Here's the proper procedure:
1. Diagnose the problem: The first step is to find out *why* the CEL is on. You can do this in a few ways:
* OBD-II Scanner: The most reliable method is using an OBD-II scanner (available at most auto parts stores). Plug it into the OBD-II port (usually located under the dashboard) and it will read the diagnostic trouble codes (DTCs). These codes provide clues about the issue. You can then look up the codes online to get more information.
* Auto Parts Store: Many auto parts stores will read the codes for free. They can often give you an initial assessment of the problem.
2. Repair the Problem: Once you know the DTCs, you (or a mechanic) can repair the identified issue. This could be anything from a loose gas cap to a more serious engine problem.
3. Clear the Code (After Repair): *Only after you've repaired the problem* should you clear the CEL. You can do this with the same OBD-II scanner you used for diagnosis. Many scanners have a "clear codes" or similar function. Some basic scanners may not have this capability, so check the manual that comes with the scanner.
Important Note: Simply disconnecting the battery to reset the light is a temporary fix. The light will come back on if the problem isn't resolved. This method also risks losing important settings in your car's computer. Do not rely on this method.
In short, fixing the underlying problem is crucial. Ignoring the Check Engine Light is not recommended and could cause serious and costly damage to your vehicle. Always diagnose the issue before attempting to clear the light.
