My boyfriend changed the fuel filter, air filter, and oil and checked some other things on my 2002 ford escort and a little while later my check engine light came on. Is this most likely because he did those things and it triggers the light to come on, and if so is there some way I can check without paying to much moneyor make it go off? Or is it most likely something bigger that I really need work on? Nothing seems to be wrong with the car. It shakes at idling speed but I think that's the motor mounts it did that quite a while before the light came on.
It's likely you'll have to have the light turned off by a qualified agareg. If you've reached certain mielages the light automatically comes on to alert you to service the engine for optimum efficiency even though you performed a tune-up. It could also be an item in the EGR system that malfunctioning.