How are transmission control module issues diagnosed?
When the TCM is suspected of failure, the technician will test each of its pins by comparing the current readings to what they’re supposed to be. With so many possible failure symptoms, reference materials will guide the technician through the process of locating the pins and wires that correspond to the issue at hand.
How is the transmission control module replaced?
Replacing the TCM is normally easy since it has to first be accessed for diagnostics. The hardest part can be finding the TCM. In most vehicles, it’s in the engine bay, but some manufacturers place it inside the car. It can even be located in the trunk.
Once it’s found and confirmed as the problem, the module can be unplugged and removed, and the replacement can be connected to the vehicle.
RepairPal recommendations for transmission control module issues
When dealing with electronic systems, especially if the issue pertains to a control module, we recommend thorough diagnostics before replacing parts. It would be very easy to spend hundreds of dollars on new components before realizing the issue is caused by something else.
What to look out for when dealing with transmission control module issues
If the battery is installed or jump-started incorrectly, the TCM can be destroyed, along with other sensors and wiring.
Can I replace the transmission control module myself?
Replacing the TCM on most vehicles is fairly easy, but finding it can be difficult. Plus, the new part will need to be calibrated, so this repair is usually best left to a professional.