Black plate (63,1)Cadillac STS Owner Manual - 2011This light should come onwhen the ignition is on,but the engine is notrunning, as a check toshow it is working. If itdoes not, have the vehicleserviced by your dealer.If the check engine light comes on and stays on, whilethe engine is running, this indicates that there is anOBD II problem and service is required.Malfunctions often are indicated by the system beforeany problem is apparent. Being aware of the light canprevent more serious damage to the vehicle. Thissystem assists the service technician in correctlydiagnosing any malfunction.Notice: If the vehicle is continually driven with thislight on, after a while, the emission controls mightnot work as well, the vehicle fuel economy mightnot be as good, and the engine might not run assmoothly. This could lead to costly repairs thatmight not be covered by the vehicle warranty.Notice: Modifications made to the engine,transmission, exhaust, intake, or fuel system of thevehicle or the replacement of the original tires withother than those of the same Tire PerformanceCriteria (TPC) can affect the vehicle's emissioncontrols and can cause this light to come on.Modifications to these systems could lead to costlyrepairs not covered by the vehicle warranty. Thiscould also result in a failure to pass a requiredEmission Inspection/Maintenance test. SeeAccessories and Modifications on page 6‑4.This light comes on during a malfunction in one oftwo ways:Light Flashing: A misfire condition has been detected.A misfire increases vehicle emissions and coulddamage the emission control system on the vehicle.Diagnosis and service might be required.To prevent more serious damage to the vehicle:. Reduce vehicle speed.. Avoid hard accelerations.. Avoid steep uphill grades.. If towing a trailer, reduce the amount of cargobeing hauled as soon as it is possible.4-63
