C0237

Circuit Description
The EBCM receives the rear wheel speed signal from the VCM (4.3L only) or the PCM. When the vehicle is moving, the EBCM compares the rear wheel speed signal to both of the front wheel speed sensor signals.

Conditions for Running the DTC
^ The ignition is ON.
^ All of the wheel speed sensor signals are above 32 km/h (20 mph) when the brake is applied or 19 km/h (12 mph) when the brake is released.

Conditions for Setting the DTC
Either of the following conditions will set DTC C0237:
^ A sudden loss of the rear wheel speed signal is detected for 15 milliseconds.
^ A sudden increase is detected in the rear wheel speed signal for 105 milliseconds.

Action Taken When the DTC Sets
^ The ABS, BRAKE and TRACTION OFF (if equipped with Traction Control) indicators are commanded on.
^ The ABS, DRP and Traction Control (if equipped) are disabled for as long as the malfunction is present. If the malfunction occurs 3 or more separate times, the ABS and Traction Control are disabled for the remainder of the ignition cycle.

Conditions for Clearing the DTC
^ The condition(s) responsible for setting the DTC are no longer present.
^ A scan tool is used in order to clear the DTC.

Important: After the DTC is cleared and the ignition is ON, the ABS indicator may remain on until the EBCM completes a power-up self-test. This test concludes when the vehicle reaches a speed of greater than 13 km/h (8 mph) and the wheel speeds are verified by the EBCM.

Diagnostic Aids
Operating the vehicle on extremely rough terrain can set DTC C0237 even if the system is not malfunctioning.
Thoroughly inspect connections or circuitry that may cause an intermittent malfunction. Refer to Testing for Intermittent and Poor Connections, Wiring Repairs and Connector Repairs under Diagrams, Diagnostic Aids.

Test Description
The number below refers to the step number on the diagnostic table:
4. This step tests for an erratic rear wheel speed signal from the VCM/PCM.