WOMS
P code powertrain Medium severity

P1571 Brake Switch Malfunction

The OBD2 code P1571 indicates a malfunction in the brake switch circuit, which may affect the vehicle's ability to detect when the brake pedal is pressed, potentially impacting features like cruise control and stability...

Definition

The OBD2 code P1571 indicates a malfunction in the brake switch circuit, which may affect the vehicle's ability to detect when the brake pedal is pressed, potentially impacting features like cruise control and stability control

Common causes

  • Faulty brake switch
  • Wiring issues (shorts or open circuits)
  • Poor electrical connections
  • Malfunctioning brake pedal assembly
  • Faulty engine control module (ECM)
  • Corroded connectors
  • Incorrectly adjusted brake switch
  • Failed cruise control system components

Common misdiagnoses

  • Faulty brake light bulbs
  • Defective brake light switch
  • Malfunctioning ABS module
  • Wiring issues or shorts in the brake light circuit
  • Faulty engine control module (ECM)
  • Problems with the cruise control system
  • Issues with the transmission range sensor
  • Faulty accelerator pedal position sensor

Troubleshooting steps

  1. 1. Check the Brake Light Switch:

    Visual Inspection: Inspect the brake light switch for any visible damage or disconnection. Ensure that it is properly mounted and aligned

  2. 2. Functionality Test

    Press the brake pedal and check if the brake lights illuminate. If they do not, the switch may be faulty

  3. 3. Inspect Wiring and Connectors:

    Wiring Inspection: Look for damaged, frayed, or corroded wires leading to the brake switch. Repair or replace any damaged wiring

  4. 4. Connector Check

    Ensure that all connectors are secure and free of corrosion. Clean or replace connectors as necessary

  5. 5. Test the Brake Light Switch:

    Multimeter Test: Use a multimeter to test the brake light switch for continuity. When the switch is pressed, it should show continuity. If it does not, the switch may need to be replaced

  6. 6. Check for Related Codes:

    Scan for Additional Codes: Use an OBD-II scanner to check for any other related trouble codes that may provide more context to the issue

  7. 7. Inspect the Brake System:

    Brake Fluid Level: Ensure that the brake fluid level is adequate, as low fluid can sometimes trigger warning codes

  8. 8. Brake Pedal Position Sensor

    If equipped, check the brake pedal position sensor for proper operation

  9. 9. Clear the Code:

    After performing repairs or replacements, clear the trouble code using an OBD-II scanner and take the vehicle for a test drive to see if the code returns

  10. 10. Check for Software Updates:

    Manufacturer Updates: Sometimes, manufacturers release software updates that can resolve issues related to the brake switch. Check with a dealership for any available updates

  11. 11. Consult a Professional:

    If the issue persists after performing the above steps, it may be necessary to consult a professional mechanic for further diagnosis. They may have specialized tools and knowledge to identify more complex issues.Conclusion: By following these troubleshooting steps, you can often identify and resolve the cause of the P1571 code. Always ensure safety when working on vehicle electrical systems, and consult a professional if you are unsure about any steps