Transmission Control Module (TCM) faults are not unknown on these early Mazda 3s. Symptoms usually involve erratic shifting, a failure to select gear at all and having the car go into limp-home mode.

If you're a control freak, late-model electronic transmissions are just what you need to modernize your classic car, and if you decide to go that route, a transmission control module is a must-have.

A faulty transmission speed sensor can lead to numerous issues, including things like rough shifts, cruise control ...