2010 Cadillac CTS Sedan AWD V6-3.6L Page 653
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 module detects an internal motor malfunction.
Action Taken When the DTC Sets
* The electric parking brake is disabled.
* A DIC message and/or a warning indicator may be displayed.
Conditions for Clearing the DTC
* The electric parking brake 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 (See: Brakes and Traction Control/Parking Brake System/Diagrams/Electrical Diagrams)
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views)
Description and Operation
Electronic Parking Brake Control Module Description (See: Brakes and Traction Control/Parking Brake System/Parking Brake Control
Module/Description and Operation)
Electrical Information Reference
* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/Circuit Testing/Circuit Testing)
* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/Connector Repairs/Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection/Component Tests and General Diagnostics/Circuit
Testing/Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/Wiring Repairs/Wiring Repairs)
Scan Tool Reference
Control Module References (See: Testing and Inspection/Programming and Relearning) for scan tool information
Circuit/System Verification
With a scan tool, perform the Parking Brake Actuator DTC Reset procedure. Verify DTC C028A is not set.
