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 provide an overview of each diagnostic category.

### DTC Descriptors

DTC C056E 41: Electronic Control Unit Software Not Programmed
DTC C056E 42: Electronic Control Unit Software Calibration Not Programmed
DTC C056E 5A: Electronic Control Unit Software Not Plausible

### Circuit/System Description

The electric parking brake control module has an internal motor, apply actuator, release actuator, and temperature sensor. The electric parking brake control module also contains the logic for applying and releasing the parking brake when commanded by the electric parking brake switch. When the electric parking brake control module receives a signal from the switch the internal circuit board temperature is checked to verify it is within operating range before the control module performs the requested operation.

### Conditions for Running the DTC

Ignition OFF, ACCESSORY, or RUN mode.

### Conditions for Setting the DTC

The electric parking brake control module has detected an internal software malfunction.

### Actions Taken When DTC Sets

#### C056E 41, C056E 5A

• | The electric parking brake is disabled.

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

#### C056E 42

• | The electric parking brake functionality is degraded.

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

### Conditions for Clearing the DTC

• | The electric parking brake control module clears the history DTC when a current DTC is not detected in 40 ignition cycles.

• | The condition for the DTC is no longer present.

• | The latest software and calibrations are programmed into the electric parking brake control module.

### Reference Information

#### Schematic Reference

Park Brake System Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Electronic Parking Brake Control Module Description

#### 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 C056E is not set.

⇒ | If the DTC is set, perform the Electronic Parking Brake Control Module Programming and Setup. If the DTC resets, replace the K83 Electric Parking Brake Control Module.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for electric parking brake control module replacement, setup, and programming