PLUG-BREAKOFF 9T3941 - Caterpillar

Which Generate This Code:This diagnostic code is associated with a low system voltage. This diagnostic code is recorded when the system voltage is below 9 VDC. On a machine with a 24 volt system, this diagnostic may not be recorded, even if a low voltage condition is present.The possible causes of this diagnostic code are listed below:
A charging system component has failed.
The wiring in the machine harness has failed.
The ECM has failed. This is unlikely.Test Step 1. CHECK THE BATTERY VOLTAGE.
Start the engine and run the engine at high idle for several minutes. Make sure that no battery charger is connected to the engine.
Measure the battery voltage at the battery posts.Expected Result:The battery voltage should be greater than 9 VDC for a 12 volt system, and the battery voltage should be greater than 21.3 VDC for a 24 volt system.Results:
OK - The battery voltage is good. Proceed to Test Step 2.
NOT OK - The battery voltage is too low.Repair: The charging system is not correct. Check the charging system. See Special Instruction, REHS0354, "Charging System Troubleshooting". Stop.Test Step 2. CHECK THE SYSTEM VOLTAGE AT THE ECM.
The engine must still be running at high idle.
DO NOT DISCONNECT the machine harness from the ECM. At the connector of the ECM, prepare to make a voltage measurement by using the 7X-1710 Multimeter Probe .
At the machine harness for the ECM, insert the probe into the back of connector. Measure the voltage (VDC) between pin 1 and pin 3.Expected Result:The battery voltage should be greater than 9 VDC for a 12 volt system, and the battery voltage should be greater than 21.3 VDC for a 24 volt system.Results:
OK - The battery voltage is correct. Proceed to Test Step 3.
NOT OK - The battery voltage is too low.Repair: The machine harness is not correct. Repair the machine harness or replace the machine harness. Stop.Test Step 3. CHECK IF THE DIAGNOSTIC CODE IS STILL ACTIVE.
Remove the connector from the ECM. Inspect the contacts and clean the contacts of the harness connectors.
Reconnect all harness connectors.
Turn the key start switch to the ON position.
Clear all inactive diagnostic codes.
Operate the machine.
Determine if CID 0168 FMI 01 is present.Expected Result:CID 0168 FMI 01 is present.Results:
YES - CID 0168 FMI 01 is present.Repair: The problem has not been corrected. It is unlikely that the ECM has failed. Perform the previous Test 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 - CID 0168 FMI 01 is not present.Repair: The diagnostic code is NOT present. The problem does not exist at this time. The initial problem 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.