B1572 – Door Ajar LR Circuit Open

The ODBII code B1572 indicates that there is an open circuit in the left rear door ajar switch, meaning the vehicle’s system is detecting that the left rear door is not properly signaling whether it is open or closed.

The severity of ODBII code B1572 Door Ajar LR Circuit Open is moderate.

Common Causes For: B1571 Door Ajar LR Circuit Failure

• Faulty door ajar switch
• Damaged wiring or connectors
• Short circuit in the circuit
• Corroded terminals
• Faulty body control module (BCM)
• Misaligned door or latch
• Water intrusion or moisture damage

Common misdiagnosis for B1572 Door Ajar LR Circuit Open

• Faulty door latch
• 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

Common Troubleshooting Steps

The OBD-II code B1572 indicates a problem with the “Door Ajar” circuit for the left rear door (LR) of a vehicle. This code typically means that the vehicle’s computer has detected an open circuit or a fault in the door ajar switch or its associated wiring. Here are some common troubleshooting steps to diagnose and resolve the issue:

• Visual Inspection: **Check the Door Ajar Switch: Inspect the left rear door ajar switch for any visible damage or disconnection. Ensure that it is properly mounted and functioning.
• **Wiring Inspection: Look for any damaged, frayed, or corroded wires in the door harness. Pay special attention to areas where the wiring may flex or bend when the door is opened and closed.
• Test the Door Ajar Switch: **Multimeter Test: Use a multimeter to test the door ajar switch. With the door closed, the switch should be in the “off” position (closed circuit). When the door is opened, the switch should be in the “on” position (open circuit). If it does not behave as expected, the switch may need to be replaced.
• Check for Faulty Connections: **Connector Inspection: Inspect the connectors at the door and the body for corrosion, dirt, or loose connections. Clean and secure any connections that appear to be faulty.
• 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.
• Test the Circuit: **Continuity Test: Perform a continuity test on the wiring between the door ajar switch and the vehicle’s body control module (BCM). This will help identify any breaks in the wiring.
• **Voltage Test: Check for proper voltage at the door ajar switch connector when the door is opened and closed.
• Inspect the Body Control Module (BCM): **BCM Functionality: If all other components test fine, the issue may lie within the BCM itself. Check for any software updates or known issues with the BCM for your specific vehicle model.
• Clear the Code and Test Drive: 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.
• Consult a Professional: If the issue persists after following these steps, it may be best to consult a professional mechanic or technician who has experience with your specific vehicle make and model. By following these troubleshooting steps, you should be able to identify and resolve the issue related to the B1572 code.