C0394

DTC C0394

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.

DTC Descriptor
DTC C0394 00
- Rear Axle Coupling Temperature Sensor Circuit

Diagnostic Fault Information





Circuit/System Description

The rear axle differential temperature sensor is a two wire sensor that is a variable resistor type. It is used by the instrument panel cluster (IPC) to monitor the temperature of the rear axle. The IPC provides a 5 volt reference and receives a signal voltage from the sensor which is mounted on the rear differential housing.

Conditions for Running the DTC

Ignition ON

Conditions for Setting the DTC

The IPC detects signal voltage less than 0.1 V or greater than 5 V for 60 seconds.

Action Taken When the DTC Sets

The SERVICE DIFFERENTIAL SENSOR message is displayed on the IPC.

Conditions for Clearing the DTC

* The DTC will become history if the IPC no longer detects a failure.
* The history DTC will clear after 100 fault-free ignition cycles.

Reference Information
Schematic Reference

Rear Axle Schematics (Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Rear Drive Axle Description and Operation (Description and Operation)
Electrical Information Reference

* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)

Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information

Circuit/System Verification

Ignition ON, observe the IPC Rear Differential Temp Sensor parameter. The value should be.1-4.9 volts and should change with rear differential temperature.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the rear differential temperature sensor.
2. Ignition ON, test for 4.8-5.2 V between the 5 V reference circuit terminal 1 and ground.

• If less than the specified range, test the reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the IPC.
• If greater than the specified range, test the reference circuit for a short to voltage. If the circuit tests normal, replace the IPC.

3. With a scan tool, verify the IPC Rear Differential Temp Sensor parameter is less than 0.1 V.

• If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the IPC.

4. Install a 3 A fused jumper wire between the signal circuit terminal 2 and the reference circuit terminal 1. With a scan tool, verify the IPC Rear Differential Temp Sensor parameter is greater than 4.8 V.

• If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the IPC.

5. If all circuits test normal, test or replace the rear differential temperature sensor.

Component Testing

1. Ignition OFF, disconnect the harness connector at the rear differential temperature sensor.
2. Test for 25-10K ohm between the sensor signal terminal 2 and the low reference circuit terminal 1.

• If not within the specified range, replace the rear differential temperature sensor.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Differential Temperature Sensor Replacement (Differential Temperature Sensor Replacement)
* Control Module References (Programming and Relearning) for IPC replacement, setup, and programming.