Here's what you should do:
1. Get the diagnostic trouble code (DTC): You need to know *why* the light is on. You can do this in a few ways:
* OBD-II scanner: This is the best option. You can buy a relatively inexpensive code reader at most auto parts stores. Plug it into the OBD-II port (usually under the dashboard) and it will read the trouble code(s). This will give you a specific indication of the problem.
* Auto parts store: Many auto parts stores will read the code for free. Just be aware they may try to sell you parts or service.
2. Address the problem: Once you know the DTC, you can research it online (many resources are available) or consult a repair manual. This will help you understand the issue and determine the necessary repairs. This might involve replacing a sensor, fixing a leak, or more extensive work.
3. Clear the code (after repair): *Only after you've fixed the problem* should you clear the code. Many OBD-II scanners have this function. Sometimes disconnecting the battery for a short time (30 minutes) will also clear it, but this isn't as reliable. After clearing the code, drive the car for a while to allow the system to re-check for errors. If the light comes back on, the problem wasn't fully resolved.
In short: Don't just reset the light. Find out what's causing it and fix that first. Ignoring the check engine light can lead to significant engine damage and costly repairs later on.
