Actron CP7676 User Manual

Digital Multimeter

OPERATING

INSTRUCTIONS

Instrucciones en español,

páginas 37-72

Index

Safety Precautions .............................2

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

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

Electrical Specifications ................... 35

Warranty ........................................... 72

1. Multimeter Basic Functions

Functions and Display Definitions ............ 4

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

Battery Replacement ................................ 7

Measuring AC Voltage ..............................7

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

Measuring Resistance .............................. 8

Testing for Continuity ................................ 9

Testing Diodes .......................................... 9

Measuring Engine RPM (TACH) ............ 10

Measuring Dwell ...................................... 11

2. Automotive Testing with the CP7676

General Testing .......................................13

- Testing Fuses ....................................... 13

- Testing Switches .................................. 13

- Testing Solenoids and Relays ............. 14

Starting / Charging System Testing............ 15

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

- Cranking Voltage/Battery Load Test.... 16

- Voltage Drops ....................................... 17

- Charging System Voltage Test ............ 18

OHMS

OFF

P7676

RPM

CYL

X10

CYL

DWELL

CP7676

COM

Ignition System Testing ..............................20

- Ignition Coil Testing .............................. 20

- Ignition System Wires ..........................22

- Hall Effect Sensors/Switches ..............23

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

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

- Ignition Coil Switching Action ..............25

Fuel System Testing ................................... 26

- Testing Mixture Control Solenoid

on Feedback Carburetor ......................26

- Measuring Fuel Injector Resistance .... 27

Testing Engine Sensors ..............................28

- Oxygen (O2) Type Sensors ..................28

- Temperature Type Sensors .................. 30

- Position Type Sensors  Throttle and EGR Valve Position,

Vane Air Flow........................................ 31

- Manifold Absolute Pressure (MAP) and Barometric Pressure (BARO) Sensors ..32

- Mass Air Flow (MAF) Sensors .............34

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 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 disconnecting electrical components, unless

otherwise instructed.

 Always follow vehicle manufacturers warnings, cautions and service procedures.

CAUTION:

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 unexpectedly, resulting in personal injury. Note that the air bag can still open up several minutes after the ignition key is off (or even if the vehicle battery is disconnected) because of a special energy reserve module.

All information, illustrations and specifications contained in this manual are based on the latest information available from industry sources at the time of publication. No warranty (expressed or implied) can be made for its accuracy or completeness, nor is any responsibility assumed by Actron Manufacturing Co. or anyone connected with it for loss or damages suffered through reliance on any information contained in this manual or misuse of accompanying product. A ctron Manufacturing Co. reserves the right to make changes at any time to this manual or accompanying product without obligation to notify any person or organization of such changes.

Vehicle Service Manual  Sources For Service Information

The following is a list of sources to obtain vehicle service information for your specific vehicle.  Contact your local Automotive Dealership Parts Department.  Contact local retail auto parts stores for aftermarket vehicle service information.  Contact your local library. Libraries often allow you to check-out automotive service manuals.

Do a Thorough Visual Inspection

Do a thorough visual and hands-on underhood inspection before starting any diagnostic procedure! You can find the cause of many problems by just looking, thereby saving yourself a lot of time.  Has the vehicle been serviced recently? Sometimes things get reconnected in the wrong place,

or not at all.

 Dont take shortcuts. Inspect hoses and wiring which may be difficult to see due to location.

 Inspect the air cleaner and ductwork for defects.

 Check sensors and actuators for damage.

 Inspect ignition wires for:

- Damaged terminals.

- Split or cracked spark plug boots

- Splits, cuts or breaks in the ignition wires and insulation.

 Inspect all vacuum hoses for:

- Correct routing. Refer to vehicle service manual, or Vehicle Emission Control Information(VECI) decal located in the engine compartment.

- Pinches and kinks.

- Splits, cuts or breaks.

 Inspect wiring for:

- Contact with sharp edges.

- Contact with hot surfaces, such as exhaust manifolds.

- Pinched, burned or chafed insulation.

- Proper routing and connections.

 Check electrical connectors for:

- Corrosion on pins.

- Bent or damaged pins.

- Contacts not properly seated in housing.

