1996 Cadillac DeVille Owner's Manual - Page 132

Malfunction IndicatorLamp (Service Engine Soon Light) Your Cadillac is equipped with a computer which monitors operationof the fuel, ignition and emission control systems. NOTICE: - SERVICE ENGINE SOON If you keep driving your vehicle with this light on, aftera while, your emission controls may not work as well, your fuel economy may not be as good and your engine may notrun as smoothly. This could lead to costly repairs that may not be covered by your warranty. This systemis called OBDI1 (On-Board Diagnostics-Second Generation) and is intended to assure that emissions are at acceptable levels for the lifeof the vehicle, helping to produce a cleaner environment. (In Canada, OBD is replaced by I1 Enhanced Diagnostics.) The SERVICE ENGINE SOON light comeson to indicate that there is a problem and be service is required. Malfunctions often will indicated by the system before any problem is apparent, which may prevent more serious damage to your vehicle. This system is also designed to assist your service technician in correctly diagnosing any malfunction. This light should come on, as a checkto show you it is working, when the ignition is on and the engine is not running. If the light doesn't come on, have it repaired. This light willalso come on during a malfunction in one of two ways: Light FIashing -- A misfire conditionhas been and detected. A misfire increases vehicle emissions may damage theemission control system on your vehicle. Dealer or qualified service center diagnosis and serviceis required. Light On Steady -- An emission control system malfunction has been detected on your vehicle. Dealer or qualified service center diagnosis and service may be required. 2-69