WOMS
B code body Medium severity

B1305 Accessory Delay Relay Coil Circuit Short To Ground

The OBD2 code B1305 indicates a short circuit in the accessory delay relay coil circuit, which means that the circuit is improperly connected to ground, potentially causing issues with the operation of the accessory...

Definition

The OBD2 code B1305 indicates a short circuit in the accessory delay relay coil circuit, which means that the circuit is improperly connected to ground, potentially causing issues with the operation of the accessory delay feature

Common causes

  • Shorted wiring or connectors in the accessory delay relay circuit
  • Faulty accessory delay relay
  • Damaged or corroded ground connections
  • Malfunctioning body control module (BCM)
  • Incorrectly installed aftermarket accessories
  • Water intrusion or moisture in electrical connectors

Common misdiagnoses

  • Faulty accessory delay relay
  • Shorted wiring harness
  • Defective body control module (BCM)
  • Malfunctioning ignition switch
  • Battery or charging system issues
  • Faulty fuses or connections
  • Incorrectly installed aftermarket accessories

Troubleshooting steps

  1. 1. Understand the Code

    B1305 typically refers to a malfunction in the accessory delay relay circuit, which is responsible for controlling power to accessories after the ignition is turned off

  2. 2. Check for Additional Codes

    Use an OBD-II scanner to check for any other related trouble codes. This can provide more context and help identify if there are multiple issues

  3. 3. Inspect the Wiring and Connectors

    Visual Inspection: Look for damaged, frayed, or corroded wires and connectors in the accessory delay relay circuit

  4. 4. Ground Connections

    Ensure that all ground connections are secure and free of corrosion

  5. 5. Test the Accessory Delay Relay

    Relay Functionality: Remove the relay and test it using a multimeter to ensure it operates correctly. You can also swap it with a known good relay to see if the problem persists

  6. 6. Relay Circuit

    Check the relay socket for any signs of damage or corrosion

  7. 7. Check for Short Circuits

    Continuity Test: Use a multimeter to check for continuity in the circuit. Look for any shorts to ground that may be causing the code

  8. 8. Wiring Harness

    Inspect the wiring harness for any signs of wear or damage that could lead to a short circuit

  9. 9. Inspect the Accessory Components

    Check any accessories that are powered by the delay relay (e.g., power windows, radio) for faults that could be causing excessive current draw or shorts

  10. 10. Test the Power Supply

    Ensure that the relay is receiving the correct voltage from the power source. Use a multimeter to check the voltage at the relay terminals

  11. 11. Check the Body Control Module (BCM)

    If all other components check out, the issue may lie within the BCM. Inspect for any faults or software issues that could be affecting the relay operation

  12. 12. Clear the Code and Test Drive

    After performing repairs or adjustments, clear the code using the OBD-II scanner and take the vehicle for a test drive to see if the code returns

  13. 13. Consult Repair Manuals or Technical Service Bulletins (TSBs)

    If the issue persists, consult the vehicle’s repair manual or look for TSBs related to the B1305 code for specific guidance related to your vehicle make and model.1

  14. 14. Seek Professional Help

    If you are unable to resolve the issue after these steps, it may be best to consult a professional mechanic or technician who has experience with your specific vehicle. By following these steps, you should be able to diagnose and potentially fix the issue related to the B1305 code. Always ensure safety precautions are taken when working on vehicle electrical systems