help Large leak in EVAP system Trouble shooting code P0455

[MaClaud10]

i have a 1998 BMW 323is and the check engine light came on i went to check it at Auto zone and they told me that i could have several causes one of them is the fuel cap but i told them that it wasent posible i had bought a brand new fuel cap from BMW not to long ago, they also told me that it could be something with the EVAP canister but im having trouble findidnt it to check the hoses, something else they told me is that the Purge or Vent solenoid could be defective can you help me locate this items to check them i been looking on the web for too long and i want the car to run well

[johnnyBgood]

Originally Posted by MaClaud10

i have a 1998 BMW 323is and the check engine light came on i went to check it at Auto zone and they told me that i could have several causes one of them is the fuel cap but i told them that it wasent posible i had bought a brand new fuel cap from BMW not to long ago, they also told me that it could be something with the EVAP canister but im having trouble findidnt it to check the hoses, something else they told me is that the Purge or Vent solenoid could be defective can you help me locate this items to check them i been looking on the web for too long and i want the car to run well

Hi, I had this same problem code & it was the fuel expansion tank. One of the the plastic hose fittings was broken off causing a large evap leak. It is located behind the passenger side rear wheelwell.....you also check the fuel charcoal canister located under the spare tire in the trunk, there is a drum cover that you need to remove. It will be under there. The cause is most likely the fuel expansion tank behind the wheelwell though!
here is a link to help you identify them......
johnny,

RealOEM.COM * Part Category Selection

[paco1076]

Just bumping this thread. I just had the same issue with my E36 M3 and this was the problem. The expansion tank behind the passenger rear tire.


Thanks for the help.

[paco1076]

UPDATE:

You can peak in at the Gas Expansion chamber to see if the plastic nipples have broken off by opening your gas cap lid and pushing the rubber boot through to the inside of the fender. Take a flash light and look in towards the front of the car and you should be able to see the top of the chamber. Might save you some time without having to take the inner fender well out.

I just did this repair over the weekend and had some struggles getting the chamber reinstalled. It was fairly easy to remove though.