C028A

DTC C028A

Diagnostic Instructions

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

DTC Descriptors
DTC C028A 01
- Park Brake Motor Circuit Short to Battery

DTC C028A 02
- Park Brake Motor Circuit Short to Ground

DTC C028A 04
- Park Brake Motor Circuit Open Circuit

DTC C028A 08
- Park Brake Motor Circuit Performance-Signal Invalid

DTC C028A 28
- Park Brake Motor Circuit Performance-Incorrect Frequency

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. The electric parking brake module will also diagnose the internal park brake motor circuit to verify it is functioning properly. The park brake motor circuit is used to command motor operation, apply and release tension on the parking brake cable, which will apply and release the parking brake.

The electric park brake will self diagnose the internal Park Brake Motor Circuit. This circuit is used to drive the motor, which pulls on the electric park brake cable, ultimately applying and releasing the park brake.

Conditions for Running the DTC

* Ignition OFF, ACCESSORY, or RUN mode.
* Battery voltage is between 9 -16V

Conditions for Setting the DTC

The electric parking brake control module detects an internal motor malfunction.

Action Taken When the DTC Sets

* The electric parking brake is disabled.
* 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.

Reference Information
Schematic Reference

Park Brake System Schematics ([1][2]Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Electronic Parking Brake Control Module Description (Description and Operation)
Electrical Information Reference

* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing For Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)

Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information

Circuit/System Verification

With a scan tool, perform the Parking Brake Control Module DTC Reset procedure. Verify DTC C028A is not set.

If DTC is set, replace the K83 Parking Brake Control Module.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

Control Module References (Programming and Relearning) for electric parking brake control module replacement, setup, and programming.