speedyc43

So Im trying to get my emissions test done to finally get this car on the road and the only thing stopping me is this bloody code. Now Ive done some things to try and figure this out but I keep coming up with nothing. The first is I cleaned out the little MOT thingy and it hasnt helped. Next I did a smoke test, I got my electric air mattress pump taped a cigar to it and blew it into the two lines connected to the MOT module. The only result that I got was when I blew it into the line with the elbow in it. The smoke started coming out the driver side rear fender. Upon closer inspection I found the Charcoal canister and attached to it was some sort of valve which had 2wires running to it and one rubber hose. Now my question is whether this valve should be closed when its operating and only open when its supposed to vent. I found it to be open when the motor was off. As for the gas cap I ruled that out because it seems to be holding vacuum after the MOT makes some noise. If anyone has any run ins with this problem, your input would be greatly appreciated. Thanks

503C43 ////AMG

most common failures are the gas cap not being on all the way, the big hose into the canister, or the gas tank lock ring. I believe the valve should be closed if the motor isn't running, I could be wrong

found this on another forum:
Same issue a while ago,as per my local dealer parts guys there are four parts that could be defective, gas cap, one valve in engine compartment, one valve near the charcoal canister and the canister it self, I replaced the parts based on lowest to highest cost, the valve near the canister was third on my list and turned out to be defective, as electrical parts could not be returned, I still have the old valve from the engine compartment which was good I think it's called a "regenerator",if you want I could send to you for troubleshooting.

speedyc43

Thanks 503C43. Here is my update, i took apart that valve thats closest to the canister because it wasn't making any noise when I applied current to it. Turns out it was seized, it now makes a popping noise when I apply direct power which in turn closes off the air. Im going to reassemble now, wish me luck. As long as the wiring leading to this valve is good im confident the issue should be solved.

speed43

I like to try what you did here. Can you please explain which wire is the positive and how many volts you used to make it work?

speedyc43

It's basically an electro magnet. So it doesn't matter which is positive or negative. Also I just used 12v DC to make it work. I applied power and try blowing through the valve. Once it made a clicking noise it was closed.

speed43

Thanks. Is this the valve you are talking about?

speed43

This picture shows the "cup" put togther. The first picture is with it off.
I took it off to clean that yellow foam filter which was very dirty.

speedyc43

Yes that's the valve. I took mine apart completely. There is two clips holding the actual actuator inside the plastic housing which I had to pry out and it all came apart. There is a spring in the centre

speed43

Great, going to try it tonight. Im going to run a wire from the fuse box in the trunk. Do i split/cut either wire or do i just tap into by peeling one of the wires?

speedyc43

Just take it off grab two wires hook it direct to your battery and then touch the two wires at the connector if you hear a click noise it's probably working. Try blowing air through it. It shouldn't flow any air while under power.

speed43

Thanks!

speed43

I took apart the valve. It was stuck closed, but when we put direct power nothing happened.
We put it back together and now its stuck open. Good thing is with it stuck open i can now fill my tank without the annoying pump handle stopping every 2 seconds.
The bad thing is that now my low fuel light flashes after a few minutes with the car running.

Question, if i leave everthing as is will the fuel light flashing cause any problems!
The valve is $219.00 which i will be ordering next week.

Im just wondering if i can continue to drive without any issues till than?
Is there some way to trick the computer to not check whatever its checking so the light wont flash?

speedyc43

Yea mine was open continually before I had to do my e test. Other then the p0455 code everything will be fine

speed43

So your low fuel light also flashed? Did your check engine light also came on?
I found a used valve on sale so im going to give it a shot since its pretty cheap.

speedyc43

Yes to all your questions and good luck with your used valve

myworld

Thank you @speedyc43 for this post! Just pulled the charcoal vapor valve took it apart and cleaned it. The foam was crumbing when I took the cup part off, but I pieced it together when I put it back on. I pried the clips off opened it up. Sprayed maf cleaner re assembled. Put it back on the car and drove around. Checked codes. No more p0455. I'll drive it for afew more days. Pretty sure this worked.