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
P057C and P057D
Ignition voltage is greater than 10 Volts.
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 (MH8) Electrical Diagrams
Connector End View Reference
* Component Connector End Views Sunshade - Left (DH6)
* Inline Harness Connector End Views Power Steering Control Harness to Forward Lamp Harness (NJ1)
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 6T30/6T40/6T45/6T50 - Automatic Transmission.
Circuit/System Verification
1. Ignition ON, engine OFF, transmission in PARK, service brake pedal released, verify with a scan tool the ECM Brake Pedal Position Sensor parameter in the Automatic Transmission Data list displays.25 volts or greater.
• If less than.25 volts
Refer to Circuit/System testing below.
• If.25 volts or greater
2. Service brake pedal fully applied, verify with a scan tool the Brake Pedal Position Sensor parameter displays 4.75 volts or less.
• If greater than 4.75 volts
Refer to Circuit/System Testing below.
• If 4.75 volts or less
3. Verify with a scan tool the Brake Pedal Position Sensor Learned Home Position parameter voltage is within 0.1 volts of the Brake Pedal Position Sensor parameter when the brake pedal is fully released.
• If difference is greater than 0.1 volts
Command the Brake Pedal Position Sensor Learn with a scan tool.
• If difference is 0.1 volts or less
4. 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 below.
• If parameter transitions smoothly and there are no spikes or dropouts
5. After performing the above steps, verify that the DTC does not reset by operating the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions you observe from the Freeze Frame/Failure Records data. If the vehicle passes the Circuit/System Verification procedure, then STOP. Do not perform the Circuit/System Testing or Component Testing as this may result in an unnecessary part replacement. Refer to Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections.
Circuit/System Testing
Note: You must perform the Circuit/System Verification first.
1. Ignition OFF, disconnect the harness connector from the B22 Brake Pedal Position Sensor.
2. Test for less than 10 ohms between the low reference circuit terminal 5 and ground.
• If 10 ohms or greater
Test the low reference circuit for less than 5 ohms, end to end.
• If 5 ohms or greater, repair the open/high resistance in the circuit.
• If less than 5 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 6 and ground.
• If less than 4.8 volts
Test the 5 V reference circuit for a short to ground and an open/high resistance.
• If circuit has a short to ground or open/high resistance, repair the wire in the circuit.
• If circuit does not have a short to ground or open/high resistance, replace the K20 engine control module.
• If greater than 5.2 volts
Test the 5 V reference circuit for a short to voltage.
• If circuit has a short to voltage, repair the wire in the circuit.
• If circuit does not have a short to voltage, replace the K20 engine control module.
• If within the specified range
5. Verify the scan tool Brake Pedal Position Sensor parameter is less than.25 volts.
• If parameter is.25 Volts or greater
1. Test for less than.25 volts between the signal circuit terminal 4 and ground
• If.25 volts or greater.
2. Test the signal circuit for a short to voltage.
• If signal circuit has a short to voltage, repair the wire in the circuit.
• If signal circuit does not have a short to voltage, replace the K20 engine control module.
• If less than.25 volts
3. Replace the K20 engine control module.
• If parameter is less than.25 volts
6. Install a 3 A fused jumper wire between the signal circuit terminal 4 and the 5 V reference circuit terminal 6. Verify that the scan tool Brake Pedal Position Sensor parameter is between 4.8-5.2 volts.
• If not between 4.8-5.2 V
1. Test the signal circuit for a short to ground.
• If signal circuit has a short to ground, repair the wire in the circuit.
• If signal circuit does not have a short to ground.
2. Test for less than 5 ohms in the signal circuit end to end.
• If 5 ohms or greater, repair the open/high resistance in the circuit.
• If less than 5 ohms, replace the K20 engine control module.
• If between 4.8-5.2V
7. Replace the B22 Brake Pedal Position Sensor.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
* Refer to Control Module References Control Module References for control solenoid valve assembly replacement, setup, and programming.
* Perform the Transmission Adaptive Values Learn Transmission Adaptive Values Learn following all transmission related repairs.
* Perform the Brake Pedal Position Sensor Learn following the replacement of the ECM or BPP sensor, or any repair that effects the BPP sensor alignment.