Voltage drops, Fig. 20 typical cranking voltage loss circuit – Actron AutoAnalyzer CP7665 User Manual

Page 18

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5. Turn multimeter rotary switch

to 200mV DC range.

If multimeter overranges, turn mul-
timeter rotary switch to the
2000mV 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

Test Procedure (see Fig. 20):

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

test lead jack.

4. Connect test leads.

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

• 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.

Red

Black

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.

Starter

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.

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