dia-gram.

7. Connect RED test lead to sen-sor SIGNAL pin.

8. Test Oxygen Sensor.

• Turn multimeter rotary switchto...

– 2000mV range for ZirconiaType Sensors.

– 200KΩ range for Titania TypeSensors.

• Light propane torch.

• Firmly grasp sensor with a pairof locking pliers.

• Thoroughly heat sensor tip ashot as possible, but not “glow-ing.” Sensor tip must be at660°F to operate.

• Completely surround sensor tipwith flame to deplete sensor ofoxygen (Rich Condition).

• Multimeter display shouldread...

– 600mV or greater for Zirco-nia Type Sensors.

– an Ohmic(Resistance) valuefor Titania Type Sensors.Reading will vary with flametemperature.

• While still applying heat to sen-sor, move flame such that oxy-gen can reach sensor tip (LeanCondition).

• Multimeter display shouldread...

– 400mV or less for ZirconiaType Sensors.

– an overrange condition forTitania Type Sensors. (SeeSetting the Range on page 6.)

9. Repeat Step 8 a few times toverify results.

10. Extinguish Flame, let sensorcool, and remove test leads.

11. Test Results.

Good Sensor:

• Heater Circuit resistance iswithin manufacturer's specifi-cation.

• Oxygen Sensor output signalchanged when exposed to arich and lean condition.

Bad Sensor:

• Heater Circuit resistance is notwithin manufacturer's specifi-cation.

29

Red

Black

Hair Dryer

TypicalIntake Air

TemperatureSensor


4. Disconnect wiring harnessfrom sensor.

5. If testing Intake Air Tempera-ture Sensor - Remove it fromvehicle.

All other temperature sensorscan remain on vehicle for test-ing.

6. Connect RED test lead to ei-ther sensor pin.

7. Connect BLACK test lead toremaining sensor pin.

8. Turn multimeter rotary switchto desired OHM range.If the approximate resistance isunknown, start at the largest OHMrange and decrease to the appro-priate range as required. (SeeSetting the Range on page 6.)

9. View and record reading ondisplay.

10. Disconnect multimeter testleads from sensor and recon-nect sensor wiring.This step does not apply to in-take air temperature sensors. Forintake air temperature sensors,leave multimeter test leads stillconnected to sensor.

11. Heat up sensor.

If testing Intake Air TemperatureSensor:• To heat up sensor dip sensor

tip into boiling water, or...

• Heat tip with a lighter if sensortip is metal or a hair dryer ifsensor tip is plastic.

• View and record smallest read-ing on display as sensor isheated.

• You may need to decrease the

• Oxygen Sensor output signaldid not change when exposedto a rich and lean condition.

• Oxygen sensor output voltagetakes longer than 3 secondsto switch from a rich to a leancondition.

Temperature TypeSensorsA temperature sensor is a thermistoror a resistor whose resistancechanges with temperature. The hot-ter the sensor gets, the lower theresistance becomes. Typical ther-mistor applications are engine cool-ant sensors, intake air temperaturesensors, transmission fluid tempera-ture sensors, and oil temperaturesensors.


Fig. 28

1. If engine is HOT let it COOLdown before proceeding.

Make sure all engine and trans-mission fluids are at outside airtemperature before proceedingwith this test!


30

range to get a more accuratereading.

For all other temperature sen-sors:

• Start engine and let idle untilupper radiator hose is warm.

• Turn ignition key OFF.

• Disconnect sensor wiring har-ness and reconnect multimetertest leads.

• View and record reading ondisplay.

12. Test Results.

Good Sensor:

• Temperature sensors HOT re-sistance is at least 300Ω lessthan its COLD resistance.

• The key point is that the COLDresistance decreases with in-creasing temperature.

Bad Sensor:

• There is no change betweenthe temperature sensors HOTresistance from the COLD re-sistance.

• The temperature sensor is anopen or a short circuit.

