P057C
DTC P057C or 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 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
Ignition voltage is greater than 10 V.
Conditions for Setting the DTC
P057C
BPP sensor voltage is less than 0.25 V for 1 second
P057D
BPP sensor voltage is greater than 4.75 V for 1 second.
Action Taken When the DTC Sets
* P057C and P057D are type B DTCs
* Engine torque is reduced to 50 percent of available engine torque during torque management.
* Brake torque management is active at 25 kPa (3.7 PSI) of brake apply pressure.
Conditions for Clearing the DTC
P057C and P057D are type B DTCs.
Reference Information
Schematic Reference
* Automatic Transmission Controls Schematics Electrical Diagrams
* Exterior Lights Schematics Exterior Lights Schematics
Connector End View Reference
* Component Connector End Views Fuel Pump and Level Sensor Assembly
* Inline Harness Connector End Views X100
Description and Operation
* Transmission General Description Transmission General Description
* Transmission Component and System Description Transmission Component and System Description
* Electronic Component Description Electronic Component Description
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
Special Tools
DT-48616-10 - Adapter Harness
For equivalent regional tools, refer to Special Tools Tools and Equipment.
Circuit/System Verification
1. Ignition ON, engine OFF, transmission in PARK, service brake pedal released.
2. Verify the scan tool engine control module Brake Pedal Position Sensor parameter in the Automatic Transmission Data list displays greater than.25 V.
• If.25 V or less
Refer to Circuit/System testing.
• If greater than.25 V
3. Verify the scan tool Brake Pedal Position Sensor parameter changes as the brake pedal is applied and displays less than 4.75 V when the brake pedal is fully applied.
• If 4.75 V or greater, or the parameter does not change
Refer to Circuit/System Testing.
• If less than 4.75 V and parameter changes
4. Verify the scan tool Brake Pedal Position Sensor Learned Home 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
Command the Brake Pedal Position Sensor Learn 6T30/6T40/6T45/6T50 (MH8, MH9) - Automatic Transmission with a scan tool.
• If difference is 0.1 V or less
5. Verify the Brake Pedal Position parameter transitions smoothly without any spikes or dropouts when slowly applying and releasing the brake.
• If parameter does not transition smoothly or has spikes or dropouts
Refer to Circuit/System Testing.
• If parameter transitions smoothly and there are no spikes or dropouts
6. 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.
7. Verify the DTC does not set.
• If the DTC sets
Refer to Circuit/System Testing.
• If the DTC does not set
8. 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 from 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 electrical connector.
2. Test for less than 10 ohms between the low reference circuit terminal 6 and ground.
• If 10 ohms or greater
1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the K20 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 K20 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 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.
• 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 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.
• If between 4.8-5.2 V
5. Verify the scan tool Brake Pedal Position Sensor parameter is less than.25 V.
• If parameter is.25 V or greater
1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module, ignition ON.
2. Test for less than.25 V between the signal circuit terminal 4 and ground.
• If.25 V or greater, repair the short to voltage on the circuit.
• If less than.25 V, replace the K20 Engine Control Module.
• If less than.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 Sensor parameter is 4.8 V or greater.
• 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 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 K20 Engine Control Module.
8. Replace the B22 Brake Pedal Position Sensor.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
* Perform the Brake Pedal Position Sensor Learn 6T30/6T40/6T45/6T50 (MH8, MH9) - 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 control solenoid valve assembly replacement, programming and setup.