Here's the proper approach:
1. Diagnose the problem: The first and most important step is to find out *why* the SES light is on. You have several options:
* OBD-II Scanner: This is the best approach. Buy a relatively inexpensive OBD-II scanner (available at most auto parts stores) and plug it into the OBD-II port (usually under the dashboard). The scanner will read the diagnostic trouble codes (DTCs), which are numerical codes indicating the specific problem(s) the car has detected. This will give you a much better idea of what needs fixing.
* Auto Parts Store Scan: Many auto parts stores will scan your car's OBD-II system for free. They can tell you the code(s) and may even offer suggestions for repairs.
* Mechanic: If you're uncomfortable working on your car yourself, take it to a qualified mechanic. They have the tools and expertise to diagnose and fix the problem.
2. Fix the problem: Once you know the DTC(s), you can research the problem online or consult a repair manual to find the cause and how to fix it. This could range from something simple like a loose gas cap to a more serious issue requiring professional attention.
3. Clear the code (after fixing the problem): *Only after you've addressed the underlying issue* can you clear the code. You can usually do this with your OBD-II scanner. Many scanners have a "clear codes" or similar function. After clearing the codes, start the car and drive it for a while to allow the OBD-II system to confirm the problem has been resolved. If the light stays off, the problem is likely fixed. If it comes back on, you haven't completely solved the underlying issue.
Important: Simply disconnecting the battery will often clear the SES light, but this is not a good solution. It doesn't fix the problem, and the light will likely reappear. Always diagnose and repair the problem first.