Position TypeSensorsPosition sensors are potentiometersor a type of variable resistor. Theyare used by the computer to deter-mine position and direction of move-ment of a mechanical device. Typi-cal position sensor applications arethrottle position sensors, EGR valveposition sensors, and vane air flowsensors.




3. Disconnect wiring harnessfrom sensor.

4. Connect Test Leads.

• Connect RED test lead to sen-sor POWER pin.

• Connect BLACK test lead tosensor GROUND pin.

• Refer to vehicle service manualfor location of sensor POWERand GROUND pins.

5. Turn multimeter rotary switchto 20KΩ range.

Fig. 29 Typical Toyota ThrottlePosition Sensor

Red Black

POWER GROUND

SIGNAL IDLE SWITCH

31

6. View and record reading ondisplay.

• Display should read some re-sistance value.

• If multimeter is overranging, ad-just the range accordingly. (SeeSetting the Range on page 6.)

• If multimeter overranges on larg-est range, then sensor is anopen circuit and is defective.

7. Move RED test lead to sensorSIGNAL pin.

• Refer to vehicle service manualfor location of sensor SIGNAL pin.

8. Operate Sensor.

Throttle Position Sensor:

• Slowly move throttle linkagefrom closed to wide open posi-tion.

• Depending on hook-up, the dis-play reading will either in-crease or decrease in resis-tance.

• The display reading should ei-ther start at or end at the ap-proximate resistance valuemeasured in Step 6.

• Some throttle position sensorshave an Idle or Wide OpenThrottle (WOT) switch in addi-tion to a potentiometer.

• To test these switches, followthe Testing Switches test pro-cedure on page 13.

• When you are told to operateswitch, then move throttle link-age.

Vane Air Flow Sensor:

• Slowly open vane “door” fromclosed to open by pushing on itwith a pencil or similar object.This will not harm sensor.

• Depending on hook-up, the dis-play reading will either increaseor decrease in resistance.

• The display reading should ei-ther start at or end at the ap-proximate resistance value mea-sured in Step 6.

• Some vane air flow sensorshave an idle switch and an in-take air temperature sensor inaddition to a potentiometer.

• To test idle switch see TestingSwitches on page 13.

• When you are told to operateswitch, then open vane “door”.

• To test intake air temperaturesensor see Temperature TypeSensors on page 29.

EGR Valve Position

• Remove vacuum hose fromEGR valve.

• Connect hand vacuum pumpto EGR valve.

• Gradually apply vacuum toslowly open valve. (Typically,5 to 10 in. of vacuum fully opensvalve.)

• Depending on hook-up, the dis-play reading will either increaseor decrease in resistance.

• The display reading should ei-ther start at or end at the ap-proximate resistance value mea-sured in Step 6.

9. Test Results.

Good Sensor: Display read-ing gradually increases or de-creases in resistance as sensoris opened and closed.

Bad Sensor: There is no changein resistance as sensor is openedor closed.

32

ElectricalSpecifications

DC VoltsRange: 200mV, 2000mV, 20V, 200VAccuracy : ± (0.5% rdg + 2 dgts)

Range: 500VAccuracy: ±(0.8% rdg + 2 dgts)

AC VoltsRange: 200V, 500VAccuracy : ± (1.2% rdg + 10 dgts)

DC CurrentRange: 200µAAccuracy: ±(1.0% rdg + 2 dgts)

Range: 200mAAccuracy: ±(1.2% rdg + 2 dgts)

Range: 10AAccuracy: ±(2.0% rdg + 5 dgts)

ResistanceRange: 200ΩAccuracy: ±(0.8% rdg + 5 dgts)

Range: 2000Ω, 20KΩ, 200KΩAccuracy: ±(0.8% rdg + 2 dgts)

Range: 20MΩAccuracy: ±(1.0% rdg + 5 dgts)

Battery TestRange: 1.5V, 9V, 12VAccuracy: ±(10% rdg + 2 dgts)

Diode TestResolution: 1mV

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