A few months ago I got the "check gas cap" light, even though I couldn't find anything wrong with the gas cap. Did some Internet searching and didn't find anything much other than replace the gas cap. Do I replaced the gas cap with an OEM Motorcraft cap. I waited 20+ drive cycles for the light to go off, but it never did, so I turned it off with my scanner.

About 3 weeks later the light came on again. Clearly there is something else wrong with the evap system, but is there anything in particular I should check? I'm not real familiar with the system.

 

P0457 is the code

 

So did you replace the cap??? Because what you wrote above appears that you just reset the code and didn't replace your cap.


I had the same light come on. I put a new Motorcraft cap on and reset the light. It has never come back on. Eventually the original gas cap loses it's ability to seal the system and needs to be replaced.

 

Sorry typo...yes I replaced the cap with a motorcraft.

 

I did a quick search online, and found that if it's not the gas cap, it'll be either a cracked or rotten hose, or a damaged and cracked vacuum canister.

You may also want to check the actual threads inside the cap. there might be some crap in their preventing the cap getting a good seal.