For 1990-2009 cars

### DTC Descriptor

DTC C0550: Electronic Control Unit (ECU) Performance

### Diagnostic Fault Information

Important: Always perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

### 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.

• | The ABS/TCS/ESC indicators turn ON.

• | The red BRAKE Warning indicator turns ON.

### Conditions for Clearing the DTC

• | The condition for the DTC is no longer present and the DTC is cleared with a scan tool.

• | 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

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

Scan Tool Data List for EBCM

### Circuit/System Verification

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

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

⇒ | Replace the EBCM.