Forgive me if this has been covered, I did a quick search but didn't find what I was looking for. Anyway, recently I replaced my fuel tank and during the process somehow my battery died, I may have left something on, The car wasnt used for about two weeks so maybe I have other problems, car works fine now though. Basically when I charged the battery and turned the car on, I had a check engine light, It was something to do with air fuel, I wish I wrote the codes down but I didn't and I have no way of getting them again. I cleared the codes, now my question is that since the light hasn't come back on, am I safe to assume that there are no problems, Would the light come back on if it was still a problem, or does the car still have the problem, but doesnt tell me because I cleared the code. Now if I were to disconnect the battery would the code come back. Thanks for the help.