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.

To convince the transmission control module that a working automatic was still installed and clear the fourteen-odd diagnostic codes, [Dean] put together a block of eight common automotive relays.

The fix: to address the poor shifting issue, GM has instructed technicians to replace the Chevy Silverado 1500’s transmission control module. This procedure includes the related software ...