C0055

Antilock Brake System

Diagnostic Information and Procedures

DTC C0055

Circuit Description

The powertrain control module (PCM) converts the signal from the vehicle speed sensor (VSS) to a 128k pulses/mile signal. The electronic brake control module (EBCM) uses the vehicle speed signal from the PCM to calculate the rear wheel speed.

Conditions for Running the DTC

The ignition is ON.
The vehicle speed is greater than 13 km/h (8 mph).

Conditions for Setting the DTC

The EBCM detects an open or shorted vehicle speed signal circuit for 500 milliseconds.
The EBCM detects the absence of the vehicle speed signal for 5 seconds. If more than one absent wheel speed sensor signal is detected, the condition must be present for 120 seconds to set DTCs.
The EBCM detects an erratic vehicle speed signal for 200 milliseconds.

Action Taken When the DTC Sets

The EBCM disables the ABS/DRP.
The ABS indicator turns ON.
The brake warning indicator turns ON.
The actions above are maintained during subsequent ignition cycles until the EBCM completes a power up self-test. This test concludes when the vehicle achieves a speed greater than 13 km/h (8 mph) and the wheel speeds are verified by the EBCM.

Conditions for Clearing the DTC

The Conditions for Setting the DTC are no longer present and you use the scan tool Clear DTC's function.

Diagnostic Aids

Thoroughly inspect connections or circuitry that may cause an intermittent malfunction. Refer to Testing for Intermittent and Poor Connections, Connector Repairs, Testing for Electrical Intermittents and to Wiring Repairs in Wiring Systems.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

3. This step tests for a voltage signal from the PCM.
4. This step tests for a missing or erratic vehicle speed signal from the PCM. An assistant may be required to perform this test.

DTC C0055 Steps 1 - 3:

DTC C0055 (cont'd) Steps 4 - 10: