Buick Regal: DTC P0572 or P0573

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 P0572

Brake Switch Circuit 1 Low Voltage

DTC P0573

Brake Switch Circuit 1 High Voltage

Diagnostic Fault Information

Circuit/System Description

For an overview of the component/system, refer to:Cruise Control Description and Operation (Without Adaptive Cruise Control) or Cruise Control Description and Operation (With Adaptive Cruise Control).

Conditions for Running the DTC

• Ignition/Vehicle=On
• Vehicle Speed.=Greater than 40 km/h (25 MPH)
• Cruise Control=On

Frequency the DTC runs=Continuously - After the running conditions are met - For greater than 5 s

Conditions for Setting the DTC

DTC P0572

Brake Pedal Position Circuit Signal - Open/Short to Ground

DTC P0573

Brake Pedal Position Circuit Signal - Short to Voltage

Actions Taken When the DTC Sets

• Cruise Control System Status=Disabled
• DTCs listed in the DTC Descriptor Category=Type C DTC

Conditions for Clearing the DTC

DTCs listed in the DTC Descriptor Category=Type C DTC

Reference Information

Schematic Reference

Cruise Control Wiring Schematics

Connector End View Reference

Component Connector End View Index

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

1. Ignition - On / Vehicle - In Service Mode.

2. Verify the component works as specified:Brake Pedal Position Sensor.

• If a related DTC is set

Refer to:Diagnostic Trouble Code (DTC) List - Vehicle

• Go to next step: If a related DTC is not set

3. Verify that no DTC listed in the DTC Descriptor Category is set.

• If a related DTC is set

Refer to Circuit/System Testing.

• Go to next step: If a related DTC is not set

4. All OK.

Circuit/System Testing

1. Use the schematics to identify the items listed below:

• Brake Pedal Position Sensor Signal@K20 Engine Control Module

2. Ignition/Vehicle & All vehicle systems - Off.

3. Disconnect the component:K20 Engine Control Module.

4. Ignition - On / Vehicle - In Service Mode.

5. Connect a test lamp between the test points:Brake Pedal Position Sensor Signal & Ground.

6. Slowly press and release the brake pedal.

Verify the test lamp turns On and Off.

• If the test lamp is always Off

1. Ignition/Vehicle & All vehicle systems - Off
2. Disconnect the component:K9 Body Control Module
3. {If equipped}Disconnect all components on the circuit:Brake Pedal Position Sensor Signal
4. Test for infinite resistance between the test points:Signal circuit terminal 12@K9 Body Control ModuleX5 & Ground
   • If less than infinite resistance - Repair the short to ground on the circuit.
   • Go to next step: If infinite resistance
5. Test for less than 2 ohms between the test points:Signal circuit terminal 12@K9 Body Control ModuleX5 & The other end of the circuit
   • If 2 ohms or greater - Repair the open/high resistance in the circuit.
   • If less than 2 ohms - Replace the component:K9 Body Control Module

• If the test lamp is always On

1. Ignition/Vehicle & All vehicle systems - Off
2. Disconnect the component:K9 Body Control Module
3. Ignition - On / Vehicle - In Service Mode
4. Test for less than 1 V between the test points:Signal circuit terminal 12@K9 Body Control ModuleX5 & Ground
   • If 1 V or greater - Repair the short to voltage on the circuit.
   • If less than 1 V - Replace the component:K9 Body Control Module

• Go to next step: If the test lamp turns On and Off

7. Replace the component:K20 Engine Control Module

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair: Diagnostic Repair Verification.

For control module replacement, programming, and setup refer to: Control Module References.

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