The TCM, or Transmission Control Module, is a key piece of any automatic transmission. Here's how it works in your car and how to fix it.

Comparing features of the latest stand-alone automatic transmission control modules. Which one will work best for your transmission? Jeff Smith breaks it down.

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.