GM Service Manual Online
For 1990-2009 cars only

Diagnostic Instructions

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

DTC Descriptor

DTC C0550: Electronic Control Unit (ECU) Performance

Circuit/System Description

The electronic brake control module (EBCM) detects an internal malfunction.

Conditions for Running the DTC

The ignition is ON.

Conditions for Setting the DTC

The EBCM detects an internal malfunction.

Action Taken When the DTC Sets

One or more of the following actions may occur:

    â€¢ The EBCM disables the ABS/dynamic rear proportioning (DRP)/traction control system (TCS)/vehicle stability enhancement system (VSES).
    â€¢ The ABS indicator illuminates.
    â€¢ The brake warning indicator illuminates.
    â€¢ The message center displays the service stability system message.
    â€¢ The traction off indicator illuminates.

Conditions for Clearing the DTC

    â€¢ The condition for the DTC is no longer present.
    â€¢ The EBCM automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.

Reference Information

Schematic Reference

Antilock Brake System Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

ABS Description and Operation

Electrical Information Reference

    â€¢  Circuit Testing
    â€¢  Connector Repairs
    â€¢  Testing for Intermittent Conditions and Poor Connections
    â€¢  Wiring Repairs

Scan Tool Reference

Control Module References for Scan Tool Information

Circuit/System Verification

Verify that DTC C0550 is not set.

⇒If the DTC is set, clear the DTC with a scan tool, and operate the vehicle within the conditions for setting the DTC. If the DTC reset, replace the EBCM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for EBCM replacement, setup, and programming