B1371 – Illuminated Entry Relay Circuit Failure

The ODBII code B1371 indicates a failure in the illuminated entry relay circuit, which is responsible for controlling the interior lights when the vehicle is unlocked or the doors are opened.

The severity of ODBII code B1371 is generally considered moderate.

Common Causes For: B1370 Ignition Tach Circuit Short To Ground

• Faulty illuminated entry relay
• Wiring issues (shorts or open circuits)
• Corroded or damaged connectors
• Malfunctioning door switches
• Faulty body control module (BCM)
• Blown fuses
• Grounding issues

Common misdiagnosis for B1371 Illuminated Entry Relay Circuit Failure

• Faulty door switches
• Malfunctioning body control module (BCM)
• Wiring issues or shorts in the circuit
• Defective interior lights
• Battery or power supply problems
• Faulty key fob or remote entry system
• Issues with the ignition switch

Common Troubleshooting Steps

When dealing with an OBD-II code B1371, which indicates an “Illuminated Entry Relay Circuit Failure,” 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 energized.
• 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 fail.
• Replace any blown fuses and retest the system.
• Inspect the Door Switches: Check the door switches (usually located in the door frame) to ensure they are functioning properly. A faulty switch can prevent the relay from activating.
• 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.
• Check the Body Control Module (BCM): The BCM often controls the illuminated entry system. Inspect the BCM for any faults or issues.
• If necessary, perform a reset or reprogram the BCM according to the manufacturer’s specifications.
• Inspect Ground Connections: Ensure that all ground connections related to the illuminated entry system are secure and free of corrosion.
• Test the Circuit: Use a multimeter to test the voltage and ground at the relay and switches. Ensure that the circuit is receiving the correct voltage when the doors are opened.
• Consult Technical Service Bulletins (TSBs): Check for any TSBs related to the illuminated entry system for your specific vehicle make and model. There may be known issues or recalls that could apply.1
• Professional Diagnosis: If the issue persists after performing these steps, consider seeking help from a professional mechanic or automotive technician who can perform more advanced diagnostics.Conclusion By following these troubleshooting steps, you should be able to identify the cause of the B1371 code and take appropriate action to resolve the issue. Always ensure safety precautions are taken when working on vehicle electrical systems.