H3 Engine light PO455 EVAP help needed!
 

Hello everyone,
I am new to the forum and a new H3 owner. My 06 H3 has the check engine light on, with code PO455 EVAP Emmision system leak (large). I of course checked the gas cap and even had it replaced but light keeps coming on? I did read a post on a h2 with a similar problem but got a little lost. I know it could be releated hoses and/or some type of silonoid. Does anyone have any Idea's what else it could be and how difficult it could be to fix? I am taking it to the dealer soon since I just bought it, but I want to be educated on the issue.

Thanks in advance for the help in advance,

Philip

keep us posted on what happens

I don't have access to SI to look up that code, but can you hear an exhaust leak anywhere? Maybe get under it and listen for a hiss, ping, or knocking sound. Also check around your exhaust manifold. A code referencing a large emission leak would seem to be more than the gas cap to me.

A code p0455 most likely means one or more of the following has happened:

• A loose or improperly affixed gas cap
• A non-conforming gas cap (i.e. not factory/original brand)
• Other leak or damaged piece in EVAP system

Possible Solutions

With a p0455, the most common repair is to:

• Remove and reinstall the gas cap, clear the codes, and drive for a day and see if the codes come back.
• Otherwise, replace the gas cap, and/or
• Inspect the EVAP system for cuts/holes in tubes/hoses (you may hear a vacuum noise or smell fuel), repair if necessary

My 06 has also had P0422 (small evap leak) been to the dealer like 5 times and replaced the gas cap 3 times....still has it. The dealer said they smoked it everytime and cant find anyting.

Problem hopefully solved
 

Dealer today said there was a broken wire on the vent silinoid. I will keep everyone posted if this solves the issue.

I had a gas cap failure and thought I get nuts as I several times checked the gas cap before I finally found following:
I added a fuel door for what I needed to remove the plastic cover around the infill pipe. When putting back a rubber seal/lip did not slip over properly and caused the problem.

It is back grrrr no more large leak but it comes back PO422 or PO442 (small evap leak) I dont hear any leak, got the new gas cap, the siloniod wire has be repaired. I am out of ideas. At this point I just use my OBD II bluetooth with my Torque app to clear the annoying code but of course I would love to actually fix the problem. I really just dont have the $$ to take it back to the dealer

If there is no leaks it could be a control valve not doing it's job.

This is a new one!!!!! Thanks for the post, just wondering if you checked all those vacuum hoses under the rear near the gas tank? There is some kind of huge canister (some kind of carbon filter or something) that has a hose that goes to the gas tank.
When I saw all that mess, thought to myself "this is gonna give problems at some point"
Good luck and will keep eyes out for any other posts or info on the issue.