- Bad wire crimps to terminals.

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.

OFF

200K

750

200

20K

200

20M

OHMS

COM

CYL

750V AC 200V DC

CYL

CP7676

RPM X10

CYL

DWELL

Alligator Clip Adapters

Some multimeter tests and measurements are more easily done using alligator clips instead of test prods. For these tests, push the crimp end of the alligator clip onto the test prod. If the crimp on the alligator clip becomes loose, then remove the alligator clip from the test prod and re-crimp using a pair of pliers.

Functions and Display Definitions

(Refer to Digital Multimeter illustration on facing page)

1. ROTARY SWITCH

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

2. RPM X 10

This Function is used for measuring engine speed (RPM).

3. DWELL

This Function is used for measuring DWELL on distributor ignition systems, and solenoids.

4. DIODE CHECK

This Function is used to check whether a diode is good or bad.

5. TEST LEAD JACKS

BLACK Test Lead is always inserted in the COM test lead jack. RED Test Lead is always inserted in the

Always connect TEST LEADS to the multimeter before connecting them to the circuit under test!!

6. OHMS

This Function is used for measuring the resistance of a component in an electrical circuit in the range of 0.1Ω to 20MΩ. (Ω is the electrical symbol for Ohms)

7. DC VOLTS

This Function is used for measuring DC (Direct Current) Voltages in the range of 0 to 200V.

test lead jack.

8. AC VOLTS

This Function is used for measuring AC (Alternating Current) Voltages in the range of 0 to 750V.

9. DISPLAY

Used to display all measurements and multimeter information.

Low Battery  If LO BAT appears in the upper left corner of the display, then

replace the internal 9V battery. (see Battery Replacement on page 7.)

Overrange Indication  If 1 or -1 appears on the left side of the display, then the multimeter is set to a range that is too small for the present measurement being taken. Increase the range

until this disappears. If it does not disappear after all the ranges for a particular function have been tried, then the value being measured is too large for the multimeter to measure. (see Setting the Range on page 6.)

Zero Adjustment

The multimeter will automatically zero on the Volts, Amps, and RPM 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 reversed.

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 multimeter 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 Battery Voltage (See Fig. 1)

Fig. 1

CP7676

OFF

750

200

20M

2M 200K

20K

OHMS

Lets assume the multimeter is connected to the battery and set to the 20V range. The display reads 12.56. This means there is

12.56V across the battery terminals.

COM

CYL

200

750V AC 200V DC

Red

Black

Fig. 2

Now assume we set the multimeter to the 2V 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 range should be increased until a value is shown on the display. If you are in the highest range and the multimeter is still 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?

The multimeter should be set in the lowest possible range without overranging. EXAMPLE: Measuring an unknown resistance Lets assume the multimeter is connected to an engine coolant sensor with unknown resistance. (See Fig. 3) Start by setting the multimeter to the largest OHM range. The display reads 0.0Ω or a short circuit.

Fig. 3

CP7676

OFF

20M

2M 200K

OHMS

750

200

20K

COM

CYL

Red

ELL

200

750V AC 200V DC

Black

20M

2M 200K

OHMS

CP7676

OFF

750

200

20K

COM

CYL

ELL

200

750V AC 200V DC

Red

Black

This sensor cant be shorted so reduce the range setting until you get a value of resistance. At the 200KΩ range the multimeter measured a value of 4.0. This means there is 4KΩ of resistance across the engine coolant sensor terminals. (See Fig. 4) If we change the multimeter to the 20KΩ range (See Fig. 5) the display shows a value of 3.87KΩ. The actual value of resistance is

20M

OHMS

2M 200K

Fig. 4

Battery Replacement

Important: A 9 Volt battery must be installed before using the digital multimeter. (See

CP7676

OFF

750

200

20K

COM

CYL

Red

200

750V AC 200V DC

Black

procedure below for installation.)

