B1372 – Illuminated Entry Relay Circuit Open

The ODBII code B1372 indicates a malfunction in the illuminated entry relay circuit, specifically that the circuit is open, meaning there is a break or fault preventing proper operation of the illuminated entry system.

The severity of ODBII code B1372 is generally considered moderate.

Common Causes For: B1371 Illuminated Entry Relay Circuit Failure

• Faulty illuminated entry relay
• Open or damaged wiring in the circuit
• Poor ground connection
• Faulty door switch
• Malfunctioning body control module (BCM)
• Corroded connectors or terminals

Common misdiagnosis for B1372 Illuminated Entry Relay Circuit Open

• Faulty door switch
• Bad body control module (BCM)
• Wiring issues or shorts
• Defective key fob
• Malfunctioning interior lights
• Battery issues
• Faulty ignition switch
• Problems with the central locking system

Common Troubleshooting Steps

When dealing with an OBD-II code B1372, which indicates an “Illuminated Entry Relay Circuit Open,” there are several common troubleshooting steps you can follow to diagnose and potentially resolve the issue. Here’s a structured approach:

• Check the Vehicle’s Manual: Refer to the vehicle’s service manual for specific information regarding the illuminated entry relay circuit and its components.
• Visual Inspection: Inspect the wiring and connectors associated with the illuminated entry relay. Look for signs of damage, corrosion, or loose connections.
• Check the relay itself for any physical damage.
• Test the Relay: Remove the illuminated entry relay and test it using a multimeter. Check for continuity and ensure it operates correctly when powered.
• If the relay is faulty, replace it with a new one.
• Check Fuses: Inspect the fuses related to the illuminated entry system. A blown fuse can cause the circuit to open.
• Replace any blown fuses and retest the system.
• Inspect the Circuit: Use a multimeter to check for continuity in the wiring harness leading to and from the relay. Look for any breaks or shorts in the wiring.
• Check for proper voltage at the relay terminals when the vehicle is in the appropriate state (e.g., doors closed, ignition on).
• Check the Door Switches: Inspect the door switches that trigger the illuminated entry system. Ensure they are functioning correctly and not stuck in the open position.
• Test the switches for continuity when the door is opened and closed.
• Scan for Additional Codes: Use an OBD-II scanner to check for any additional trouble codes that may provide more context or indicate related issues.
• Inspect the Body Control Module (BCM): If all other components check out, the issue may lie within the Body Control Module. Check for any software updates or known issues with the BCM.
• If necessary, perform a reset or reprogram the BCM.
• Consult Technical Resources: If the problem persists, consult technical service bulletins (TSBs) or forums specific to your vehicle make and model for any known issues or fixes related to the B1372 code.
• Professional Diagnosis: If you are unable to resolve the issue after these steps, consider seeking help from a professional mechanic or automotive technician who has experience with electrical systems. By following these steps, you should be able to identify and address the cause of the B1372 code. Always ensure safety precautions are taken when working with electrical systems in vehicles.