The Engine Control Module, or ECM, directly controls the engine. Still, it can’t do that properly without the Transmission Control Module or TCM and PCM, which work together and exchange information.

Consumer Reports explains what the check engine light means and what to do when you see it: how to tell if your car has a loose gas cap—or a serious engine problem.

During their final years, a handful of automakers experimented with computer control of the humble carb, trying to squeeze out every last bit of efficiency and reduce pollution as much as possible.

And, should it tickle your fancy, BulletProof Diesel also offers a billet water pump and upgraded fuel injection control module (FICM) for the 6.0L Power Stroke.