B1504 – Lamp Turn Signal Right Circuit Open

The ODBII code B1504 indicates that there is an open circuit in the right turn signal lamp circuit, meaning the system is not detecting the expected electrical connection or signal from the right turn signal.

The severity of ODBII code B1504 is moderate.

Common Causes For: B1503 Lamp Turn Signal Right Circuit Failure

• Open circuit in the wiring
• Faulty turn signal bulb
• Bad turn signal socket
• Corroded or loose connections
• Faulty turn signal switch
• Defective body control module (BCM)

Common misdiagnosis for B1504 Lamp Turn Signal Right Circuit Open

• Faulty turn signal switch
• Defective body control module (BCM)
• Broken or damaged wiring harness
• Malfunctioning relay
• Burnt-out bulb
• Poor ground connection
• Faulty fuse
• Incorrectly installed aftermarket lighting
• Corroded connectors
• Issues with the instrument cluster

Common Troubleshooting Steps

The OBD-II code B1504 indicates a problem with the right turn signal circuit, specifically that there is an open circuit. Here are some common troubleshooting steps to diagnose and resolve this issue:

• Visual Inspection:
• Check the right turn signal bulb to ensure it is not burned out. Replace it if necessary.
• Inspect the bulb socket for corrosion or damage.
• Examine the wiring harness and connectors leading to the right turn signal for any signs of fraying, breaks, or corrosion.
• Check Fuses:
• Locate the fuse box and check the fuse associated with the turn signal circuit. Replace any blown fuses.
• Test the Bulb Socket:
• Use a multimeter to check for continuity in the bulb socket. If there is no continuity, the socket may need to be replaced.
• Inspect Wiring:
• Follow the wiring from the turn signal back to the main harness. Look for any signs of damage, such as cuts, abrasions, or loose connections.
• Pay special attention to areas where the wiring may be exposed to heat or moving parts.
• Check Ground Connections:
• Ensure that the ground connection for the right turn signal is secure and free of corrosion. A poor ground can cause circuit issues.
• Test the Turn Signal Switch:
• The turn signal switch itself may be faulty. Test the switch for proper operation using a multimeter. If it is not functioning correctly, it may need to be replaced.
• Scan for Additional Codes:
• Use an OBD-II scanner to check for any additional trouble codes that may provide more context for the issue.
• Perform a Circuit Test:
• With the turn signal activated, use a multimeter to check for voltage at the turn signal connector. If there is no voltage, trace the circuit back to find where the open circuit is occurring.
• Consult Wiring Diagrams:
• Refer to the vehicle’s wiring diagrams to understand the circuit layout and identify any potential problem areas.
• Professional Diagnosis:
• If the issue persists after performing these steps, consider seeking help from a professional mechanic who can perform more advanced diagnostics. By following these steps, you should be able to identify and resolve the issue causing the B1504 code.