check engine light

My check engine light just popped on in my 95L legacy. I opened her up and noticed that the cap for the engine coolant popped off, would that cause the check engine light to come on? I put it back on, and even put my gas cap back on to make sure it was on right cuz I heard that could set it off at times, but the light is still on even though im sure you need to turn that off, it wont just go of by itself. Any thoughts on this? THanks

If you disconnect the negative battery terminal overnight, it will reset the engine check memory. When you reconnect it, the parking lights will be flashing, because it also resets your alarm, so you'll have to either use your remote to lock and then unlock the doors, or else start the car with a key that has the chip on it to get things back to normal. Of course you will also lose your radio stations and clock. If the light goes out...GREAT. If not, there is an ongoing problem that must be analyzed.
Cap