I have 2000 merc. Sable w/ 110,000 mi.
End of May ?10 my check engine light came on though the car is running fine. My shop (not the Dealer) performed a computer diagnostic and replaced the EGR valve. Several weeks later the light came on again-- they replaced the EVAP Valve Hose. About 200mi later the light came on again. They re-booted the computer?several hundred mi later the light comes on again. They claim the car is fine. They can?t get it to stay off. The car runs fine. Obviously the light is designed to tell you the car requires maintenance when there isn?t any discernable symptoms. My question?If I simply ignore the light is something really bad likely to happen without me knowing about it until it is too late or is the check engine light not that important?
Someone here has a file on his HD which answers this question. Take it to Autozone, and ask them to scan it, which is usually free. Tell us the codes, something like P0042, not the words they tell you. It is rare to have that light on with no codes to read, and the guys here need the codes, not just a light on.
That CEL (check engine light) is just a kid in class waving her hand trying to get you attention because she has the answer. You need to have the codes read. Some places will read them for FREE. Try Autozone or Advanced Auto Parts. Get the exact code (like P0123) not just their translation into English and post it back here.