Here's the proper procedure:
1. Diagnose the Problem: The first and most crucial step is to find out *why* the light is on. You have several options:
* OBD-II Scanner: This is the best approach. A relatively inexpensive OBD-II scanner (available at most auto parts stores) can be plugged into your car's OBD-II port (usually under the dashboard) to retrieve diagnostic trouble codes (DTCs). These codes provide clues about the specific problem. You can then search online for the meaning of the codes.
* Auto Parts Store: Many auto parts stores will scan your car's codes for free. They can then advise you on potential solutions or repairs.
* Mechanic: A qualified mechanic can accurately diagnose the problem and perform the necessary repairs. This is often the best option, especially if you're not comfortable working on cars yourself.
2. Repair the Problem: Once you know the cause of the light, fix the issue. This might involve replacing a faulty sensor, fixing a leak, or addressing a more significant mechanical problem.
3. Clear the Code (After Repair): *Only after you've repaired the problem* should you attempt to clear the code. Many OBD-II scanners have a "clear codes" function. Some newer scanners will automatically clear the code after successful completion of a repair procedure, but not all.
* Disconnecting the Battery: A less reliable method is to disconnect the negative (-) terminal of your car battery for about 15-20 minutes. This can sometimes clear the code, but it's not guaranteed and may not work for all problems.
Important Note: Simply clearing the code without fixing the underlying problem will only temporarily turn off the light. The problem will likely persist, and the light will reappear, potentially leading to further damage. Always address the root cause of the check engine light.
