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
DTC C0277 4B: Brake Pedal Position Sensor Calibration Not Learned
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Body Control Module (BCM) 5 Fuse B+ Supply | 1, 2 | 1, 2 | -- | -- |
Body Control Module (BCM) 6 Fuse B+ Supply | 1, 2 | 1, 2 | -- | -- |
Center High Mounted Stop Lamp (CHMSL) Control | B3445 00 | 2 | 2 | -- |
Brake Position Sensor Signal | C0277 06, 07 | C0277 06 | C0277 07 | C0277 09 |
Stop Lamp Relay Control - Export | B3445 00 | 2 | 2 | -- |
Stop Lamp Relay Switch B+ - Export | 2 | 2 | -- | -- |
Brake Position Sensor 5-Volt Reference | C0277 06, C0890 03 | C0277 06, C0890 03 | 1, 2 | -- |
Brake Position Sensor Low Reference | -- | C0277 06 | 1, 2 | -- |
Left Rear Stop/Turn Lamp Supply Voltage | 1, 2 | 1, 2 | 1, 2 | -- |
Right Rear Stop/Turn Lamp Supply Voltage | 1, 2 | 1, 2 | 1, 2 | -- |
Center High Mounted Stop Lamp (CHMSL) Ground | -- | 1, 2 | 1, 2 | -- |
Left Rear Stop/Turn Lamp Ground | -- | 1, 2 | 1, 2 | -- |
Right Rear Stop/Turn Lamp Ground | -- | 1, 2 | 1, 2 | -- |
Stop Lamp Relay Ground - Export | -- | 2 | 2 | -- |
| ||||
Circuit/System Description
Domestic
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 voltage to the right and left stop lamp control circuits, transmission control module (TCM), engine control module (ECM), and center high mounted stop lamp (CHMSL) control circuit. For more detailed information concerning stop lamp operation refer to Exterior Lighting Systems Description and Operation .
Export
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 voltage to stop lamp relay coil side control circuit, transmission control module (TCM), engine control module (ECM), and center high mounted stop lamp (CHMSL). 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 from the STOP LAMPS fuse to illuminate the rear stop lamps and trailer stop lamps. For more detailed information concerning stop lamp operation refer to Exterior Lighting Systems Description and Operation .
Conditions for Running the DTC
Battery voltage must be between 9-16 volts.
Conditions for Setting the DTC
C0277 06
The DTC will set when the BCM detects an open or short to ground in the brake pedal position sensor signal circuit for 0.5 second or greater.
C0277 07
The DTC will set when the BCM detects a short to battery voltage or a short to ground in the brake pedal position sensor signal or low reference circuits for 0.5 seconds or greater.
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.
C0277 4B
The DTC will set when the brake pedal position sensor home position is not learned.
Actions Taken When the DTC Sets
| • | The Service Vehicle Soon indicator is commanded ON. |
| • | 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. |
| • | For DTC C0277 4B the stop lamps may not activate at the expected brake pedal positions. |
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. |
| • | For DTC C0277 4B a successful brake pedal position sensor calibration has been performed. |
| • | You issue a scan tool CLEAR DTCs command. |
| • | 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. |
Diagnostic Aids
Important: 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 .
C0277 09
If the DTC is set, replace the brake pedal position sensor. If the DTC resets, replace the BCM.
C0277 4B
If the DTC is set, recalibrate the brake pedal position sensor.
Reference Information
Schematic Reference
Connector End View Reference
Lighting Systems Connector End Views
Electrical Information Reference
Scan Tool Reference
Circuit/System Testing
- 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 B.
- Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal C and ground.
- Verify the scan tool BPP sensor parameter is less than 2 counts.
- Install a 3A fused jumper wire between the signal circuit terminal A and the 5-volt reference circuit terminal C. Verify the scan tool BPP sensor parameter is greater than 1000 counts.
- 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 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 A 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.
- 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. |
C0277 4B
- Verify that the DTC sets under the Conditions for Running and Setting.
- Perform the brake pedal position sensor recalibration procedure.
- 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 after completing the diagnostic procedure.
| • | Control Module References for BCM replacement, setup, and programming |
