Actron CP7677 Operations Instructions download pdf (Page 17)

17

If multimeter overranges, turn multim-

eter 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 0.0V

• Compare voltage readings in Step

6 with above chart.

• If any voltages read high, inspect com-

ponent and connection for defects.

• If defects are found, service as

necessary.

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 sys-

tem. 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. 22):

1. Disable ignition system so vehicle

won’t start.

Disconnect the primary of the igni-

tion coil or the distributor pick-up coil

or the cam/crank sensor to disable

the ignition system. Refer to vehicle

service manual for disabling proce-

dure.

2. Insert BLACK test lead into COM

test lead jack.

3. Insert RED test lead into

test lead jack.

4. Connect test leads.

Refer to Typical Cranking Voltage

Loss Circuit (Fig. 22).

•

Connect RED and BLACK test leads

alternately between 1 & 2, 2 & 3, 4 &

5, 5 & 6, 6 & 7, 7 & 9, 8 & 9, and 8 &

10.

5. Turn multimeter rotary switch to

200mV DC range.

1

10

2

4

5

6 8

7

7

9

8

9

6

2

4

5

3

3

Red Black

Fig. 22 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.

Starter

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