AIR COMPRESSOR GP 3843659 - Caterpillar

Illustration 6 g01899498
Inverter Cabinet low voltage compartment that contains the motor control ECMs
At the Inverter Cabinet. Remove the compartment cover (3) for the low voltage compartment that contains the motor control ECMs and the interface modules.
At the Motor 1 ECM, disconnect the J1 harness wiring connector from the ECM.
At the Motor 2 ECM, disconnect the J1 harness wiring connector from the ECM.
At the Motor 2 ECM harness connector J1, measure the resistance between the sensor positive (+) contact J1-10 (wire RTDM2-2P-BK(Black)) and a good cabinet ground point. Measure the resistance between the sensor positive (+) contact J1-10 and all of the other circuit contacts that are used in the J1 harness connector.
Measure the resistance between the Motor 2 ECM positive (+) contact J1-10 (wire RTDM2-2P-BK(Black)) and all of the other circuit contacts that are used in the Motor 1 ECM J1 harness connector.
Repeat this resistance measurement between each of the temperature sensor negative circuits, cabinet ground, and all of the other circuits that are used in the J1 connectors for the Motor 1 ECM and the Motor 2 ECM. Expected Result:At the ECM J1 connectors, each of the resistance measurements between the temperature sensor circuits, cabinet ground, and all of the other circuits that are used in both motor control ECM J1 connectors are greater than 4000 ohms.Results:
OK - Each individual resistance measurement is greater than 4000 ohms. The resistance measurements are indicating that the temperature sensor circuits are not shorted to cabinet ground or to any other circuit that is used in the ECM J1 connectors. Proceed to the Test Step 5.
NOT OK - At least one or more of the resistance measurements between the temperature sensor circuits, cabinet ground, or another circuit is much less than 4000 ohms. The low resistance between the circuits is indicating that there is a short circuit between one of the temperature sensor circuits and either frame ground or another circuit.Repair: The motor winding temperature sensor connection diagram at the beginning of this procedure shows all of the circuit connections that are in the Inverter Cabinet. For complete machine harness and connector information in the circuits between the cabinet connectors and the temperature sensor in the rear axle housing, refer to the complete machine electrical system schematic.Check the connectors that are used in the circuits for any contamination, damage, or other conditions that could cause a short circuit.Examine the wiring harness that contains the suspect circuits that are indicating the low resistance measurement. Look for areas where the wire insulation could be worn or damaged causing contact with the Inverter Cabinet frame or the machine frame.Locate and examine all of the circuit connections that are used in the suspected sections of the temperature sensor circuit. Check each wire section between connectors for a short circuit.Repair the machine harness or replace the machine harness. STOPTest Step 5. CHECK THE STATUS OF THE DIAGNOSTIC CODE
Inspect the harness wiring connectors for the ECM and the phase module that are disconnected. Clean the contacts of the