* The trip odometer: This is usually done by holding down a button on the instrument cluster (often marked with a small triangle or a "0000"). The exact button and procedure will be in your owner's manual.
* The ECU (Engine Control Unit): This is the car's main computer that controls the engine. You generally *cannot* reset the ECU in the way you might reset a home computer. It automatically adapts to driving conditions. However, disconnecting the battery for a short period (30 minutes to an hour) will often clear any temporary faults stored in the ECU's memory. Caution: Disconnecting the battery will clear the radio presets and possibly other settings.
* A specific malfunction indicator lamp (MIL) or check engine light: This requires a diagnostic scan tool to diagnose the problem and then clear the code after the problem is fixed. You can't just reset the light without addressing the underlying issue; it will likely come back on.
To figure out what you need to reset, please specify what you're trying to achieve. For example:
* "I want to clear the trip odometer."
* "My check engine light is on."
* "The car is running poorly, and I heard disconnecting the battery might help."
Once you clarify your goal, I can provide more specific instructions. Referencing your owner's manual will also be very helpful.
