P0455 & P0446 Codes; Help!

Alright, so I have a '96 328i and it's throwing P0455 & P0446 codes.

P0455-
EVAP large leak detected

P0466-
EVAP Shut off valve stuck closed


Any idea what the commonality and the most likely fix is?

Thanks,
Heidi

honestly this is a hard one. this is one of those fixes that 10 people can give advice and you just keep buying parts until you figure it out. the most common problem for an EVAP leak is a bad gas cap. the gasket around the cap gets brittle and no longer does it's job of staying sealed. you can pull off the cap and do a visual inspection of it. most likely this is not the problem because your code is throwing a large EVAP leak and i've only seen it throw small EVAP leaks. however, anythings possible. once you've eliminated that i would then start my way from the trunk(removing the trunk liner) and follow the lines all the way from under the car to the hood. look for anything out of the ordinary. hoses disconnected, hoses cracked pretty bad, odor of gas strong somewhere. just because is says the shut off valve is stuck closed doesn't mean you need a new valve. if you can't figure anything out you really need to have a shop perform a smoke test to determine the leak. good luck and let us know

Originally Posted by tchavera

honestly this is a hard one. this is one of those fixes that 10 people can give advice and you just keep buying parts until you figure it out. the most common problem for an EVAP leak is a bad gas cap. the gasket around the cap gets brittle and no longer does it's job of staying sealed. you can pull off the cap and do a visual inspection of it. most likely this is not the problem because your code is throwing a large EVAP leak and i've only seen it throw small EVAP leaks. however, anythings possible. once you've eliminated that i would then start my way from the trunk(removing the trunk liner) and follow the lines all the way from under the car to the hood. look for anything out of the ordinary. hoses disconnected, hoses cracked pretty bad, odor of gas strong somewhere. just because is says the shut off valve is stuck closed doesn't mean you need a new valve. if you can't figure anything out you really need to have a shop perform a smoke test to determine the leak. good luck and let us know

Say it is a bad gas cap. How long would it take for the engine light to go off? I'm in Texas and was supposed to drive up to Chicago (saw you're from there) today. How big of a problem is it? I don't see any gas leaking nor do I smell gas.

might impact efficiency, but shouldnt be fatal.

craig

Sent from my HTC Desire using Bimmer

haha that's funny. i moved here 2 years ago from houston. normally with those things you have to reset the check engine light and then either it doesn't come back on and it's fixed or it comes on when it reads a fault again. you could try changing the gas cap, have an autopart store reset the light and drive to chicago. like leusent said it's not fatal lol. you will prob just get bad gas mileage. i know of people that never fix an evap leak. if you want, when you get to chicago you could just come to the shop i work at and we can figure it out for ya. no charge (assuming the gas cap doesn't fix it)

Got a new gas cap but nobody in town would reset the code. Opened up the trunk and took out the spare. Don't smell anything funny. What exactly am I looking for?

you may not ever smell fuel with a leaky/loose fuel cap. it is something that is a common fault code, and is *usually* related to the fuel cap. it costs more to 'test' the cap than replace it, so i usually recommend replacing it.

the other code indicates a fault in one of the parts that control fuel purge. this may or may not be related to the other code, and i am not going to guess.

what i do know, though, is that the best way to check for a leak in the evap system is to find a shop that has a smoke machine. this will show leaks in the evap system much easier and allow the technician to better locate any faults.




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