Test Step 4. Check the Batteries

291

TM 9-2320-312-24-2

Troubleshooting Section

g00640981

Illustration 120

ECM Breakout T-connector

Battery Voltage is out of range Proceed to Test

C. Measure the voltage from vehicle harness

connector P1 terminal 53 (unswitched +battery)

Step 4.

and terminal 67 (-battery).

Intermittent Or No Voltage Proceed to Test Step

Refer to Illustration 120 for the ECM breakout

T-connector.

Key Switch Voltage Out Of Range

Perform Steps D, E, and F if the following

Repair: Trace the wiring for the ignition key switch

diagnostic code is active or logged:

from the ECM through the key switch circuit to

43-02 Ignition Key Switch Fault (71)

the batteries. Find the problem and repair the

problem. Check the circuit protection for the

circuit and the wiring. Refer to the vehicle service

D. Disconnect vehicle harness connector P1 from

manual for instructions on troubleshooting the

ECM connector J1 and insert a breakout T.

circuit for the ignition key switch.

E. Turn the ignition key switch to the ON position.

Verify that the repairs eliminate the problem.

F. Measure the voltage between vehicle harness

connector P1 terminal 70 (Ignition Key Switch)

STOP.

and terminal 65 (-battery).

Test Step 4. Check the Batteries.

Refer to Illustration 120 for the ECM breakout

T-connector.

A. Measure no-load battery voltage at the battery

posts.

Expected Result:

B. Load test the batteries. Use the 4C-4911

For 12 Volt Systems, the measured voltage is a

Battery Load Tester. Refer to Special Instruction,

constant 11.0 to 13.5 VDC with no suspected

SEHS9249, "Use of 4C-4911 Battery Load Tester

intermittent problems at this time.

for 6, 8 and 12 Volt Lead Acid Batteries" and

Special Instruction, SEHS7633, "Battery Test

For 24 Volt Systems, the measured voltage is a

Procedure".

constant 22.0 to 27.0 VDC with no suspected

intermittent problems at this time.

Expected Result:

The batteries pass the load test. For 12 Volt

Results:

Systems, the measured voltage is at least 11.0. For

OK The ECM is receiving the correct voltage.

24 Volt Systems, the measured voltage is at least

22.0.

Repair: If an intermittent condition is suspected,

refer to Troubleshooting, "Electrical Connectors

Results:

- Inspect".

YES

STOP.