Battery Replacement

1. Turn multimeter rotary switch to OFF position.

2. Remove test leads from multimeter.

3. Remove three screws from back of multimeter.

4. Remove back cover.

5. Install a new 9 Volt battery.

6. Re-assemble multimeter.

3.87KΩ and not 4KΩ that was

Fig. 5

measured in the 200KΩ range. This is very important because if the manufacturer specifications say that the sensor should read 3.8-

3.9KΩ at 70°F then on the 200KΩ range the sensor would be defective, but at the 20KΩ range it would

20M

2M 200K

OHMS

CP7676

OFF

750

200

20K

COM

CYL

ELL

200

750V AC 200V DC

test good. Now set the multimeter to the 2KΩ range. (See Fig. 6) The display will indicate an overrange condition because 3.87KΩ is larger than 2KΩ. This example shows that by decreasing the range you increase the accuracy of

Fig. 6

your measurement. When you change the range, you change the location of the decimal point. This changes the accuracy of the measurement by either increasing or decreasing the number of digits after the decimal point.

20M

2M 200K

OHMS

CP7676

OFF

750

200

20K

COM

CYL

200

750V AC 200V DC

Measuring AC Voltage

This multimeter can be used to measure AC voltages in the range of 0 to 750V. You can use this multimeter for trouble-shooting household electrical wiring and appliances. To measure AC Voltages:

1. Insert BLACK test lead into the COM test lead jack.

2. Insert RED test lead into the lead jack.

3. Connect RED test lead to either side of AC voltage source.

4. Connect BLACK test lead to remaining side of AC voltage source.

NOTE: Since AC voltages alternate between a positive and negative value, test lead hook-up polarity is not important.

5. Turn multimeter rotary switch to 750 AC V voltage range.

6. View reading on display.

test

Measuring DC Voltage

This multimeter can be used to measure DC voltages in the range from 0 to 200V. You can use this multimeter to do any DC voltage measurement called out in the vehicle service manual. The most common applications are measuring voltage drops, and checking if the correct voltage arrived at a sensor or a particular circuit.

Fig. 7

CP7676

OFF

750

CYL

200

20M

2M 200K

OHMS

To measure DC Voltages (see Fig. 7):

1. Insert BLACK test lead into the COM test lead jack.

2. Insert RED test lead into the test lead jack.

3. Connect RED test lead to positive (+) 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 arbitrarily connect the RED test lead to one side and the BLACK to the other. The multimeter automatically 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 multimeter.

5. Turn multimeter rotary switch to desired voltage range.

If the approximate voltage is unknown, start at the largest voltage range and decrease to the appropriate range as required. (See Setting the Range on page 6)

CYL

20K

CYL

COM

ELL

200

750V AC 200V DC

Red Black

6. View reading on display - Note range setting for correct units.

NOTE: 200mV = 0.2V

Measuring Resistance

Resistance is measured in electrical units called ohms (Ω). The digital multimeter can measure resistance from 0.1Ω to 20MΩ 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). You can use this multimeter to do any resistance measurement called out in the vehicle service manual. Testing ignition coils, spark plug wires, and some engine sensors are common uses for the OHMS (Ω) function. To measure Resistance (see Fig. 8):

Fig. 8

200

COM

750V AC 200V DC

CYL

DWELL

CYL

Unknown

Resistance

Red

20M

2M 200K

20K

OHMS

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 measurement is being taken.

2. Insert BLACK test lead into the COM test lead jack.

3. Insert RED test lead into the lead jack.

4. Turn multimeter rotary switch to 200Ω range.

Touch RED and BLACK multimeter leads together and view reading on display. Display should read typically 0.2Ω to 1.5Ω. If display reading was greater than 1.5Ω, check both ends of test leads for bad connections. If bad connections are found, replace test leads.

Black

test

5. Connect RED and BLACK test leads across component where you want to measure resistance.

When making resistance measurements, polarity is not important. The test leads just have to be connected across the component.

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 appropriate range as required. (See Setting the Range on page 6)

7. View reading on display - Note range setting for correct units.

NOTE: 2KΩ = 2,000Ω; 2MΩ = 2,000,000Ω

If you want to make precise resistance 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 resistance measurements less than 10Ω.

Testing for Continuity

Continuity is a specific type of resistance test to determine if a circuit is open or closed. The multimeter will display circuit resistance. Resistance smaller than 10Ω usually indicates continuity. Continuity checks are usually done when checking for blown fuses, switch operation, and open or shorted wires.

