C0278

DTC C0278

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) provides an overview of each diagnostic category.

DTC Descriptor
DTC C0278 00
- Brake Pedal Position Sensor Not Calibrated

Diagnostic Fault Information





Circuit/System Description

The brake pedal position sensor is used to sense the action of the driver application of the brake pedal. The brake pedal position sensor provides an analog voltage signal that will increase as the brake pedal is applied. The body control module (BCM) provides a low reference signal and a 5 V reference voltage to the brake pedal position sensor. When the variable signal reaches a voltage threshold indicating the brakes have been applied, the BCM will apply voltage to the center high mounted stop lamp (CHMSL) relay coil. When the CHMSL relay receives voltage from the BCM, the relay coil is energized and the CHMSL relay switch contacts close applying battery voltage to the CHMSL, transmission control module (TCM), and engine control module (ECM).

Conditions for Running the DTC

Battery voltage must be between 9-16 V.

Conditions for Setting the DTC

The brake pedal position sensor home position is not learned.

Actions Taken When the DTC Sets

* The Service Vehicle Soon indicator is commanded ON.
* When DTC C0278 is set as current, the vehicle will not start.
* Stop lamps may not activate at the expected brake pedal positions.

Conditions for Clearing the DTC

* A successful brake pedal position sensor calibration has been performed.
* The condition responsible for setting the DTC no longer exists.
* A history DTC will clear once 50 malfunction-free ignition cycles have occurred.

Reference Information
Schematic Reference

Exterior Lights Schematics (Exterior Lights Schematics)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Exterior Lighting Systems Description and Operation (Exterior Lighting Systems 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 Testing

1. Verify that the DTC sets under the Conditions for Running and Setting.
2. Perform the brake pedal position sensor recalibration procedure. Refer to Brake Pedal Position Sensor Calibration (Brake Pedal Position Sensor Calibration).
3. Operate the vehicle within the conditions that the customer experienced and verify the DTC does not reset.

• If the DTC resets, replace the brake pedal position sensor.

Repair Instructions

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

* Brake Pedal Position Sensor Calibration (Brake Pedal Position Sensor Calibration)
* Brake Pedal Position Sensor Replacement (Brake Pedal Position Sensor Replacement)