I just bought a 2002 Mazda Millenia with 41,000 miles and it's a beautiful looking and running car. I ran it low on fuel and this morning the check engine light came on. I checked the gas cap and it seemed to be seated and would like to know if I can reset the check engine light or will it go off automatically when a problem is fixed. Will disconnecting the battery reset the check engine light?

 

Disconnecting the battery should clear the CEL. You should really invest in a code scanner that can clear as well as read codes.

 

Thanks for the response. This problem is very strange. The light comes on in the mornings when I start my car but in the afternoon it doesn't. I live in South Florida and at night my car is parked in a covered parking lot less than 50 yard from the Atlantic Ocean. I did have it connected to a code reader at a local auto parts store while the light was on and it indicated that my knock sensor is bad or that it has a loose connection. Can moisture in the air cause this problem?
The car runs great and has no loss of power.