Why does the service engine light come on?
Why does the service engine light come on? The service engine light is connected to your emissions control system. This is why, when the light comes on, you'll notice that your fuel efficiency will go down. The system has a sensor attached to the fuel cap and will trigger the service engine light whenever the fuel cap isn't closed tightly. Check if the fuel cap is closed all the way. Where is the service light on a car? The Service (or Service Engine) light is a warning light that is connected to the engine control unit (ECU) of a vehicle....