CAB FLOOR, UPPER 0993291 - Caterpillar

You should make sure that diagnostic code CID 0168 FMI 01 is on hold and the fault present indicator is showing "SERV CODE" on the Caterpillar Monitoring System.
Check the battery voltage.
Start the engine and operate the engine at high idle for several minutes.
Measure the battery voltage at the battery posts.Expected Result The battery voltage is 24.8 DCV or above 24.8 DCV.Results
OK - Battery voltage is at 24.8 DCV or above 24.8 DCV. The battery voltage is correct. Proceed to Step 2.
NOT OK - Battery voltage is below 24.8 DCV. The charging system is not operating correctly. Check the charging system. Refer to Systems Operation/Testing and Adjusting, "Starting And Charging System" for the machine that is being serviced. STOP.
Check the system voltage at the power train ECM.
The engine must be running at high idle.
Use the 7X-1710 Multimeter Probe test leads in order to measure the voltage at connector J1 of the power train Electronic Control Module (ECM). Measure the system voltage between wires 126-PK and 229-BK at contacts J1-1, J1-6 and J1-2, J1-5 of the harness connector.Expected Result The voltage is below 24.8 DCV.Results
YES - Voltage is below 24.8 DCV. The harness is not correct. Repair the harness or replace the harness. STOP.
NO - Voltage is at or above 24.8 DCV. The system voltage is correct. Proceed to Step 3.
Check if the fault is still present.
Stop the engine. Turn the battery disconnect switch to the OFF position.
Disconnect the harness connector J1 from the power train ECM and inspect contacts 1, 6 and 2, 5. Reconnect the harness connector to the power train ECM.
Turn the battery disconnect switch to the ON position. Start the machine.
Check that diagnostic code CID 0168 FMI 01 is still present on the display. The fault is present. It is unlikely that the power train ECM is the problem. Perform the previous steps again. If the cause of the fault is not found replace the power train ECM. Refer to Testing and Adjusting, "Electronic Control Module (Power Train) - Replace" for information on replacing the power train ECM. STOP.