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 battery positive voltage to the stop lamps, transmission control module (TCM), engine control module (ECM), and stop lamp relay coil side. The BCM also supplies the stop lamp relay coil with ground. When the stop lamp relay receives battery voltage and ground from the BCM, the relay coil is energized and the stop lamp relay switch contacts close applying battery voltage through the STOP/B/U/LPS fuse to illuminate the center high mounted stop lamp (CHMSL).

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.

Diagnostic Aids

Note:
The stop lamps will not illuminate unless the ignition is in the ON position. For more detailed information concerning stop lamp operation, refer to Exterior Lighting Systems Description and Operation Exterior Lighting Systems.

If DTC C0278 00 is set, recalibrate the brake pedal position sensor.

Reference Information

Schematic Reference

Exterior Lights Schematics Exterior Lights Schematics

Connector End View Reference

Component Connector End Views Folding Top 5 Bow Lowered Switch (CM7)

Description and Operation

Exterior Lighting Systems Description and Operation Exterior Lighting Systems

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 Control Module References 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.

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 Replacement