1995 Cadillac DeVille Owner's Manual - Page 153

Malfunction IndicatorLamp (Service Engine Soon Light) ... . . .. ... . ,.. NOTICE: If you keep tlri\ing your \chicle w i t h this light on, after a while the emission controls won't work a s well, your fuel economy won't be as good and your engine may not run as smoothly. This could lead to costly repairs not coyerecl by your warranty.