B1304 – Accessory Delay Relay Coil Circuit Short To Battery

The ODBII code B1304 indicates a malfunction in the accessory delay relay coil circuit, specifically a short circuit to the battery, which can prevent the relay from functioning properly.

The severity of ODBII code B1304 is moderate.

Common Causes For: B1303 Accessory Delay Relay Coil Circuit Open

• Shorted wiring or connectors in the accessory delay relay circuit.
• Faulty accessory delay relay.
• Corroded or damaged electrical connections.
• Malfunctioning body control module (BCM).
• Incorrectly installed aftermarket accessories.
• Grounding issues in the circuit.

Common misdiagnosis for B1304 Accessory Delay Relay Coil Circuit Short To Battery

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

Common Troubleshooting Steps

The OBD-II code B1304 refers to a problem with the accessory delay relay coil circuit, specifically indicating a short to battery. This code is often associated with issues in the vehicle’s electrical system, particularly in the accessory delay relay circuit. Here are some common troubleshooting steps to diagnose and resolve this issue:

• Check the Vehicle’s Battery and Charging System: **Inspect the Battery:** Ensure the battery is in good condition, fully charged, and terminals are clean and tight.
• **Test the Charging System:** Use a multimeter to check the voltage output of the alternator while the engine is running. It should typically be between 13.5 to 14.5 volts.
• Inspect the Accessory Delay Relay: **Locate the Relay:** Find the accessory delay relay in the fuse box or relay panel (refer to the vehicle’s service manual for the exact location).
• **Check for Damage:** Inspect the relay for any signs of damage, corrosion, or burnt contacts.
• **Test the Relay:** Swap the relay with a similar one (if available) to see if the problem persists.
• Examine Wiring and Connectors: **Visual Inspection:** Look for damaged, frayed, or corroded wiring in the accessory delay relay circuit.
• **Check Connectors:** Ensure all connectors are secure and free of corrosion. Pay special attention to ground connections.
• **Use a Multimeter:** Test the continuity of the wiring from the relay to the battery and other components in the circuit.
• Check for Short Circuits: **Inspect for Shorts:** Use a multimeter to check for shorts to ground or battery voltage in the accessory delay relay circuit.
• **Isolate the Circuit:** Disconnect components one at a time to identify if a specific part is causing the short.
• Scan for Additional Codes: **Use an OBD-II Scanner:** Check for any other trouble codes that may provide additional context or indicate related issues.
• **Clear Codes:** After repairs, clear the codes and see if the B1304 code returns.
• Inspect Related Components: **Check Fuses:** Inspect any fuses related to the accessory delay relay circuit for continuity and replace if necessary.
• **Look for Other Malfunctions:** Sometimes, other components like the body control module (BCM) or ignition switch can cause issues in the circuit.
• Consult the Service Manual: **Refer to Wiring Diagrams:** Use the vehicle’s service manual to understand the circuit layout and identify any specific components that may be involved.
• Professional Diagnosis: If the issue persists after performing the above steps, consider seeking help from a professional mechanic or automotive technician who can perform more advanced diagnostics. By following these troubleshooting steps, you should be able to identify and resolve the issue related to the B1304 code. Always ensure safety precautions are taken when working with the vehicle’s electrical system.