C0538

DTC C0538
Circuit Description
The rear wheel steering module provides the current that activates the rear wheel steering motor actuator control circuits. Phase A , phase B, and phase C are the input circuits to the steering gear motor assembly. In its active state, the output current is pulse width modulated with up to 85 amps at 12 volts, with a normal range of 20-50 amps. When the rear wheel steering control module does not see the rear wheel steering gear motor respond to the current inputs properly the rear wheel steering control module will set a DTC C0538.

DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC C0538 Rear Steering Motor Circuit

Conditions for Running the DTC
The fault is detected when the engine is ON.

Conditions for Setting the DTC
^ Rear steering motor circuits short to positive battery voltage
^ Rear steering motor circuits short to ground
^ Rear steering motor circuits open

Action Taken When the DTC Sets
^ The Service 4 Wheel Steer indicator in Instrument Panel Cluster (IPC) will be displayed.
^ The code is displayed on the scan tool as DTC C0538.
^ The output command to the motor is zeroed. The motor drive circuits are disabled using commands to open the power relay and to close the motor shorting relay.
^ Rear wheels returned to the centered position.

Conditions for Clearing the DTC
^ The conditions for the DTC are not currently present.
^ The rear wheel steering control module receives a clear code command from the scan tool.
^ The history DTC clears after 100 malfunction free ignition cycles.

Diagnostic Aids
^ Inspect for poor connections at the harness connector of the rear wheel steering control module and inspect the wiring harness. Refer to Testing for Intermittent Conditions and Poor Connections , and to Connector Repairs.
^ Observe the rear wheel steering mode select switch. If all of the mode indicator LEDs are illuminated the rear wheel steering control module has lost its memory settings and the scan tool must be used to re-calibrate the rear wheel steering alignment data in the rear wheel steering control module. Refer to Measuring Wheel Alignment (w/Rear Wheel Steering) Measuring Wheel Alignment (w/o Rear Wheel Steering) in Wheel Alignments.

Test Description





The numbers below refer to the step numbers on the diagnostic table.
2. This step will help the technician determine if there is an intermittent connection at the harness connector of the rear wheel steering motor.