GM Service Manual Online
For 1990-2009 cars only

DTC Descriptor

DTC C0550 00: Electronic Control Unit (ECU) Performance

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Electronic Control Unit (ECU) Performance

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C0550 00

Circuit/System Description

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

Conditions for Running the MIL/DTC

The ignition switch is in the ON position.

Conditions for Setting the MIL/DTC

An internal EBCM malfunction exists.

Action Taken When the MIL/DTC Sets

One or more of the following actions may occur:

    • The antilock brake system (ABS) and vehicle stability enhancement system (VSES) are disabled.
    • TCS is degraded.
    • The ABS/TCS indicators turn ON.
    • The red BRAKE Warning indicator turns ON.

Conditions for Clearing the MIL/DTC

    •  The ABS Indicator may remain illuminated after the DTCs are cleared, until the vehicle is driven at speeds greater than 13 km/h (8 mph) and the self test is completed.
    • The condition for the DTC is no longer present.
    • The EBCM automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.

Diagnostic Aids

Verify that the EBCM power and ground circuits are good if the DTC C0550 is stored in history.

Reference Information

Schematic Reference

Antilock Brake System Schematics

Connector End View Reference

Antilock Brake System Connector End Views

Description and Operation

ABS Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

Control Module References for EBCM

Circuit/System Verification

DTC C0550 will set as result of internal (EBCM) circuit failure.

Replace the EBCM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for EBCM replacement, setup, and programming