P0451. Engine code given 2 an engine check by Autozone. Should I start by replacing the gas cap?

Question

I was told by an employee at AutoZone that it could be the gas cap or the fuel tank sensor because my check engine light will go off/on anytime I unscrew/screw on the gas cap. I was told to take the cap off and screw it back on and let the system build pressure back up and run it for a couple of days and if the light went off then the gas cap was the problem...anytime I'd do this after the set amount of days, the light would go off. I was also told it could be the fuel sensor if I'm losing gas mileage but my gas mileage is fine.

Answer 1

No, that code is not for the gas cap. There are some test that needs to be done to determine what the problem is. You may have to have the dealer or an independent shop diagnose the problem for you.