My "Service Engine Soon" light came on yesterday. Everything is running fine. I'm thinking a sensor was tripped. Anyone know a quick way to reset this. A possibility is that my gas cap wasn't screwed on right. Is there a button for a reset for that. The only other thing I think it can be is the 02 sensor. Any help is appreciated, trying to avoid a trip to the dealership. Thanks!

 

The MIL seldom comes on for absolutely no reason. Just because your car seems to be running fine doesn't mean that there's not a malfunction. As you stated, it could very well be an O2 sensor and you might not notice any difference in how it runs.

There is no button to push to make it go away. You can go to some auto parts stores and they will read the code for free (Auto Zone) and can reset it if you want. You can buy your own OBD II tool and see what the code is and reset it yourself. I recently got this one for $50 that's adequate to read and reset codes:
ActronŽ