Engine Controls and Fuel - 3.0L LM2 Diesel | Diagnostic Information and Procedures | Document ID: 5499666
Diagnostic Instructions
Perform the Diagnostic System Check prior to using this diagnostic procedure: Diagnostic
System Check - Vehicle
Review the description of Strategy Based Diagnosis: Strategy Based Diagnosis
An overview of each diagnostic category can be found here: Diagnostic Procedure
Instructions
DTC Descriptor
DTC P057B
Brake Pedal Position Sensor Performance
DTC P057C
Brake Pedal Position Sensor Circuit Low
DTC P057D
Brake Pedal Position Sensor Circuit High
DTC P057E
Brake Pedal Position Sensor Circuit Erratic
Diagnostic Fault Information
| Circuit |
Short to Ground |
Open/High Resistance |
Short to Voltage |
Signal Performanc |
| 5 V Reference |
P057C, P0651* |
P057C |
P0651* |
— |
| Signal |
P057C |
P057C |
P057D |
P057B |
| Low Reference |
— |
P057D |
— |
— |
| * Additional DTCs may set |
|
|
|
|
Typical Scan Tool Data
Brake Pedal Position Sensor
| Circuit |
Short to Ground |
Open |
Short to Voltage |
| Operating Conditions: Ignition = On Parameter Normal Range: 0.7 to 2.7 V |
|
|
|
| 5 V Reference |
0 V |
0 V |
2.2 V |
| Signal |
0 V |
0 V |
5 V |
| Low Reference |
— |
5 V |
— |
| Circuit |
Description |
| 5 V Reference |
Regulated voltage supplied by the control module. |
| Signal |
The control module input circuit has an internal resistance connected to ground. |
| Low Reference |
Grounded through the control module. |
| Component |
Description |
| B22 Brake Pedal Position Sensor |
The input voltage varies depending on the position of the sensor. |
| K20 Engine Control Module |
The control module controls a series of actuators to ensure optimal engine performance. The control module does this by reading values from a variety of sensors, interprets the data and adjusts the engine actuators accordingly. |
The pedal assembly contains 2 potentiometer-type brake pedal position sensors. When the pedal
is pressed, the voltage of one sensor goes up and the voltage of the other sensor goes down.
Conditions for Running the DTC
P057B
DTC P057C, P057D = Not set
Accelerator Pedal Position = Less than 5%
Ignition Voltage = Greater than 10 V
Shift Lever = Not in Park
Shift Lever = Park — At least 1 time(s) during the ignition cycle
Vehicle Speed = Greater than 8 km/h (5 MPH)
Frequency the DTC runs = Once — After the running conditions are met
P057C, P057D, P057E
Ignition Voltage = Greater than 10 V
Frequency the DTC runs = Continuously — After the running conditions are met
Conditions for Setting the DTC
P057B
Brake Pedal Position Sensor = Stuck in range — For greater than 1 s
P057C
Brake Pedal Position Sensor = Less than 0.25 V — For greater than 1 s
P057D
Brake Pedal Position Sensor = Greater than 4.75 V — For greater than 1 s
P057E
Brake Pedal Position Sensor = Signal noisy or erratic
Actions Taken When the DTC Sets
DTCs listed in the DTC Descriptor category = Type A DTC
Conditions for Clearing the DTC
DTCs listed in the DTC Descriptor category = Type A DTC
Reference Information
Schematic Reference
Engine Controls Schematics
Connector End View Reference
Master Electrical Component List
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
Circuit/System Verification
- Ignition » On / Vehicle » In Service Mode
- Verify the scan tool parameter: Brake Pedal Position Sensor = 0.26 to 4.74 V
⇒ If not between 0.26 and 4.74 V
Refer to: Circuit/System Testing
⇓ If between 0.26 and 4.74 V
- Verify the scan tool parameter: Brake Pedal Position Sensor = The value should change while
moving the sensor through the entire range.
⇒ If the value does not change
Refer to: Circuit/System Testing
⇓ If the value changes
- Verify the scan tool parameter: Brake Pedal Position Sensor = The value should not spike or
drop out.
