For 1990-2009 cars

### 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
DTC C0550 01: Electronic Control Unit (ECU) Performance Short to Battery
DTC C0550 04: Electronic Control Unit (ECU) Performance Open Circuit

### 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 EBCM disables the antilock brake system (ABS).

• | The EBCM disables or degrades the dynamic rear proportining (DRP) function.

• | A DIC message and/or a warning message may be displayed.

### 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

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

Control Module References for Scan Tool Information

### Circuit/System Verification

Verify DTC C0550 is not current.

⇒ | If DTC C0550 is current, replace the EBCM.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.