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
* DTCs P057C and P057D are type B 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 P057C and P057D are type B DTCs.
Reference Information
Schematic Reference
* Automatic Transmission Controls Schematics Electrical Diagrams
* Engine Controls Schematics (LS3) [1][2]Electrical DiagramsEngine Controls Schematics (LS9) [1][2]Electrical DiagramsEngine Controls Schematics (LS7) [1][2]Electrical Diagrams
Connector End View Reference
* Component Connector End Views Folding Top 5 Bow Lowered Switch (CM7)
* 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, engine OFF, transmission in PARK position, brake pedal released, verify with a scan tool the Brake Pedal Position Sensor parameter in the Automatic Transmission Data list displays greater than 0.25 volts.
• If less than the specified value
Refer to Circuit/System Testing below.
• If greater than the specified value
2. Brake pedal fully applied, verify with a scan tool the Brake Pedal Position Sensor Signal parameter displays less than 4.75 volts.
• If greater than the specified value
Refer to Circuit/System Testing below.
• If less than the specified value
3. Brake pedal fully released, verify with a scan tool the Brake Pedal Position Sensor Learned Home Position parameter voltage is within 100 millivolts of the Brake Pedal Position Sensor parameter voltage.
• If not within the specified value
Use a scan tool to command the Brake Pedal Position Sensor Learn .
• If within the specified value
4. Observe the Brake Pedal Position Sensor parameter and vary the brake apply position. Verify that the Brake Pedal Position parameter transitions smoothly and does not drop out.
• If the parameter value drops out or does not transition smoothly between 0.25-4.75 volts
Refer to Circuit/System Testing below.
• If the parameter value does not drop out and transitions smoothly between 0.25-4.75 volts
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 wire harness electrical connector from the B22 Brake Pedal Position Sensor.
2. Test for less than 10 ohms between the low reference circuit terminal 6 and ground.
• If greater than the specified value, test the low reference circuit for an open/high resistance
If the circuit tests normal, replace the ECM.
• If less than the specified value
3. Ignition ON, test for 4.8-5.2 V between the 5 V reference circuit terminal 5 and ground.
• If less than the specified range, test the 5 V reference circuit for a short to ground or an open/high resistance
If the circuit tests normal, replace the K20 ECM.
• If greater than the specified range, test the 5 V reference circuit for a short to voltage
If the circuit tests normal, replace the K20 ECM.
• If within the specified range
4. Verify that the scan tool Brake Pedal Position Sensor parameter is less than 0.25 volts.
• If greater than the specified value, test the signal circuit for a short to voltage
If the circuit tests normal, replace the ECM.
• If less than the specified value
5. Install a 3 A fused jumper wire between the signal circuit terminal 4 and the 5 V reference circuit terminal 5. Verify that the scan tool Brake Pedal Position Sensor parameter is between 4.8-5.2 volts.
• 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 K20 ECM.
• If within the specified range
6. If all circuits test normal, 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 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.