Perform the action while monitoring the parameter:
Wiggle the harness and connector: B22 Brake Pedal Position Sensor
Wiggle the harness and connector: K20 Engine Control Module
⇒ If the value spikes or drops out
Repair as necessary » Wiring / Terminal(s) / Electrical Connector(s)
⇓ If the value does not spike or drop out
- 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.
Verify the DTC does not set.
⇒ If the DTC sets
Refer to: Circuit/System Testing
⇓ If the DTC is not set
- All OK.
Circuit/System Testing
- Ignition/Vehicle & All vehicle systems » Off
- Disconnect the electrical connector: B22 Brake Pedal Position Sensor
- Test for less than 10 Ω between the test points: Low Reference circuit terminal 5 & Ground
⇒ If 10 Ω or greater
3.1. Disconnect the appropriate electrical connector: K20 Engine Control Module
3.2. Test for less than 2 Ω between the test points: Low Reference circuit terminal 5 @
Component harness & The other end of the circuit @ Control module harness
⇒ If 2 Ω or greater » Repair the open/high resistance in the circuit.
⇒ If less than 2 Ω » Replace the component: K20 Engine Control Module
⇓ If less than 10 Ω
- Ignition » On / Vehicle » In Service Mode
- Test for 4.8 to 5.2 V between the test points: 5 V Reference circuit terminal 6 & Low Reference
circuit terminal 5
⇒ If less than 4.8 V
5.1. Ignition/Vehicle » Off
5.2. Disconnect the appropriate electrical connector: K20 Engine Control Module
5.3. Test for infinite resistance between the test points: 5 V Reference circuit terminal 6 @
Component harness & Ground
⇒ If less than infinite resistance » Repair the short to ground on the circuit.
⇓ If infinite resistance
5.4. Test for less than 2 Ω between the test points: 5 V Reference circuit terminal 6 @
Component harness & The other end of the circuit @ Control module harness
⇒ If 2 Ω or greater » Repair the open/high resistance in the circuit.
⇒ If less than 2 Ω » Replace the component: K20 Engine Control Module
⇒ If greater than 5.2 V
5.1. Ignition/Vehicle » Off
5.2. Disconnect the appropriate electrical connector: K20 Engine Control Module
5.3. Ignition » On / Vehicle » In Service Mode
5.4. Test for less than 1 V between the test points: 5 V Reference circuit terminal 6 @
Component harness & Ground
⇒ If 1 V or greater » Repair the short to voltage on the circuit.
⇒ If less than 1 V » Replace the component: K20 Engine Control Module
⇓ If between 4.8 and 5.2 V
- Verify the scan tool parameter: Brake Pedal Position Sensor = Less than 0.25 V
⇒ If 0.25 or greater
6.1. Ignition/Vehicle » Off
6.2. Disconnect the appropriate electrical connector: K20 Engine Control Module
6.3. Ignition » On / Vehicle » In Service Mode
6.4. Test for less than 1 V between the test points: Signal circuit terminal 4 @ Component
harness & Ground
⇒ If 1 V or greater » Repair the short to voltage on the circuit.
⇒ If less than 1 V » Replace the component: K20 Engine Control Module
⇓ If less than 0.25 V
- Connect a 3 A fused jumper wire between the test points: Signal circuit terminal 4 & 5 V
Reference circuit terminal 6
- Verify the scan tool parameter: Brake Pedal Position Sensor = Greater than 4.8 V
⇒ If 4.8 V or less
8.1. Ignition/Vehicle » Off & Remove » Jumper wire(s)
8.2. Disconnect the appropriate electrical connector: K20 Engine Control Module
8.3. Test for infinite resistance between the test points: Signal circuit terminal 4 @ Component
harness & Ground
⇒ If less than infinite resistance » Repair the short to ground on the circuit.
⇓ If infinite resistance
8.4. Test for less than 2 Ω between the test points: Signal circuit terminal 4 @ Component
harness & The other end of the circuit @ Control module harness
⇒ If 2 Ω or greater » Repair the open/high resistance in the circuit.
⇒ If less than 2 Ω » Replace the component: K20 Engine Control Module
⇓ If greater than 4.8 V
- Test or replace the component: B22 Brake Pedal Position Sensor
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair: Diagnostic Repair
Verification
Brake Pedal Position Sensor Replacement
For control module replacement, programming, and setup refer to: Control Module
References