Here's why it could be on despite proper servicing:
* Sensor Issues: Many different sensors monitor engine performance (oxygen sensor, mass airflow sensor, crankshaft position sensor, etc.). A failing sensor will trigger the light even if other parts of the engine are working correctly. These are common culprits.
* Emissions System Problems: Issues with the catalytic converter, evaporative emission system (EVAP), or other emission control components can activate the SES light.
* Other Engine Problems: A less common but still possible reason is a problem within the engine itself – a minor leak, a failing component, or something more serious.
* Loose Gas Cap: A surprisingly frequent cause is a loose or faulty gas cap. A leak in the fuel system will trigger the light.
* OBD-II System Malfunction: While rare, a fault within the OBD-II system itself could cause the light to illuminate incorrectly.
What you should do:
1. Get the Code Read: The most important step is to get the diagnostic trouble code (DTC) read. This code will pinpoint the specific problem the computer detected. You can:
* Use an OBD-II scanner: These are relatively inexpensive and readily available at auto parts stores.
* Take it to an auto parts store: Many stores offer free code reading services.
* Take it to a mechanic: A mechanic will read the code and likely have a better understanding of what the code means for your specific vehicle.
2. Address the Problem: Once you know the code, you can research the issue online or consult a mechanic to determine the best course of action. Some problems are simple fixes, while others may require more extensive repairs.
Ignoring the light could lead to further damage or even dangerous driving conditions. It's best to address the issue promptly.
