B1304 Code Meaning, Symptoms, Causes and How to Fix

The B1304 code signifies a problem with the accessory delay relay in a vehicle. This relay is responsible for controlling functions like door locks, power windows, and the roof opening panel.

Symptoms of this code may include illuminated engine lights or service engine soon warnings.

Potential causes for the B1304 code include a faulty relay, wiring issues, or a defective Smart Junction Box.

To resolve this issue, it is recommended to seek assistance from a professional who can accurately diagnose the problem and provide a cost estimate for the necessary repairs.

What does it mean

The B1304 code refers to a problem with the accessory delay relay in your car's electrical system. This relay powers the door lock switches, power windows, and roof opening panel.

Signs of a faulty Smart Junction Box (SJB) include an illuminated engine light.

Regularly inspect and maintain the SJB and relay to prevent future issues.

what are the symptoms

The symptoms of the B1304 code may include a lit engine light or a service engine soon warning light.

To diagnose DTC B1304, you can follow these steps:

1. Use a scan tool to retrieve the code and any related codes stored in the vehicle's computer system.
2. Inspect the accessory delay relay for any signs of damage or malfunction.
3. Check the wiring harness and connectors associated with the accessory delay relay for any open circuits, shorts, or poor electrical connections.

Some common mistakes to avoid when diagnosing DTC B1304 are:

1. Not thoroughly inspecting the accessory delay relay and its components.
2. Forgetting to check the wiring harness and connectors for potential issues.
3. Ignoring other possible causes for the code, such as a faulty Smart Junction Box (SJB).

Whate are the causes

Possible causes of the B1304 code include:

1. Faulty accessory delay relay: A relay that is not working correctly can trigger the code. This relay is responsible for supplying power to various components like door lock switches, power windows, and roof opening panels.
2. Open or shorted harness: A problem with the wiring harness connected to the accessory delay relay can cause the code to appear. This may happen due to damage to the harness or a loose connection.
3. Poor electrical connection in the relay circuit: If there is a faulty connection within the relay circuit, it can set off the B1304 code. This can occur because of issues like corrosion, bent pins, or other electrical problems.

To resolve the B1304 code, you can take the following steps:

• Check the accessory delay relay for any faults and replace it if necessary.
• Inspect the wiring harness and connectors for any damage or loose connections.
• Look for any broken, bent, pushed out, or corroded connector pins.

To prevent the DTC B1304 from happening again, it is important to regularly maintain and inspect the relay, harness, and connectors. Additionally, addressing any electrical problems promptly can help avoid the code from reappearing.

What Tools are Needed to diagnose

To diagnose the B1304 code, you will need a few tools. These tools are essential for identifying and fixing the problems related to the code. Here are the tools you'll need:

1. Diagnostic scanner: This tool retrieves the trouble codes stored in the vehicle's computer system. It gives you information about the specific issue that triggered the B1304 code.
2. Multimeter: The multimeter measures voltage, resistance, and continuity in the electrical circuits connected to the accessory delay relay and the Smart Junction Box (SJB). It helps you find any open circuits, short circuits, or faulty components.
3. Wiring diagram: This diagram shows the electrical connections and components involved in the accessory delay relay circuit. It helps you trace the wiring, locate connectors, and understand the circuitry to find any potential problems.

How to fix Step by Step

Step 1: Check the possible causes listed, such as a faulty accessory delay relay, an open or shorted harness, a poor electrical connection in the relay circuit, or a faulty Smart Junction Box (SJB).

Step 2: Visually inspect the wiring harness and connectors for any damage. Look for broken, bent, pushed out, or corroded connector pins.

Step 3: If necessary, replace the faulty accessory delay relay or repair any damaged components.

Step 4: It is recommended to consult the Factory Service Manuals for more detailed information on how to fix the B1304 code.

Step 5: If needed, have the code diagnosed by a professional at a repair shop.

Step 6: This step-by-step guide will help troubleshoot and fix the B1304 code efficiently.

What are the Common Diagnosis Mistakes

Common Diagnosis Mistakes to Avoid for DTC B1304

One common mistake when diagnosing the B1304 code is not properly checking the wiring harness and connectors for damage or corrosion. This mistake can cause the actual cause of the code to be missed, resulting in wasted time on unnecessary repairs.

To diagnose DTC B1304 accurately, it is important to avoid the following common diagnosis mistakes:

1. Focusing only on the accessory delay relay: While the relay could be a potential cause of the code, it is crucial to inspect the entire circuit, including the wiring harness and connectors, to ensure there are no issues.
2. Neglecting to check for other potential causes: It is essential to consider other possible causes, such as a faulty Smart Junction Box (SJB) or poor electrical connections. Ignoring these possibilities can lead to misdiagnosis.
3. Relying solely on visual inspection: Although visual inspection is important, it may not always uncover hidden issues. Utilizing diagnostic tools and conducting electrical tests can provide a more accurate diagnosis.

What is the Repair Cost

The repair cost for resolving the B1304 code varies depending on factors like location, vehicle make and model, engine type, and labor rates.

Luxury cars typically have higher repair costs.

Parts availability and additional repairs needed can also affect the total cost.

A professional diagnosis is recommended for an accurate repair cost.

Can I drive safely with this code?

Driving with the B1304 code, indicating a faulty accessory delay relay, can compromise vehicle safety. This relay controls important functions like door locks and power windows. It is recommended to avoid driving until the issue is resolved.

Specialized tools and a professional technician are needed for accurate diagnosis and repair.

Conclusion

In conclusion, the B1304 code indicates a problem with the accessory delay relay in a vehicle. Symptoms may include the illumination of warning lights. Possible causes include a faulty relay or electrical connections.

To diagnose and fix the issue, it is recommended to visually inspect the wiring harness and connectors and check for damaged components. The cost of repair can vary depending on various factors.

It is advisable to consult a professional for an accurate diagnosis and cost estimate.