Here's what you should do:
1. Get the diagnostic trouble code (DTC): You need to know *why* the light is on. You can do this in a few ways:
* OBD-II Scanner: The cheapest and easiest way. Buy a relatively inexpensive OBD-II scanner from an auto parts store or online. Plug it into your vehicle's OBD-II port (usually under the dashboard), and it will read the DTC. This code will tell you what the problem is.
* Auto Parts Store: Many auto parts stores will read the code for free. They'll often try to sell you the part they think is causing the problem, but you're free to decline and repair it yourself or go elsewhere.
* Mechanic: A mechanic will diagnose the problem and provide a repair quote. This is the most expensive option but guarantees a professional diagnosis and repair.
2. Address the underlying problem: Once you know the DTC, you can research the likely cause. Common causes include:
* Loose gas cap: This is a frequent, easily fixed cause. Ensure your gas cap is securely tightened.
* Faulty sensor: Oxygen sensors, mass airflow sensors, etc. are common culprits and will need replacement.
* Emission system issues: Problems with the catalytic converter, exhaust system, or other emissions components can trigger the light.
* More serious mechanical issues: The light could indicate a problem with your engine, transmission, or other major systems.
3. Clear the code (after repairing the problem): *Only after you have fixed the problem that triggered the SES light* should you clear the code. Many OBD-II scanners have a "clear codes" function. After clearing the code, drive the vehicle for a short while to allow the OBD-II system to confirm the problem is resolved. If the problem is truly fixed, the light should stay off. If it comes back on, the problem wasn't resolved.
Important Considerations:
* Don't just clear the code without fixing the problem: This is a dangerous practice. You're just masking the issue, which could lead to further damage or even unsafe driving conditions.
* Ignoring the light can be costly: Small problems often become big and expensive problems if left unaddressed.
In short, the SES light is a warning sign. Don't ignore it. Get it diagnosed properly and fix the underlying issue. Only then should you consider clearing the code.
