I have a 2010 Chevy Impala. I had an issue with someone stealing my gas, so I bought a locking gas cap. I soon realized that it didn't seal properly and my engine light came on. I put the original gas cap back on, and two weeks later, the engine light came on again. The code is P0449 which says it has something to do with a failed solenoid? When researching, I saw that if you switch from regular gasoline to the E85, if you don't drive a minimum of 11 miles, this will cause the engine light to come on. I know I've done this several times, but I want to know if my only option is the dealership resetting the computer that monitors the fuel system?? If this is truly the problem, why should I pay them almost $200.00 to reset it, if there may be a faulty piece in the car? Does anyone have any suggestions on how to do this without paying such a large fee?