• 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 provides an overview of each diagnostic category.

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 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 voltage to the stop lamp control circuit and center high mounted stop lamp control circuit . When the control circuit is energized the stop lamps are illuminated.

• Battery voltage must be between 9–16 V.
• Brakes APPLIED.

• The BCM detects a short to ground or an open/high resistance in the brake pedal position sensor 5 V reference circuit.
• The BCM detects a short to ground or an open/high resistance in the brake pedal position sensor signal circuit.

• The BCM detects a short to voltage in the brake pedal position sensor 5 V reference circuit.
• The BCM detects a short to voltage in the brake pedal position sensor signal circuit.
• The BCM detects an open/high resistance in the brake pedal position sensor low reference circuit.

The BCM detects the brake pedal position sensor signal is changing faster than possible under normal operating conditions.

The DTC will set when the brake pedal position sensor home position is not learned.

• The BCM detects a short to ground in the brake pedal position sensor 5 V reference circuit.
• The BCM detects a short to ground or an open/high resistance in the F23DA (BCM 1) fuse B+ circuit.

• The BCM detects a short to voltage in the brake pedal position sensor 5 V reference circuit.
• The BCM detects a short to voltage in the brake pedal position sensor low reference circuit.

• The Traction Control indicator is commanded ON.
• For DTC C0277 4B, the stop lamps may not activate at the expected brake pedal positions.

• The condition responsible for setting the DTC no longer exists.
• For DTC C0277 07 the ignition must be cycled before the code can be cleared.
• For DTC C0277 4B a successful brake pedal position sensor calibration has been performed.
• A history DTC will clear once 50 malfunction-free ignition cycles have occurred.
• A DTC will not clear the current status until the next ignition cycle.

Exterior Lights Schematics

Master Electrical Component List

Exterior Lighting Systems Description and Operation

• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs

Control Module References for scan tool information

1. Ignition OFF, disconnect the harness connector at the B22 Brake Pedal Position Sensor, ignition ON.
2. Verify a test lamp illuminates between the low reference circuit terminal 2 and B+.
• If the test lamp does not illuminate
1. Ignition OFF, disconnect the X1 harness connector at the K9 Body Control Module.
2. Test for less than 2 Ω in the low reference circuit end to end.
• If 2 Ω or greater, repair the open/high resistance in the circuit.
• If less than 2 Ω, replace the K9 Body Control Module.
• If the test lamp illuminates
3. Ignition ON.
4. Test for 4.8–5.2 V between the 5 V reference circuit terminal 1 and ground.
• If less than 4.8 V
1. Ignition OFF, disconnect the X2 harness connector at the K9 Body Control Module.
2. Test for infinite resistance between the 5 V reference circuit and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance
3. Test for less than 2 Ω in the 5 V reference circuit end to end.
• If 2 Ω or greater, repair the open/high resistance in the circuit.
• If less than 2 Ω, replace the K9 Body Control Module.
• If greater than 5.2 V
1. Ignition OFF, disconnect the X2 harness connector at the K9 Body Control Module, ignition ON.
2. Test for less than 1 V between the 5 V reference circuit and ground.
• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V, replace the K9 Body Control Module.
• If between 4.8–5.2 V
5. Verify the scan tool Brake Pedal Applied parameter is Inactive.
• If not Inactive
1. Ignition OFF, disconnect the X2 harness connector at the K9 Body Control Module, ignition ON.
2. Test for less than 1 V between the signal circuit terminal 3 and ground.
• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V, replace the K9 Body Control Module.
• If Inactive
6. Install a 3 A fused jumper wire between the 5 V reference circuit terminal 1 and signal circuit terminal 3.
7. Verify the scan tool Brake Pedal Applied parameter is Active.
• If not Active
1. Ignition OFF, disconnect the X2 harness connector at the K9 Body Control Module.
2. Test for infinite resistance between the signal circuit and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance
3. Test for less than 2 Ω in the signal circuit end to end.
• If 2 Ω or greater, repair the open/high resistance in the circuit.
• If less than 2 Ω, replace the K9 Body Control Module.
• If Active
8. Perform the brake pedal position sensor learn procedure for the K9 Body Control Module. Refer to Brake Pedal Position Sensor Calibration.
9. Verify the DTC does not reset while operating the vehicle under the conditions for running the DTC.
• If the DTC resets, replace the B22 Brake Pedal Position sensor.
• If the DTC does not reset
10. All OK.

1. Verify DTC C0277 4B is not set.
• If DTC C0277 4B is set
1. Ignition ON
2. Perform the brake pedal position sensor learn procedure for the K9 Body Control Module. Refer to Brake Pedal Position Sensor Calibration.
3. Verify the DTC does not reset while operating the vehicle under the conditions for running the DTC.
• If the DTC resets, replace the B22 Brake Pedal Position sensor.
• If the DTC does not reset
4. All OK.
• If DTC C0277 4B is not set
2. All OK.

1. Verify DTC C0277 09 and C0277 12 are not set.
• If DTC C0277 09 or C0277 12 is set
1. Replace the B22 Brake Pedal Position sensor.
2. Perform the brake pedal position sensor learn procedure for the K9 Body Control Module. Refer to Brake Pedal Position Sensor Calibration.
3. Verify the DTC does not reset while operating the vehicle under the conditions for running the DTC.
• If the DTC resets, replace the K9 Body Control Module.
• If the DTC does not reset
4. All OK.
• If DTC C0277 09 or C0277 12 is not set
2. All OK.

Perform the Diagnostic Repair Verification after completing the repair.

• Brake Pedal Position Sensor Replacement
• Brake Pedal Position Sensor Calibration
• Control Module References for BCM replacement, programming, and setup