4. Touch RED and BLACK test leads together and view reading on display.

Display should read typically 0.2Ω to 1.5Ω. If display reading was greater than 1.5Ω, 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 want to check for continuity.

View reading on display:

 Continuity - Display reading is less than

10Ω.

 No Continuity - Display reading is greater

than 10Ω.

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 applied 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. Therefore, in order to test a diode, you must check it in both directions (i.e. anode-tocathode, and cathode-to-anode). Diodes are typically found in alternators on automobiles. Performing Diode Test (see Fig. 10):

Fig. 9

20M

2M 200K

20K

OHMS

COM

To measure Continuity (see Fig. 9):

1. Insert BLACK test lead into the COM test lead jack.

2. Insert RED test lead into the test lead jack.

3. Turn multimeter rotary switch to 200Ω range.

CYL

DWELL

200

Black

750V AC 200V DC

Red

Fig. 10

20M

2M 200K

20K

OHMS

Anode

CYL

DWELL

200

COM

750V AC 200V DC

Red

Cathode

Black

1. Insert BLACK test lead into the COM test lead jack.

2. Insert RED test lead into the

test

lead jack.

3. Turn multimeter rotary switch to function.

4. Touch RED and BLACK test leads together to test continuity.

Display reading should be approximately zero volts. If display reads greater than 0.5V, then check both test leads for bad connections. If bad connections are found, replace test leads.

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.

7. Switch RED and BLACK test leads and repeat Step 6.

8. 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 directions, then the

diode is an open circuit and needs to be replaced.

 The diode is good if the display reads

around 0.7V in one direction and a 1 appears in the other direction indicating the multimeter is overranged.

Measuring Engine RPM (TACH)

The CP7676 has a RPM X 10 function for measuring engine speed or RPM. When using the RPM X 10 function, you must multiply the display reading by 10 to get actual RPM. If display reads 200, then the actual engine RPM is 10 times 200 or 2000 RPM.

OFF

750

CYL

200

COM

750V AC 200V DC

20M

2M 200K

OHMS

200

20K

To Measure Engine RPM (TACH) (see Fig. 11):

1. Insert BLACK test lead into the COM test lead jack.

2. Insert RED test lead into the test lead jack.

3. Connect RED test lead to RPM (TACH) signal wire.

 If vehicle is DIS (Distributorless Ignition

System), then connect RED test lead to the RPM (TACH) signal wire going from the DIS module to the vehicle engine computer. (refer to vehicle service manual for location of this wire)

 For all vehicles with distributors, connect

RED test lead to negative side of primary ignition coil. (refer to vehicle service manual for location of ignition coil)

4. Connect BLACK test lead to a good vehicle ground.

5. Turn multimeter rotary switch to correct RPM X 10 CYLINDER selection.

6. Measure engine RPM while engine is cranking or running.

7. View reading on display.

R X

CYL

DWELL

Fig. 11

CYL

Red

Black

Ground

Typical Ignition

Coil

Measuring Dwell

Dwell measuring was extremely important on breaker point ignition systems of the past. It referred to the length of time, in degrees, that the breaker points remained closed, while the camshaft was rotating. Todays vehicles use

electronic ignition and dwell is no longer adjustable. Another application for dwell is in testing the mixture control solenoid on

GM feedback carburetors. To Measure Dwell (see Fig. 12):

20M

200K

OHMS

Fig. 12

CYL

20K

CYL

DWELL

200

COM

750V AC 200V DC

Red

Black

Ground

Typical

Ignition

Coil

1. Insert BLACK test lead into the COM test lead jack.

2. Insert RED test lead into the test lead jack.

3. Connect RED test lead to DWELL signal wire.

 If measuring DWELL on breaker point

ignition systems, connect RED test lead to negative side of primary ignition coil. (refer to vehicle service manual for location of ignition coil)

 If measuring DWELL on GM mixture

control solenoids, connect RED test lead to ground side or computer driven side of solenoid. (refer to vehicle service manual for solenoid location)

 If measuring DWELL on any arbitrary

ON/OFF device, connect RED test lead to side of device that is being switched ON/OFF.

