Here's the proper procedure:
1. Diagnose the problem: The first and most crucial step is to find out *why* the CEL is on. You have a few options:
* OBD-II Scanner: This is the best approach. A relatively inexpensive OBD-II scanner (available at most auto parts stores) can read the diagnostic trouble codes (DTCs) stored by the car's computer. These codes pinpoint the specific issue. You can then research the code online or in a repair manual to understand the problem.
* Auto Parts Store: Many auto parts stores will scan your car's computer for free and tell you the trouble codes.
* Mechanic: A mechanic can diagnose the problem professionally and provide a repair estimate.
2. Repair the Problem: Once you know the DTC, fix the underlying mechanical or electrical issue causing the CEL. This might involve replacing a sensor, fixing a leak, or performing more extensive repairs.
3. Clear the Code (After Repair): After the repair, you can clear the code. There are several ways to do this:
* OBD-II Scanner: Most OBD-II scanners have a function to clear diagnostic trouble codes.
* Disconnect the Battery: A less reliable method is to disconnect the negative (-) battery terminal for about 15-20 minutes. This will often clear the code, but it doesn't guarantee it will work and it will reset other things in the vehicle's computer as well. Make sure you know how to properly reconnect the battery to avoid damaging your vehicle's electrical system.
Important Note: Simply clearing the code without fixing the problem will only temporarily turn off the light. The problem will likely persist and the light will return. It's crucial to address the root cause of the CEL to ensure the safety and proper functioning of your vehicle.
