Buick Regal: DTC P057B-P057E

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 P057B

Brake Pedal Position Sensor Performance

DTC P057C

Brake Pedal Position Sensor Circuit Low Voltage

DTC P057D

Brake Pedal Position Sensor Circuit High Voltage

DTC P057E

Brake Pedal Position Sensor Circuit Erratic

Diagnostic Fault Information

Typical Scan Tool Data

Brake Pedal Position Sensor

Circuit/System Description

The brake pedal position (BPP) sensor is part of the engine brake pedal override feature. The engine control module (ECM) continuously monitors the vehicle speed and the position of the brake pedal.

These two main inputs, along with other ECM inputs are used to determine if the vehicle is decelerating at the proper speed and rate with the brake pedal applied. When the engine brake pedal override system is active, the ECM reduces engine torque to assist in reducing vehicle speed.

The BPP sensor is a six wire sensor, and is part of a dual brake position sensor. One BPP Sensor is used for the stop lamps and the other BPP Sensor is used for the engine brake pedal override feature. The BPP Sensor for engine brake pedal override communicates with the ECM. The ECM supplies a 5 V reference circuit, low reference circuit, and signal circuit to the BPP sensor. The BPP sensor sends a voltage signal to the ECM on the signal circuit. The voltage on the signal circuit will vary from a voltage greater than 0.25 V when the brake pedal is released to a voltage less than 4.75 V when the brake pedal is fully applied.

For information on the Stop Lamps side of the BPP Sensor, refer to Exterior Lighting Systems Description and Operation.

Conditions for Running the DTC

P057B

• DTCs P057C, or P057D are not set.
• Ignition voltage is greater than 10 V.
• Shift lever has been in Park at least once during key ON.
• Shift lever is not in Park.
• Vehicle speed is greater than 8 Km/h (5 mph).
• Accelerator Pedal Position is less than 5 %.
• DTC runs once per key cycle when above conditions are met.

P057C, P057D, or P057E

• Ignition voltage is greater than 10 V.
• DTC runs continuously when above condition is met.

Conditions for Setting the DTC

P057B

ECM detects the BPP sensor signal is stuck in a range for greater than 1 s.

P057C

ECM detects the BPP sensor voltage is less than 0.25 V greater than 1 s.

P057D

ECM detects the BPP sensor voltage is greater than 4.75 V greater than 1 s.

P057E

ECM detects the BPP sensor value varies greater than a calibrated value.

Action Taken When the DTC Sets

• P057B, P057C, P057D, and P057E are Type A DTCs.
• Brake Pedal Position Sensor parameter defaults to 0 %.

Conditions for Clearing the DTC

P057B, P057C, P057D, and P057E are Type A DTCs

Reference Information

Schematic Reference

• Engine Controls Wiring Schematics (LTG)
• Exterior Lights Wiring Schematics

Connector End View Reference

• Component Connector End View Index
• Inline Harness Connector End View Index

Electrical Information Reference

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

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

NOTE: The Brake Pedal Position sensor scan tool data is located in the ECM automatic transmission data list.

1. Ignition ON.

2. Verify DTC P0641, P0651, P0697, or P06A3 is not set.

• If any of the DTCs are set

Refer to DTC P0641, P0651, P0697, P06A3, or P06D2.

• Go to next step: If none of the DTCs are set

3. Transmission in Park, and service brake pedal released.

4. Verify the scan tool Brake Pedal Position Sensor parameter in the ECM displays greater than 0.25 V.

• If 0.25 V or less

Refer to Circuit/System Testing.

• Go to next step: If greater than 0.25 V

5. Verify the scan tool Brake Pedal Position Sensor parameter voltage changes as the brake pedal is applied and displays less than 4.75 V when the brake pedal is fully applied.

• If the voltage does not change, or is greater than 4.74 V

Refer to Circuit/System Testing.

• Go to next step: If the voltage changes and less than 4.75 V

6. Verify the scan tool Brake Pedal Position Sensor Learned Release Position parameter is within 0.1 V of the Brake Pedal Position Sensor parameter when the brake pedal is fully released.

• If difference is greater than 0.1 V

Perform the Brake Pedal Position Sensor Calibration.

• Go to next step: If difference is 0.1 V or less

7. Verify the Brake Pedal Position Sensor parameter transitions smoothly without any spikes or dropouts when slowly applying and releasing the brake pedal.

• If parameter does not transition smoothly or has spikes or dropouts

Refer to Circuit/System Testing.

• Go to next step: If parameter transitions smoothly and there are no spikes or dropouts

8. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

9. Verify the DTC does not set.

• If the DTC sets

Refer to Circuit/System Testing.

• Go to next step: If the DTC does not set

10. All OK.

Circuit/System Testing

NOTE: You must perform the Circuit/System Verification first.

1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the B22 Brake Pedal Position Sensor. It may take up to 2 minutes for all vehicle systems to power down.

NOTE: All terminal references are for the vehicle harness brake pedal position sensor connector.

2. Test for less than 10 Ω between the low reference circuit terminal 5 and ground.

• If 10 Ω or greater

1. Disconnect the harness connector at the K20 Engine 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 K20 Engine Control Module.

• Go to next step: If less than 10 Ω

3. Ignition ON.

4. Test for 4.8 - 5.2 V between the 5 V reference circuit terminal 6 and ground.

• If less than 4.8 V

1. Ignition OFF, disconnect the harness connector at the K20 Engine 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.
   • Go to next step: 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 K20 Engine Control Module.

• If greater than 5.2 V

1. Ignition OFF, disconnect the harness connector at the K20 Engine 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 K20 Engine Control Module.

• Go to next step: If between 4.8 - 5.2 V

5. Verify the scan tool Brake Pedal Position Sensor parameter is less than 0.25 V.

• If 0.25 V or greater

1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module, ignition ON.
2. Test for less than 0.25 V between the signal circuit terminal 4 and ground.
   • If 0.25 V or greater, repair the short to voltage on the circuit.
   • If less than 0.25 V, replace the K20 Engine Control Module.

• Go to next step: If less than 0.25 V

6. Install a 3 A fused jumper wire between the signal circuit terminal 4 and the 5 V reference circuit terminal 6.

7. Verify the scan tool Brake Pedal Position Sensor parameter is greater than 4.8 V.

• If 4.8 V or less

1. Ignition OFF, remove the jumper wire, and disconnect the harness connector at the K20 Engine Control Module.
2. Test for infinite resistance between the signal circuit terminal 4 and ground.
   • If less than infinite resistance, repair the short to ground on the circuit.
   • Go to next step: 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 K20 Engine Control Module.
   • Go to next step: If greater than 4.8 V

8. Replace the B22 Brake Pedal Position Sensor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

• Brake Pedal Position Sensor Replacement
• Perform the Brake Pedal Position Sensor Calibration following the replacement of the ECM or BPP sensor, or any repair that effects the BPP sensor alignment.
• Control Module References for Engine Control Module replacement, programming and setup.

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