4. Connect BLACK test lead to a good vehicle ground.

5. Turn multimeter rotary switch to correct DWELL CYLINDER position.

6. View reading on display.

Section 2. Automotive Testing

The digital multimeter is a very useful tool for trouble-shooting automotive electrical systems. This section describes how to use the digital multimeter to test the starting and charging 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. 13):

Fig. 13

Red

Fuse

Black

test

200

COM

750V AC 200V DC

CYL

DWELL

CYL

20M

2M 200K

OHMS

20K

1. Insert BLACK test lead into the COM

test lead jack.

2. Insert RED test lead into the

lead jack.

3. Turn multimeter rotary switch to 200Ω

range.

4. Touch RED and BLACK test leads

together and view reading on display.

Display should read typically 0.2Ω to 1.5Ω. If display reading was greater than 1.5Ω, check both ends of test leads for bad connections. If bad connections are found, replace test leads.

5. Connect RED and BLACK test leads to

opposite ends of fuse.

View reading on display:  Fuse is good if display reading is less

than 10Ω.

 Fuse is blown if display reading indicates

an overrange condition. (see Setting the

Range on page 6) 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. 14):

1. Insert BLACK test lead into the COM test lead jack.

2. Insert RED test lead into the test lead jack.

Fig. 14

750

200

20M

2M 200K

20K

OHMS

3. Turn multimeter rotary switch to 200Ω range.

4. Touch RED and BLACK test leads together and view reading on display.

Display should read typically 0.2Ω to 1.5Ω. If display reading was greater than 1.5Ω, check both ends of test leads for bad connections. If bad connections are found, replace test leads.

5. Connect BLACK test lead to one side of switch.

6. Connect RED test lead to other side of switch.

OFF

COM

CYL

DWELL

200

750V AC 200V DC

Red

Typical "Push"

Button Switch

Black

View reading on display:  Switch is closed if display reading is less

than 10Ω.

 Switch is open if display reading

indicates an overrange condition. (see Setting the Range on page 6)

7. Operate switch.

View reading on display:

 Switch is closed if display reading is less

than 10Ω.

 Switch is open if display reading indicates

an overrange condition. (see Setting the Range on page 6)

8. Repeat Step 7 to verify switch operation.

Good Switch: Display reading alternates from a 10Ω or less value to an overrange condition as you operate switch. Bad Switch: Display reading remains unchanged as you operate switch.

Testing Solenoids and Relays

This test checks to see if a solenoid or relay have a broken coil. If the coil tests good, it is still possible that the relay or solenoid are defective. The relay can have contacts that are welded or worn down, and the solenoid may stick when the coil is energized. This test does not check for those potential problems. To test Solenoids and Relays (see Fig. 15):

Fig. 15

Relay or Solenoid

200

COM

750V AC 200V DC

CYL

DWELL

CYL

Red

Black

20M

2M 200K

OHMS

20K

3. Turn multimeter rotary switch to 200Ω

range.

Most solenoids and relay coil resistances are less than 200Ω. If meter overranges, turn multimeter rotary switch to next higher range. (see Setting the Range on page 6)

4. Touch RED and BLACK test leads together and view display.

Display should read typically 0.2Ω to 1.5Ω. If display reading was greater than 1.5Ω, check both ends of test leads for bad connections. If bad connections are found, replace test leads.

5. Connect BLACK test lead to one side of coil.

6. Connect RED test lead to other side of coil.

7. View reading on display.

 Typical solenoid / relay coil resistances

are 200Ω or less.

 Refer to vehicle service manual for your

vehicles resistance range.

8. Test Results

Good Solenoid / Relay Coil: Display in Step 7 is within manufacturers specification.

Bad Solenoid / Relay Coil:

 Display in Step 7 is not within

manufacturers specifications.

 Display reads overrange on every ohms

range indicating an open circuit. NOTE: Some relays and solenoids have a diode placed across the coil. To test this diode see Testing Diodes on page 9.

1. Insert BLACK test lead into the COM test lead jack.

2. Insert RED test lead into the

lead jack.

test

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.

