B1305 – Accessory Delay Relay Coil Circuit Short To Ground

The ODBII 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.

The severity of ODBII code B1305 is moderate.

Common Causes For: B1304 Accessory Delay Relay Coil Circuit Short To Battery

• 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 misdiagnosis for B1305 Accessory Delay Relay Coil Circuit Short To Ground

• 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

Common Troubleshooting Steps

When dealing with OBD-II code B1305, which indicates a problem with the Accessory Delay Relay Coil Circuit Short to Ground, there are several common troubleshooting steps you can follow to diagnose and potentially resolve the issue. Here’s a structured approach:

• 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.
• 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.
• Inspect the Wiring and Connectors: **Visual Inspection: Look for damaged, frayed, or corroded wires and connectors in the accessory delay relay circuit.
• **Ground Connections: Ensure that all ground connections are secure and free of corrosion.
• 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.
• **Relay Circuit: Check the relay socket for any signs of damage or corrosion.
• 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.
• **Wiring Harness: Inspect the wiring harness for any signs of wear or damage that could lead to a short circuit.
• 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.
• 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.
• 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.
• 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.
• 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
• 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.