Chrysler Repair: MIL is on, locking gas cap, fuel cap

Question
Not positive but i believe someone was trying to siphon gas from my 06 sebring. My fuel door was open the fuel cap off and the resticting door at the opening missing. I replaced my old fuel cap with a locking cap. 4 days later my MIL came on. I took it in to have the code read and was told it was my fuel cap. They reset the light. 5 days later my MIL is on again. Could the restricting door thats missing be in my gas tank and causing the MIL to go on? Possibly the new locking gas cap?

Answer
did u get the locking gas cap from the dealer or any store??
U need one from a dealer so that it is a tight fit and does not turn on the check engine light. After that u might need to take it to the dealer for inspection.I live in Atlanta I could look at it for u