ENGINE AR 5C8965 - Caterpillar

Illustration 1 g03157636
Schematic of battery voltage connections
This diagnostic code is recorded when the Electronic Control Module (ECM) reads the system voltage that is below 21.3 V.The possible causes of this diagnostic code are listed:
A charging system component has failed
The machine harness has failed
The ECM may have failed, but is unlikelyTest Step 1. CHECK THE BATTERY VOLTAGE
Start the engine and run the engine at high idle for several minutes.
Measure the voltage of the battery at the battery posts. Expected Result:The battery voltage should be greater than 21.3 V.Results:
YES - The battery voltage is greater than 21.3 V. The battery voltage is correct. Proceed to Test Step 2.
NO - The battery voltage is not greater than 21.3 V.Repair: Check the charging system. See Special Instruction, REHS0354.STOPTest Step 2. CHECK THE SYSTEM VOLTAGE AT THE ECM
The engine remains running at high idle.
Do not disconnect the machine harness from the ECM.
Use the 7x-1710 Multimeter Probe to measure the positive voltage between contacts J1-1 (wire 164-WH(White)), J1-31, J1-38, J1-39, J1-47 (wire 101-RD(Red)), and ground contacts J1-13, J1-23, J1-57, J1-70 (wire 202-BK(Black)). Expected Result:The voltage measurement is greater than 21.3 V.Results:
YES - The voltage is greater than 21.3 V. The battery voltage is correct. Proceed to Test Step 3.
NO - The voltage is not correct. The machine harness has failed.Repair: Repair the machine harness or replace the machine harness.STOPTest Step 3. CHECK IF THE DIAGNOSTIC CODE REMAINS
Turn the key start switch and the disconnect switch to the OFF position.
Disconnect the machine harness connectors from the ECM. Inspect the harness and clean the contacts of the harness connectors.
Reconnect all harness connectors.
Turn the disconnect switch and the key start switch to the ON position.
Clear all the active diagnostic codes.
Operate the machine.
View the status of CID 0168 FMI 04. Expected Result:CID 0168 FMI 04 is no longer active.Results:
YES - CID 0168 FMI 04 is no longer active. The diagnostic code does not exist at this time.Repair: The initial diagnostic code was probably caused by:
A poor electrical connection
A short at one of the harness connectors that was disconnected and reconnectedSTOP
NO - CID 0168 FMI 04 is no longer active has not been corrected.Repair: Resume normal machine operation. The ECM is unlikely to have failed. Exit this procedure and perform this procedure again. If the cause of the diagnostic code is not found, replace the ECM. See Troubleshooting, Testing, and Adjusting, "Electronic Control Module (ECM) - Replace".STOP