WOMS
B code body Medium severity

B1574 Door Ajar LR Circuit Short To Ground

The OBD2 code B1574 indicates a short circuit to ground 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 B1574 indicates a short circuit to ground 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

  • Damaged wiring or connectors in the door ajar circuit
  • Faulty door ajar switch
  • Short circuit in the wiring harness
  • Corrosion or poor connections at the door switch or connector
  • Malfunctioning body control module (BCM)
  • Water intrusion or moisture in the door or wiring

Common misdiagnoses

  • Faulty door switch
  • Wiring issues
  • Body control module (BCM) failure
  • Shorted wiring harness
  • Malfunctioning door latch assembly
  • Corroded connectors
  • Incorrectly installed or damaged door seal
  • Faulty BCM programming or software issues

Troubleshooting steps

  1. 1. Visual Inspection

    Check Wiring and Connectors: Inspect the wiring harness and connectors leading to the left rear door ajar switch for any signs of damage, fraying, or corrosion

  2. 2. Look for Shorts

    Check for any exposed wires that may be touching the vehicle's chassis or other components, which could cause a short to ground

  3. 3. Test the Door Ajar Switch

    Functionality Check: Manually operate the door ajar switch (usually located in the door latch mechanism) to see if it functions correctly. You can do this by opening and closing the door and observing if the interior lights or dashboard indicators respond appropriately

  4. 4. Continuity Test

    Use a multimeter to check for continuity in the switch. When the door is closed, the switch should show continuity (closed circuit), and when the door is open, it should not (open circuit)

  5. 5. Check for Ground Issues

    Ground Connections: Ensure that the ground connections for the door ajar switch and related components are secure and free of corrosion

  6. 6. Test Ground Circuit

    Use a multimeter to check the ground circuit for continuity and ensure it is not shorted to the vehicle's chassis

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

    BCM Functionality: If the wiring and switch are functioning correctly, the issue may lie within the Body Control Module. Check for any fault codes related to the BCM and ensure it is functioning properly

  8. 8. Reprogram or Reset

    In some cases, reprogramming or resetting the BCM may resolve the issue

  9. 9. 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

  10. 10. Perform a Wiggle Test

    Wiggle Wiring Harness: With the vehicle running and the code present, gently wiggle the wiring harness connected to the left rear door while monitoring the code. If the code clears or changes, it may indicate a wiring issue

  11. 11. Consult Wiring Diagrams

    Refer to Service Manual: Use the vehicle's service manual to consult wiring diagrams for the door ajar circuit. This can help identify any other components that may be involved in the circuit

  12. 12. Replace Faulty Components

    Switch Replacement: If the door ajar switch is found to be faulty, replace it

  13. 13. Repair Wiring

    If any damaged wiring is found, repair or replace it as necessary

  14. 14. Clear Codes and Test Drive

    Clear Codes: After making repairs, clear the trouble codes using an OBD-II scanner

  15. 15. Test Drive

    Take the vehicle for a test drive to see if the code returns

  16. 16. Seek Professional Help

    If the issue persists after following these steps, it may be best to consult a professional mechanic or technician for further diagnosis. By following these troubleshooting steps, you should be able to identify and resolve the issue related to the B1574 code