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P0631 OBD-II Trouble Code: VIN Not Programmed or Incompatible – TCM

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P0631 code definition

A P0631 refers to the transmission control module's failure to recognize the vehicle's identification number.

What the P0631 code means

The P0631 indicates that your vehicle's transmission control module has been unable to register its own identification number. Although this may be the result of faulty components, it's most often the cause of an improperly programmed command module.

What causes the P0631 code?

If the vehicle's Powertrain Control Module (PCM) has been replaced, the connected modules will need to be reprogrammed accordingly. If this does not occur, it may result in a debilitating P0631 instance. If the PCM has been damaged or left unpowered for a long enough time, it may lose its memory and require programming. PCM and transmission control module-related wiring may also be a cause for this issue.

What are the symptoms of the P0631 code?

A P0631 trouble code will typically result in the vehicle's inability to start. Although it is a relatively simple and rare malfunction, the vehicle will be completely disabled until such a time where the problem has been solved. In any case, the vehicle computer will store a P0631 OBD-II code for diagnostic purposes and the dashboard light will be illuminated.

How does a mechanic diagnose the P0631 code?

A mechanic may first diagnose the trouble code by hooking up an OBD-II code reader to the vehicle's onboard computer. All of the system-related wiring and connectors should be inspected thoroughly for signs of damage or corrosion.

Common mistakes when diagnosing the P0631 code

If any modules require replacing in order to solve a P0631 code, they may require reprogramming after the fact. Besides that, due to the relative rarity and simplicity of the P0631, there have been few reported instances of misdiagnosing the issue.

How serious is the P0631 code?

Although a P0631 is usually simple to solve, the problem will likely result in the vehicle's failure to start.

What repairs can fix the P0631 code?

The transmission control module and PCM will need to be reprogrammed by a mechanic in order to solve this issue. All wiring relating to the transmission control module should be checked for signs of trouble and react accordingly. After following through with any necessary repairs, make sure to give the vehicle a test drive directly afterwards to see if the trouble code returns.

Additional comments for consideration regarding the P0631 code

The P0631 is noted for its rarity. Mechanics report few cases of this issue. The P0631 is usually avoided entirely by properly reprogramming modules in the first place.

Need help with a P0631 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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