Illumination of the Check Engine Light can be caused by a loose or worn gas cap.
2003 Cadillac DeVille Problem Reports
Most Reported 2003 Cadillac DeVille Problem Reports
The steering wheel position sensor may fail, resulting in the service stability message being displayed.
Water may be drawn into the secondary air injection (AIR) pump causing the pump to fail and the Check Engine Light to illuminate. Our technicians tell us there is a kit available from General Motors to relocate the air intake for the pump which should prevent future damage from water intrusion.
Acid may leak from the battery at the cable connections, resulting in corrosion on the battery cable ends and in the battery tray. A Leaking battery should be replaced and the cables thoroughly cleaned or replaced if necessary.