SHAFT-AXLE 3855520 - Caterpillar

diagnostic code is recorded when the ECM reads the system voltage as below 23 DCV. The result of this diagnostic code is:
A category 3 warning is showing on the Computerized Monitoring System. The possible causes of this diagnostic code are:
A charging system component is faulty.
The machine harness wiring is faulty.
The ECM is faulty (unlikely).
Check Battery Voltage.
Start the engine and run at high idle for several minutes.
Measure the battery voltage at the battery posts. Expected Result: The battery voltage is greater than 23 DCV. Results:
YES - Battery voltage is correct. Proceed to next step.
NO - The charging system is not correct. Check and repair the charging system. STOP.
Check System Voltage At ECM.
The engine must be running at high idle.
DO NOT DISCONNECT the machine harness from the ECM. At the ECM harness connector, prepare to make a voltage measurement using the 7X-1710 Multimeter Probe .
At the machine harness for the ECM, measure the voltage (DCV) between contact 1 (+battery, 119-PK) and contact 2 (ground, 200-BK).Expected Result: The voltage is greater than 23 DCV. Results:
YES - Battery voltage is correct. Proceed to next step.
NO - The machine harness is not correct. Repair or replace the machine harness. STOP.
Check If Diagnostic Code Remains.
Clean the contacts of the harness connectors.
Reconnect all harness connections.
Turn the key start switch to the ON position.
Enter service mode of the ECM and clear all inactive diagnostic codes.
Operate the machine.
Check to see if CID 060 FMI F01 service code is present. Expected Result: The CID 060 FMI F01 service code present.Results:
YES - The diagnostic code has not been corrected. It is unlikely that the ECM is faulty. Perform the previous Steps again. If the cause of the diagnostic code is not found, replace the ECM. See Testing And Adjusting, "Electronic Control Module (ECM) - Replace". STOP.
NO - Diagnostic code is NOT present; 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. Resume normal machine operation. STOP.