Here's the correct procedure:
1. Diagnose the Problem: The first and most important step is to find out *why* the check engine light is on. You have a few options:
* OBD-II Scanner: The best approach is to use an OBD-II scanner (available relatively cheaply at auto parts stores). This will read the diagnostic trouble codes (DTCs) stored in your vehicle's computer. These codes give you specific information about the problem.
* Auto Parts Store Scan: Many auto parts stores will scan your vehicle's codes for free. This can give you a starting point.
* Mechanic: A mechanic can diagnose the problem professionally. This is the best option if you're uncomfortable working on your car yourself.
2. Repair the Problem: Once you know the DTC(s), you can research the issue online or consult a repair manual to fix the problem. This could involve anything from replacing a sensor to more extensive repairs.
3. Clear the Code (After Repair): *Only after you've repaired the problem* can you clear the code. There are several ways to do this:
* OBD-II Scanner: Most OBD-II scanners have a function to clear trouble codes.
* Disconnect the Battery: This is a less reliable method. Disconnect the negative battery terminal for at least 15 minutes. Reconnect the battery. This *might* clear the code, but it won't solve the underlying problem, and the light will likely return. This method is not recommended.
Important Considerations:
* Ignoring the light is not recommended. Driving with a check engine light on could cause further damage to your engine or other systems, potentially leading to expensive repairs down the line.
* A simple reset won't fix the problem. The light will likely come back on until the underlying issue is addressed.
In short: Don't just reset the light. Find out what's causing it and fix it. Then, and only then, clear the code.