Fig. 16

OFF

750

200

20M

2M 200K

20K

OHMS

200

COM

Test Procedure (see Fig. 16):

1. Turn Ignition Key OFF.

2. Turn ON headlights for 10 seconds to dissipate battery surface charge.

3. Insert BLACK test lead into the COM test lead jack.

CYL

750V AC 200V DC

CYL

DWELL

Red

Black

4. Insert RED test lead into the lead jack.

5. Disconnect positive (+) battery cable.

6. Connect RED test lead to positive (+) 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 chart below.

Voltage Percent 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 more starting/charging system tests.

test

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.

Fig. 17

OFF

750

200

20M

200K

20K

OHMS

200

COM

Test Procedure (see Fig. 17):

1. Disable ignition system so vehicle 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 the COM test lead jack.

3. Insert RED test lead into the test lead jack.

CYL

750V AC 200V DC

CYL

DWELL

Red

Black

4. Connect RED test lead to positive (+) 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 correspond to chart, then it is possible that the battery, battery cables, starting 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 motor resulting in low battery load voltage and a slow cranking engine at starting. Test Procedure (see Fig. 18):

1. Disable ignition system so vehicle 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 the COM test lead jack.

3. Insert RED test lead into the test lead jack.

4. Connect test leads.

Refer to Typical Cranking Voltage Loss Circuit (Fig. 18).  Connect RED and BLACK test leads

alternately between 1 & 2, 2 & 3, 4 & 5, 5 & 6, 6 & 7, 7 & 8, 8 & 9, and 8 & 10.

5. Turn multimeter rotary switch to 200mV DC range.

If multimeter overranges, turn multimeter rotary switch to the 2V DC range. (See Setting the Range on page 6)

6. Crank engine until steady reading is on display.

 Record results at each point as

displayed on multimeter.

 Repeat Step 4 & 5 until all points are

checked.

7. Test Results 

Estimated Voltage Drop of Starter Circuit Components

Component Voltage

Switches 300mV Wire or Cable 200mV Ground 100mV Battery Cable Connectors 50mV Connections 0.0 V

 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.

Fig. 18 Typical Cranking

Voltage Loss Circuit

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.

Starter

Solenoid

6 8

7 9

Red

Black

Charging System Voltage Test

This test checks the charging system to see if it charges the battery and provides power to the rest of the vehicles electrical systems (lights, fan, radio etc).

Fig. 19

OFF

750

200

20M

2M 200K

20K

OHMS

200

COM

Test Procedure (see Fig. 19):

1. Insert BLACK test lead into the COM test lead jack.

2. Insert RED test lead into the lead jack.

3. Connect RED test lead to positive (+) terminal of battery.

4. Connect BLACK test lead to negative (-) terminal of battery.

5. Turn multimeter rotary switch to 20V DC range.

6. Start engine - Let idle.

CYL

750V AC 200V DC

CYL

DWELL

Red

Black

test

7. Turn off all accessories and view reading on display.

 Charging system is normal if display

reads 13.2 to 15.2 volts.

 If display voltage is not between 13.2 to

15.2 volts, then proceed to Step 13.

8. Open throttle and Hold engine speed (RPM) between 1800 and 2800 RPMs.

Hold this speed through Step 11 - Have an assistance help hold speed.

9. View reading on display.

Voltage reading should not change from Step 7 by more than 0.5V.

10.Load the electrical system by turning on the lights, windshield wipers, and setting the blower fan on high.

11.View reading on display.

Voltage should not drop down below about 13.0V.

12.Shut off all accessories, return 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 normal.

 If any voltage readings in Steps 7, 9, and

11 were different then shown here or in vehicle service manual, then check for a loose alternator belt, defective regulator or alternator, poor connections, or open alternator field current.

 Refer to vehicle service manual for

further diagnosis.

Ignition System Testing

The ignition system is responsible for providing 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, hall effect switches/sensors, reluctance pickup coil sensors, and the switching action of the primary ignition coil.

