B1300 OBD-II Trouble Code: Power Door Lock Circuit Failure

diagnostic check engine light

B1300 code definition

The B1300 trouble code detects an error with the power door lock circuit.

What the B1300 code means

The B1300 code is a generic OBD-II trouble code that suggests a circuit error with the power door lock. The power door lock system is a basic system that controls the locks for all the doors, as well as the trunk, so failure to this system can compromise all of the vehicle’s locks at once. When the body control module or powertrain control module (PCM) detects an error with the power door lock circuit, then the B1300 trouble code will likely be stored.

What causes the B1300 code?

There are three common causes for the B1300 trouble code:

What are the symptoms of the B1300 code?

When the B1300 trouble code is detected, there will likely be problems with the power door lock system. This may mean that the power locks will only work intermittently, or it may mean that they fail to work altogether, and the vehicle will be incapable of locking the doors.

How does a mechanic diagnose the B1300 code?

The B1300 code will be addressed using a standard OBD-II trouble code scanner. This scanner can be hooked up to the vehicle so that the mechanic can view the freeze frame data and assess the code, and also check for any additional trouble codes that are present. If the mechanic finds that multiple codes are present, then they will be addressed in the order in which they appear. The mechanic will likely then reset the code, restart the vehicle, and check to see if the code remains detected. If the mechanic has already verified that the power door lock issue is present, then this step may be unnecessary. If the code is not detected after reset, then it was likely erroneously triggered.

If the code remains detected, then the mechanic will start by visually inspecting the electrical components in the power door lock system. All damaged wires, connectors, and fuses will need to be replaced. The power door lock relay and actuator can then be inspected, which can be done visually, or often by sound when the power door lock button is pressed.

After any replacement, the codes will need to be reset, the vehicle restarted, and the code again checked for. This will let the mechanic know that the issue is resolved.

Common mistakes when diagnosing the B1300 code

The most frequently made mistake when diagnosing this code comes from a failure to properly follow the OBD-II trouble code diagnosis protocol. It’s important for mechanics to follow the protocol, even with relatively simple diagnoses, as it helps guarantee a thorough inspection with accurate repairs.

Often power door lock actuators and relays are falsely replaced, when the issue is electrical.

How serious is the B1300 code?

A vehicle with the B1300 trouble code will usually have problems with the power door lock system. The power door locks are a key security feature, so the vehicle should be inspected as soon as the code is detected.

What repairs can fix the B1300 code?

Repairs for the B1300 trouble code include:

Additional comments for consideration regarding the B1300 code

While the B1300 trouble code normally signals a power door lock circuit malfunction, it has a different definition for a few makes and models. The definition of the code for the vehicle that it appears on should always be verified before diagnosis.

Need help with a B1300 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

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