P057D
DTC P057B-P057D
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions 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
Diagnostic Fault Information
Typical Scan Tool Data
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 three wire sensor, connected to a 5 V reference circuit, a low reference circuit, and a signal circuit. The ECM supplies 5 V to the BPP sensor, and also provides a sensor ground path on the low reference circuit. 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.
Conditions for Running the DTC
P057B
* DTCs P057C or P057D are not set.
* Ignition Voltage is greater than 10 V.
P057C and P057D
Ignition voltage is greater than 10 volts.
Conditions for Setting the DTC
P057B
The ECM detects the brake pedal position sensor value is stuck in midrange of the low and high learn values.
P057C
The ECM detects a short to ground for the brake pedal position sensor.
P057D
The ECM detects an open circuit for the brake pedal position sensor.
Action Taken When the DTC Sets
* DTCs P057B, P057C and P057D are type A DTCs.
* Engine torque is reduced to 50 percent of available engine torque.
* Brake torque management is active at 25 kpa (3.7 PSI) of brake pedal apply pressure.
Conditions for Clearing the DTC
DTCs P057B, P057C and P057D are type A DTCs.
Reference Information
Schematic Reference
* Automatic Transmission Controls Schematics Electrical Diagrams
* Engine Controls Schematics ((L99/LS3)) [1][2]Electrical DiagramsEngine Controls Schematics ((LSA)) [1][2]Electrical Diagrams
Connector End View Reference
* Component Connector End Views Fuel Pump and Level Sensor Assembly
* Inline Harness Connector End Views X102
Description and Operation
* Transmission General Description Transmission General Description
* Engine Control Module Description Description and Operation
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References Control Module References for scan tool information
Circuit/System Verification
1. Ignition ON, transmission in Park position, brake pedal in the release position.
2. Verify the scan tool brake pedal position sensor parameter displays greater than 0.25 V.
• If less than the specified value
Refer to Circuit/System Testing.
• If greater than the specified value
3. Fully apply the brake pedal.
4. Verify the scan tool brake pedal position sensor parameter displays less than 4.75 V.
• If greater than the specified value
Refer to Circuit/System Testing.
• If less than the specified value
5. Return the brake pedal to full release position.
6. Verify the scan tool brake pedal position sensor learned home position parameter value is within 100 mv of the brake pedal position sensor parameter value.
• If not within the specified value
refer to Brake Pedal Position Sensor Learn 6L45/6L50/6L80/6L90 - Automatic Transmission.
• If within the specified value
7. Depress and release the brake pedal.
8. Verify the scan tool brake pedal position sensor parameter value transitions smoothly and does not drop out.
• If the value does not transition smoothly or drops out
Refer to Circuit/System Testing.
• If the value does transition smoothly and does not drop out
9. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observe from the Freeze Frame/Failure Records data.
10. Verify the DTC does not set.
• If the DTC sets
Refer to Circuit/System Testing.
• If the DTC does not set
11. All OK.
Circuit/System Testing
Note: You must perform the Circuit/System Verification first.
1. Ignition OFF and all vehicle systems OFF. Disconnect the By brake pedal position sensor harness connector at the By brake pedal position sensor. It may take up to 2 minutes for all vehicle systems to power down.
2. Test for less than 10 ohms between the low reference circuit terminal 6 and ground.
• If 10 ohms or greater
1. Ignition OFF, disconnect the harness connector at the KO Engine Control Module.
2. Test for less than 2 ohms in the low reference circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms replace the KO Engine Control Module.
• If less than 10 ohms
3. Ignition ON.
4. Test for 4.8-5.2 V between the 5 V reference circuit terminal 5 and ground.
• If less than 4.8 V
1. Ignition OFF, disconnect the harness connector at the KO 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.
• If infinite resistance
3. Test for less than 2 ohms in the 5 V reference circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the KO Engine Control Module.
• If greater than 5.2 V
1. Ignition OFF, disconnect the harness connector at the KO Engine Control Module.
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 KO Engine Control Module.
• If between 4.8-5.2 V
5. Verify the scan tool brake pedal position parameter is less than 0.25 V.
• If 0.25 V or greater
1. Ignition OFF, disconnect the harness connector at the KO Control Module, Ignition ON.
2. Test for less than 1 V between the signal circuit terminal 4 and ground.
• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V, replace the KO Engine Control Module.
• 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 5.
7. Verify the scan tool brake pedal position parameter is greater than 4.75 V.
• If 4.75 V or less
1. Ignition OFF, disconnect the harness connector at the KO 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.
• If infinite resistance
3. Test for less than 2 ohms in the signal circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the KO Engine Control Module.
• If greater than 4.75 V
8. Replace the By brake pedal position sensor.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
* Perform the Brake Pedal Position Sensor Learn 6L45/6L50/6L80/6L90 - Automatic Transmission following the replacement of the ECM or BPP sensor, or any repair that effects the BPP sensor alignment.
* Control Module References Control Module References for ECM replacement, programming, and setup.