Ignition Coil Testing

This test measures the resistance of the primary and secondary of an ignition coil. This test can be used for distributorless ignition systems (DIS) provided the primary and secondary ignition coil terminals are easily accessible. Test Procedure:

1. If engine is HOT let it COOL down before proceeding.

2. Disconnect ignition coil from ignition system.

3. Insert BLACK test lead into the COM test lead jack. (See Fig. 20.)

Fig. 20

20M

2M 200K

OHMS

750

200

20K

COM

CYL

DWELL

200

750V AC 200V DC

Secondary

Coil

Red

Typical Cylindrical

Ignition Coil

Black

6. Connect test leads.

 Connect RED test lead to primary

ignition coil positive (+) terminal.

 Connect BLACK test lead to primary

ignition coil negative (-) terminal.

 Refer to vehicle service manual for

location of primary ignition coil terminals.

7. View reading on display.

Subtract test lead resistance found in Step 5 from above reading.

8. If vehicle is DIS, repeat Steps 6 and 7 for remaining ignition coils.

9. Test Results - Primary Coil

 Typical resistance range of

primary ignition coils is 0.3 -

2.0Ω.

 Refer to vehicle service manual

for your vehicle's resistance range.

10.Turn multimeter rotary switch

to 200KΩ range (see Fig. 21).

Primary

Coil

4. Insert RED test lead into the test lead jack.

5. Turn multimeter rotary switch

to 200Ω range.

Touch RED and BLACK test leads together and view reading on display.  Display should read typically

0.2Ω to 1.5Ω.

 If display reading was greater

than 1.5Ω, check both ends of test leads for bad connections. If bad connections are found, replace test leads.

Fig. 21

20M

2M 200K

OHMS

200

750

CYL

20K

CYL

DWELL

200

COM

750V AC 200V DC

Secondary

Coil

Red

Typical Cylindrical

Ignition Coil

Black

Primary

Coil

11.Move RED test lead to secondary ignition coil terminal.

 Refer to vehicle service manual for

location of secondary ignition coil terminal.

 Verify BLACK test lead is connected to

primary ignition coil negative (-) terminal.

12.View reading on display.

13.If vehicle is DIS, repeat Steps 11 and 12 for remaining ignition coils.

14.Test Results - Secondary Coil

 Typical resistance range of secondary

ignition coils is 6.0 - 30.0KΩ.

 Refer to vehicle service manual for your

vehicles resistance range.

15.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 resistance of the coil could change with temperature. This will also help in diagnosing intermittent ignition system problems.

16.Test Results - Overall

Good Ignition Coil: Resistance readings in Steps 9, 14 and 15 were within manufacturers specification. Bad Ignition Coil: Resistance readings in Steps 9, 14 and 15 are not within manufacturers specification.

Ignition System Wires

This test measures the resistance of spark plug and coil tower wires while they are being flexed. This test can be used for distributorless ignition systems (DIS) provided the system does not mount the ignition coil directly on the spark plug. Test Procedure:

1. Remove ignition system wires one at a

time from engine.

 Always grasp ignition system wires on

the boot when removing.

 Twist the boots about a half turn while

pulling gently to remove them.

 Refer to vehicle service manual for

ignition wire removal procedure.

 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. Damage may result if other means of removal are attempted. Refer to vehicle service manual for procedure. NOTE: Some spark plug wires have sheet metal jackets with the following symbol: . This type of plug wire contains an air gap resistor and can only be checked with an oscilloscope.

2. Insert BLACK test lead into the COM

test lead jack. (See Fig. 22.)

Fig. 22

750

200

20M

2M 200K

20K

OHMS

COM

3. Insert RED test lead into the

CYL

DWELL

200

750V AC 200V DC

Spark Plug Wire

Red

Black

test

lead jack.

4. Connect RED test lead to one end of ignition wire and BLACK test lead to other end.

5. Turn multimeter rotary switch to 200KΩ range.

6. View reading on display while flexing ignition wire and boot in several places.

 Typical resistance range is 3KΩ to 50KΩ

or approximately 10KΩ per foot of wire.

 Refer to vehicle service manual for your

vehicles resistance range.

 As you flex ignition wire, the display

should remain steady.

7. Test Results

Good Ignition Wire: Display reading is within manufacturers specification and remains steady while wire is flexed. Bad Ignition Wire: Display reading erratically changes as ignition wire is flexed or display reading is not within manufacturers specification.

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