Help with P0456 - Ford Mustang Forum
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post #1 of 5 (permalink) Old 07-15-2019 Thread Starter
Jamesrion's Avatar
Joined: Jul 2019
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Help with P0456

I have a 2012 mustang v6, currently getting code p0456 small evap leak. I am trying to self diagnose as much as I can before having to go to a shop. Everything online is saying check hoses, and also gas cap. My stang doesnt have a gas cap, and from what I can see no cracks in the hoses. Anyone dealt it have tips on where to look? Could this be caused from axle back pipes I've put on it recently? Also there are no other codes popping up at this time.

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post #2 of 5 (permalink) Old 07-15-2019
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If you don't have a gas cap, then whatever is plugging the top of your tank filler pipe is allowing a vacuum leak.

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post #3 of 5 (permalink) Old 07-15-2019 Thread Starter
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Yes, no cap, looks like this. So you're saying a seal inside? Sounds like a shop job huh?
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post #4 of 5 (permalink) Old 07-16-2019
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There is an "evap cannister" in the fuel fill system; I think sometimes they get clogged or full of gas and that will trigger that code. There might be a TSB on it and/or the cure is a known thing, if that is the issue.

Try some searches in this section and the other sections of this forum, I'm pretty sure there are threads on here with the full details.

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post #5 of 5 (permalink) Old 07-16-2019
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Try inserting the nozzle 4 or 5 times into the cas filler.
2012 V6 has a purge valve on the motor and that could be going bad also.
Looks like this
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