WOMS
B code body Medium severity

B1571 Door Ajar LR Circuit Failure

The OBD2 code B1571 Door Ajar LR Circuit Failure indicates a malfunction in the left rear door ajar switch circuit, suggesting that the vehicle's system is detecting an issue with the door's open/closed status

Definition

The OBD2 code B1571 Door Ajar LR Circuit Failure indicates a malfunction in the left rear door ajar switch circuit, suggesting that the vehicle's system is detecting an issue with the door's open/closed status

Common causes

  • Faulty door ajar switch
  • Damaged wiring or connectors
  • Short circuit in the circuit
  • Open circuit in the circuit
  • Corroded terminals
  • Malfunctioning body control module (BCM)
  • Misaligned door or latch mechanism

Common misdiagnoses

  • Faulty door latch assembly
  • Malfunctioning door switch
  • Wiring issues or shorts in the circuit
  • Body control module (BCM) failure
  • Incorrectly installed or damaged door seal
  • Faulty ground connection
  • Issues with the vehicle's alarm system
  • Problems with the instrument cluster or dashboard indicators

Troubleshooting steps

  1. 1. Visual Inspection

    Check the Door Ajar Switch: Inspect the left rear door ajar switch for any visible damage or wear. Ensure that it is properly mounted and not stuck in the "open" position

  2. 2. Wiring Inspection

    Look for any damaged, frayed, or corroded wiring in the door harness. Pay special attention to the connectors and terminals

  3. 3. Test the Door Ajar Switch

    Multimeter Test: Use a multimeter to test the door ajar switch. With the door closed, the switch should show continuity (closed circuit). When the door is open, it should show no continuity (open circuit)

  4. 4. Manual Activation

    Manually activate the switch (if possible) to see if it changes the status on the dashboard or triggers the warning light

  5. 5. Check for Faulty Connections

    Connector Inspection: Ensure that all connectors related to the door ajar switch are clean and securely connected. Look for any signs of corrosion or loose connections

  6. 6. Ground Connections

    Check the ground connections for the door ajar circuit to ensure they are secure and free of corrosion

  7. 7. Scan for Additional Codes

    Check for Other Codes: Use an OBD-II scanner to check for any additional trouble codes that may provide more context or indicate related issues

  8. 8. Inspect the Body Control Module (BCM)

    BCM Functionality: The BCM often processes the signals from the door ajar switches. If other troubleshooting steps do not resolve the issue, consider checking the BCM for faults or software updates

  9. 9. Perform a System Reset

    Clear Codes: After performing any repairs or adjustments, clear the trouble codes using an OBD-II scanner and see if the code returns after a test drive

  10. 10. Consult Wiring Diagrams

    Refer to Service Manual: If the issue persists, consult the vehicle’s service manual for wiring diagrams and specific troubleshooting procedures related to the door ajar circuit

  11. 11. Professional Diagnosis

    Seek Help if Needed: If you are unable to resolve the issue after these steps, consider seeking assistance from a professional mechanic or automotive technician who can perform more advanced diagnostics. By following these steps, you should be able to identify and resolve the issue related to the B1571 code