&EPA United States Environmental Protection Agency Air and Radiation EPA420-F-00-041 September 2000 Office of Transportation and Air Quality Consumer Information What To Do With the Check Engine Light If you drive a 1996 or newer car or truck, you'll be glad to know that your vehicle is equipped with an early warning system which could save you time, money, fuel, hassles and even help protect the environment! What does that light mean? All '96 and newer cars and trucks have a powerful computer which manages and monitors the vehicle's operation. This technology is called "second generation On-Board Diagnostics (OBDII)." The computer makes sure your engine runs at peak efficiency and will alert you of any emission problems which need attention. How do I know my car is working correctly? You should see the "service engine soon" or "check engine" light flash briefly when you turn your vehicle on. That tells you the system is doing its job. After briefly flashing at startup, the light should normally stay out while the vehicle is in operation. What does it mean if the light turns on while I'm driving? If the light comes on and stays on, your car may not be operating properly and could have a condition which wastes fuel, shortens engine life, or could lead to expensive repairs if left unaddressed. It could also be polluting the air. For example, OBD can identify everything from a loose or missing gas cap (which contributes to smog) to a severe misfire (which can lead to engine damage). What should I do if the light comes on? Don't panic! The car will not stop running or self-destruct. It's just telling you to seek attention soon. If the light is blinking, a severe engine problem like a misfire is occurring which should be addressed quickly. You can still drive safely but should minimize driving. Try not to drive I Printed on Recycled Paper ------- the vehicle at high speed or with excess weight. Seek repair assistance quickly. When you reach your destination make sure the gas cap is not loose or missing. (Don't refuel with the engine running, as that may turn the light on.) Make an ap- pointment with your repair technician for diagnosis soon. Delaying assistance could lead to more expensive repairs or damage if left unattended for too long. my do I my car the shop? Ask your repair shop if they are trained to work on OBDII equipped vehicles. A modern repair shop or dealership should have an OBDII scan tool to diagnose the cause of your vehicle's problem. The technician will connect a small, hand-held scanning device to your vehicle's computer (usually through a connector under the dashboard) and download special codes which help to pinpoint the problem(s). The technician then uses a manufacturer recom- mended repair protocol to fix the vehicle based on the registered code(s). After the repair is complete, the technician will use the scanning device to make sure the repair was successful. OBDII actually helps repair technicians do their job more quickly and reliably (avoiding unnecessary repairs and returns to the shop), saving you money in the long run! I do light If the problem that caused the light to come on disappears within a few trips — perhaps after the gas cap has been tightened or a fouled spark plug has cleared — the OBDII computer will turn the light off. This is not an indication of a faulty OBDII system. In fact, the system is doing its job to verify that a problem existed that has been fixed or gone away. Your car needs no special attention unless the light comes on again. I do to my car is not the Today's vehicles are amazingly sophisti- cated and highly efficient. OBDII helps to make sure these new vehicles are running in top shape. But you still need to make sure that you maintain your vehicle accord- ing to the manufacturer's recommended schedule. Keep up that routine maintenance and keep an eye out for your check engine light; you'll be more likely to get extra years of service out of your vehicle and save money (both in fuel and repairs) while helping to do your part to protect our environment. As always, if you really want to do what's best for air quality, drive as little as possible. Combine trips and car- pool when possible. I get information? You can access documents on on-board diagnostics electronically on the Office of Transportation and Air Quality (OTAQ) Web site at: http ://www. epa.gov/otaq/obd.htm You can also contact the OTAQ library for document information at: U.S. EPA OTAQ Library 2000 Traverwood Drive Ann Arbor, MI 48105 (734)214-4311 ------- |