GM Service Manual Online
For 1990-2009 cars only

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: Brake Pedal Position Sensor Circuit

DTC C0278: Brake Pedal Position Sensor Not Calibrated

DTC C0283: Brake Pedal Position Sensor Circuit Low

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Brake Pedal Position Sensor 10-Volt Reference

C0283, C0870

C0277

C0277

--

Brake Pedal Position Sensor Signal

C0283

C0277

C0277

--

Brake Pedal Position Sensor Low Reference

--

C0277

1

--

1. Stop Lamps 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 10-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 stop lamps, transmission control module (TCM), engine control module (ECM), electronic brake control module (EBCM), and 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

DTC C0277 will set for the following conditions:

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

DTC C0278 will set when the brake pedal position sensor home position is not learned.

Action 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.
    • A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

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 .

Reference Information

Schematic Reference

Exterior Lights Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Exterior Lighting Systems Description and Operation

Electrical Information Reference

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

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Testing

DTC C0277 or C0283

  1. Ignition OFF, disconnect the harness connector at the brake pedal position sensor.
  2. Ignition OFF, verify that a test lamp illuminates between B+ and the low reference circuit terminal A.
  3. 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.
  4. Ignition ON, test for 9.8-10.2 volts between the 10-volt reference circuit terminal A and ground.
  5. If greater than the specified range, test the 10-volt reference circuit for a short to voltage. If the circuit tests normal, replace the BCM.
    If less than the specified range, test the 10-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  6. Verify the scan tool BPP Sensor parameter is less than 4 counts.
  7. 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.
  8. Install a 3A fused jumper between the signal circuit terminal B and the 10-volt reference circuit terminal A. Verify the scan tool BPP Sensor parameter is greater than 250 counts.
  9. If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  10. If all circuits test normal, test or replace the brake pedal position sensor.

DTC C0278

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

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

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