Here's what you should do:
1. Get the diagnostic trouble codes (DTCs): You need to know *why* the CEL is on. You can do this in a few ways:
* OBD-II Scanner: The most reliable method is to use an OBD-II scanner (available at most auto parts stores). These scanners plug into your car's OBD-II port (usually under the dashboard) and will read the DTCs. The codes will be numerical, and you can then look up their meaning online or in a repair manual.
* Auto Parts Store: Many auto parts stores will read the codes for free.
2. Address the Problem: Once you know the DTCs, research the problem online or consult a repair manual. The problem could be anything from a loose gas cap to a more serious issue requiring professional repair. *Fix the problem before attempting to clear the code.*
3. Clear the Code (After Repair): After you've fixed the problem that triggered the CEL, you can clear the code. There are several ways to do this:
* OBD-II Scanner: Most OBD-II scanners also have a "clear codes" function. Simply connect the scanner and follow the instructions to clear the codes.
* Disconnect the Battery: This is a less reliable method, but it can sometimes work. Disconnect the negative (-) battery terminal for about 10-15 minutes. This will reset the computer, but it may not clear all codes, and you'll need to drive the car for some time (often a drive cycle) for the computer to re-learn the system.
Important Considerations:
* Ignoring the CEL is risky: Driving with a check engine light on can lead to further damage to your car and potentially unsafe driving conditions.
* Professional Help: If you're not comfortable diagnosing and repairing the problem yourself, take your car to a qualified mechanic.
In short, resetting the light is the *last* step, not the first. Focus on finding and fixing the problem causing the CEL.
