rear drive axle oil temperature sensor circuit fault code 7703

The fault code 7703 is related to the rear drive axle oil temperature sensor circuit in PACCAR trucks. This code indicates an open circuit in the rear drive axle oil temperature sensor. Here are some possible causes:

1. Broken wire

2. Corroded or disconnected connector

3. Sensor failure

here are some steps to troubleshoot the rear drive axle oil temperature sensor circuit fault code 7703:

1. Check the Wiring: Inspect the wiring harness for any signs of damage, corrosion, or disconnection. Pay special attention to the wires connected to the sensor2.

2. Inspect the Connector: Ensure that the connector at the sensor is securely attached and free from corrosion.

3. Test the Sensor: Use a multimeter to check the continuity of the sensor. If the sensor is faulty, it may need to be replaced1.

4. Check the ECM/CECU: Ensure that the Electronic Control Module (ECM) or Control Electronic Control Unit (CECU) is functioning correctly. Sometimes, the issue might be with the ECM/CECU rather than the sensor itself1.

5. Simulate the Sensor: If you have access to diagnostic tools like the PACCAR ESA (Electronic Service Analyst), you can simulate the sensor to see if the gauge responds correctly.