Here's the proper procedure:
1. Diagnose the problem: The most important step. You *must* find out why the light is on. You can do this in a few ways:
* OBD-II Scanner: This is the best option. A relatively inexpensive OBD-II scanner (available at most auto parts stores) can read the diagnostic trouble codes (DTCs) stored in your car's computer. These codes will tell you exactly what the problem is. Then you can research the code online or consult a repair manual.
* Auto Parts Store: Many auto parts stores will read the codes for free. They can then help you determine the likely cause and what parts you need.
* Mechanic: A qualified mechanic will be able to diagnose the issue properly and perform the necessary repairs.
2. Repair the problem: Once you know the cause, fix it! This might involve replacing a sensor, fixing a leak, or addressing a more significant mechanical issue.
3. Clear the code (after repair): *Only* after you've addressed the problem causing the light to illuminate, you can clear the code. There are several ways to do this:
* OBD-II Scanner: Most scanners have a function to clear diagnostic trouble codes.
* Disconnect the battery: Disconnect the negative (-) battery terminal for about 10-15 minutes. This will often clear the code, but it's not guaranteed and may not work for all codes. *Note:* This will reset other settings in your car, like radio presets.
* Mechanic: Your mechanic will clear the code as part of the repair service.
Important Considerations:
* Ignoring the light is dangerous: The check engine light is there to alert you to potential problems. Ignoring it could lead to more serious (and expensive) damage to your car.
* Resetting without repair is pointless: The light will come back on until the underlying problem is fixed.
In short: Don't focus on resetting the light. Focus on *fixing the problem* that caused the light to illuminate in the first place. The light reset is the last step, not the first.
