What you likely mean is resetting one of these specific computer systems. The method depends on what you're trying to achieve:
* Resetting the Engine Control Module (ECM): This often helps with minor glitches in the engine's performance. The most common method is disconnecting the negative terminal of the battery for about 30-60 minutes. This allows the computer's memory to clear. Reconnect the battery and let the car run for a while to allow the computer to relearn your driving habits. *Caution:* Be sure to disconnect the negative terminal first (to avoid short circuits). Also, this will erase any personalized settings (like radio presets).
* Resetting the Transmission Control Module (TCM): Similar to the ECM, disconnecting the battery negative terminal for an extended period (30-60 minutes) is the typical approach. This is often done to address minor transmission issues, but it's less common than ECM resets.
* Other Modules: Other modules like the climate control system might have their own reset procedures (often involving holding down certain buttons on the control panel). Consult your owner's manual for specific instructions related to these systems.
Important Note: If you are experiencing major problems with your car (like a persistent check engine light, poor performance, or transmission problems), simply resetting the computer may not fix the underlying issue. It's best to diagnose the problem with a professional mechanic or OBD-II scanner before resorting to resets. Ignoring a legitimate mechanical problem can lead to further and more costly damage.
