Black plate (64,1)Cadillac STS Owner Manual - 2011If the light continues to flash, when it is safe to do so,stop the vehicle. Find a safe place to park the vehicle.Turn the vehicle off, wait at least 10 seconds, andrestart the engine. If the light is still flashing, followthe previous steps and see your dealer for serviceas soon as possible.Light On Steady: An emission control systemmalfunction has been detected on the vehicle.Diagnosis and service might be required.An emission system malfunction might be corrected bydoing the following:. Make sure the fuel cap is fully installed. See Fillingthe Tank on page 6‑9. The diagnostic systemcan determine if the fuel cap has been left off orimproperly installed. A loose or missing fuel capallows fuel to evaporate into the atmosphere. A fewdriving trips with the cap properly installed shouldturn the light off.. If the vehicle has been driven through a deeppuddle of water, the vehicle's electrical systemmight be wet. The condition is usually correctedwhen the electrical system dries out. A few drivingtrips should turn the light off.. Make sure to fuel the vehicle with quality fuel.Poor fuel quality causes the engine not to run asefficiently as designed and can cause: stallingafter start-up, stalling when the vehicle is changedinto gear, misfiring, hesitation on acceleration,or stumbling on acceleration. These conditionsmight go away once the engine is warmed up.If one or more of these conditions occurs, changethe fuel brand used. It will require at least one fulltank of the proper fuel to turn the light off.See Gasoline Octane on page 6‑7.If none of the above have made the light turn off,your dealer can check the vehicle. The dealer has theproper test equipment and diagnostic tools to fix anymechanical or electrical problems that might havedeveloped.4-64