B1574 – Door Ajar LR Circuit Short To Ground

The ODBII 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.

The severity of ODBII code B1574 Door Ajar LR Circuit Short To Ground is moderate.

Common Causes For: B1573 Door Ajar LR Circuit Short To Battery

• 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 misdiagnosis for B1574 Door Ajar LR Circuit Short To Ground

• 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

Common Troubleshooting Steps

When dealing with an OBD-II code B1574, which indicates a “Door Ajar LR Circuit Short To Ground,” it typically points to an issue with the left rear door’s ajar switch or its associated wiring. Here are some common troubleshooting steps to help diagnose and resolve the issue:

• 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.
• **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.
• 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.
• **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).
• 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.
• **Test Ground Circuit: Use a multimeter to check the ground circuit for continuity and ensure it is not shorted to the vehicle’s chassis.
• 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.
• **Reprogram or Reset: In some cases, reprogramming or resetting the BCM may resolve the issue.
• 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.
• 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.
• 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.
• Replace Faulty Components: **Switch Replacement: If the door ajar switch is found to be faulty, replace it.
• **Repair Wiring: If any damaged wiring is found, repair or replace it as necessary.
• Clear Codes and Test Drive: **Clear Codes: After making repairs, clear the trouble codes using an OBD-II scanner.
• **Test Drive: Take the vehicle for a test drive to see if the code returns.
• 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.