KIT - 2637658 - Caterpillar

This diagnostic code is recorded when the ECM reads the system voltage as being below 23.0 DCV.The possible causes of this diagnostic code are listed:
A charging system component is faulty.
The machine harness is faulty.
The ECM has failed. This is unlikely. System Response:When this diagnostic code occurs, a warning (Category 3) is shown on the monitor. The transmission will shift into NEUTRAL if system voltage drops below approximately 18 DCV. Normal operation will resume after the problem has been corrected and after the speed/direction control lever has been returned to PARK. The normal operation resumes when the voltage recovers above 23 DCV.Test 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 23.0 DCV.Results:
OK - The battery voltage is greater than 23.0 DCV. The battery voltage is correct. Proceed to test step 2.
NOT OK - The battery voltage is NOT greater than 23.0 DCV.Repair: Check the charging system. See Special Instruction, REHS0354, "Charging System Troubleshooting" for more information.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 (DCV) between contacts D-1 (wire 164-WH(White)) and contact D-2 (wire 202-BK(Black)). Expected Result:The voltage measurement is greater than 23.0 DCV.Results:
OK - The voltage is greater than 23.0 DCV. The battery voltage is correct. Proceed to test step 3.
NOT OK - 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 connector B and connector D from the ECM. Inspect the contacts of the harness connectors and clean the contacts.
Reconnect all harness connectors.
Turn the key start switch and the disconnect switch to the ON position.
Enter the service mode of the Caterpillar Monitoring System and clear all inactive diagnostic codes.
Operate the machine.
View the status of CID 0168 FMI 04. Expected Result:The diagnostic code is NO longer active.Results:
YES - The diagnostic code is NO longer active. The diagnostic code does not exist at this time. The initial diagnostic code was probably caused by a poor electrical connection or a short at one of the harness connectors that was disconnected and reconnected.STOP
NO - The diagnostic code has NOT been corrected. Repair: Resume normal machine operation. It is unlikely that the ECM is faulty. Exit this procedure and perform this procedure again. If the cause of the diagnostic code is not found, replace the ECM. See Testing and Adjusting, "Electronic Control Module (ECM) - Replace".STOP