GM Service Manual Online
For 1990-2009 cars only

Diagnostic Instructions

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

DTC Descriptor

DTC C0550 00: 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 switch is in the ON position.

Conditions for Setting the DTC

An internal EBCM malfunction exists.

Action Taken When the DTC Sets

One or more of the following actions may occur:

    • The antilock brake system (ABS) dynamic rear proportion (DRP) are disabled.
    • ETS is degraded.
    • The ABS/ESC/ETS indicators turn ON.
    • The red BRAKE Warning indicator turns ON.

Conditions for Clearing the DTC

The EBCM automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.

Circuit/System Verification

Verify that the DTC will clear with a scan tool and does not reset.

If the DTC will not clear with a scan tool, replace the EBCM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for EBCM replacement, setup, and programming