Last evening I was driving and my check engine light came on. It wasn't flashing so I felt pretty safe and the car is not behaving any differently.

I had checked all my fluid levels early in the weekend so I was pretty sure all that was good. I had gassed up the day before. When I made my first stop on my "errands" last night, I unscrewed and re-screwed my gas cap.

I stopped on my way to work this morning to get the codes read at Advanced Auto (for free) and got a P1456 code.

I think I am going to start simple and get a new OEM gas cap from Honda. I occassionally get a whiff of gas from that area of the car. One weekend ago, my car had been parked in a friend's garage while we were camping out of the area, and there was a strong gas smell in the garage, though it was attributed to recently purchased Jet Skis at the time.

Advanced Auto wanted to sell me an evaporator canister.

Is the new gas cap the best place to start? If that is the fix, how long will it take for the car to clear the code on its own.

Thanks!