Diagnostic Instructions
| • | 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. |
DTC Descriptors
DTC C0277 06: Brake Pedal Position Sensor Circuit Short to Ground or OpenDTC C0277 07: Brake Pedal Position Sensor Circuit Voltage Above Threshold
DTC C0277 09: Brake Pedal Position Sensor Circuit Rate of Change Above Threshold
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Stop Lamp Relay Switch B+ | 2 | 2 | -- | -- |
Brake Pedal Position Sensor 5-Volt Reference | C0277 06, C0870 03 | C0277 06 | 1 | -- |
Brake Pedal Position Sensor Signal | C0277 06 | C0277 06 | C0277 07 | C0277 09 |
Stop Lamp Relay Control | B3903 02 | B3903 05 | B3903 05 | -- |
Center High Mounted Stop Lamp (CHMSL) Control | 2 | 2 | 2 | -- |
Left Rear Stop/Turn Lamp Control | 1 | 1 | 1 | -- |
Right Rear Stop/Turn Lamp Control | 1 | 1 | 1 | -- |
Brake Pedal Position Sensor Low Reference | -- | C0277 07 | 1 | -- |
Center High Mounted Stop Lamp (CHMSL) Ground | -- | 2 | 1 | -- |
Left Rear Stop/Turn Lamp Ground | -- | 1 | 1 | -- |
Right Rear Stop/Turn Lamp Ground | -- | 1 | 1 | -- |
Stop Lamp Relay Ground | -- | 2 | -- | -- |
1. Stop Lamps Malfunction 2. Center High Mounted Stop Lamp (CHMSL) Malfunction | ||||
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-volt 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. When the stop lamp relay receives battery voltage from the BCM, the relay coil is energized and the stop lamp relay switch contacts close applying battery voltage through the STOP LP fuse to illuminate the center high mounted stop lamp (CHMSL).
Conditions for Running the DTC
| • | Battery voltage must be between 9-16 volts. |
| • | Brakes applied. |
Conditions for Setting the DTC
C0277 06
This DTC will set for the following conditions:
| • | 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 ground or an open/high resistance in the brake pedal position sensor 5-volt reference circuit. |
C0277 07
This DTC will set for the following conditions:
| • | The BCM detects a short to battery 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. |
C0277 09
The DTC will set when the BCM detects the brake pedal position sensor signal is changing faster than possible under normal operating conditions.
Actions Taken When the DTC Sets
| • | The Service Vehicle Soon indicator is commanded ON. |
| • | When DTC C0277 is set as current, the vehicle will not start. |
| • | If the DTC sets while the vehicle is running, the BCM will activate the brake lights when the vehicles transmission is not in the PARK position and the vehicle is not accelerating. |
Conditions for Clearing the DTC
| • | 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. |
| • | 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. |
Reference Information
Schematic Reference
Connector End View Reference
Description and Operation
Exterior Lighting Systems Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Testing
C0277 06 and C0277 07
- Ignition OFF, disconnect the harness connector at the brake pedal position sensor.
- Ignition OFF, verify that a test lamp illuminates between B+ and the low reference circuit terminal C.
- Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal A and ground.
- Verify the scan tool BPP Sensor parameter is less than 0.2 volts.
- Install a 3A fused jumper wire between the signal circuit terminal B and the 5-volt reference circuit terminal A. Verify the scan tool BPP Sensor parameter is greater than 4.75 volts.
- If all circuits test normal, test or replace the brake pedal position sensor.
| ⇒ | If the test lamp does not illuminate, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the BCM. |
| ⇒ | If less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM. |
| ⇒ | If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the BCM. |
| ⇒ | If greater than the specified range, test the signal circuit terminal B for a short to voltage. If the circuit tests normal, replace the BCM. |
| ⇒ | If less than the specified range, test the signal circuit for short to ground or an open/high resistance. If the circuit tests normal, replace the BCM. |
C0277 09
- Replace the brake pedal position sensor.
- Perform the brake pedal position sensor recalibration procedure. Refer to Brake Pedal Position Sensor Calibration.
- Operate the vehicle within the Conditions for Running and Setting the DTC and verify the DTC does not reset.
| ⇒ | If the DTC resets, replace the BCM. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for BCM replacement, setup, and programming |
