powdrhound

For the first time in 6 years of owning this car, I got a CEL. I noticed it this weekend at the track but can't recall when in popped up. I'm curious if any of the technical types on the forum here have any experience with this. I scanned it with durametric and pulled up the code P0444: Porsche fault code 98 - tank vent valve. This seems to be the culprit as all the emission readiness codes are set to PASS and there is nothing else of note. You can ignore the the CAN time out PSM as that is normal since the whole PSM system has been removed from the car years ago when the Cup ABS system was installed.

I did a little bit of google work on this and it seems this MAY be the valve that opens then the fuel nozzle is inserted into the filler neck and allows fuel vapors to be diverted to the charcoal canister during fueling. In PET it's referred to as a "bleeder valve" part # 996.201.143.01. I do however hear the clicking noise when the flapper in the neck is pushed in which indicates that the valve seems to be working, but what do I know? I spoke with another Porsche mechanic and he said this error code may be referring to some valve on the engine. I'm not sure about that however. Any ideas from the pros here would be appreciated..

[url=https://flic.kr/p/RtuyHQ]

TT Surgeon

My '03 c4s dropped that code once, I think it was that canister vent valve.

Kevinmacd

I have noticed not so much on the Pcar, but if you overfill other cars it seems to kick off a code due to fuel backing into the canister. Run it awhile reset and see if it goes away.

Carlo_Carrera

Also check your fuses. If I remember correctly sometimes a blown fuse can cause this error code.

ReidN

OK had this exact one. For me it was the plastic housing around the gas fill cap under the inner fender liner. Took 2 trys and a smoke machine to figure it out. One of the small vacuum lines attaches to a plastic barb. The barb had a hairline crack. When we saw the smoke, which took a while to show up. We touched the barb and it broke off. This is actually a common place for this to occur I have found out. Let me know what you find out. Cheers

powdrhound

Thanks for the input guys. I just cleared the code with the engine off. Once the car was started the same P0444 reappeared but the CEL did not. I let the car idle for about 30 minutes and it finally dinged and the CEL came back. I cleared it again and the CEL did not come back but I'm sure it will once the car is driven. I've checked the E6 fuse but it's ok. I figured it would be since I could hear the vent valve click when I depressed the filler neck flapper valve. I'm starting to lean to the idea listed above by ReidN, there has to be a leak somewhere in the lines or the vent valve itself. I'll investigate further tomorrow.

Initially I though this may have something to do with the sea level altitude the car was run at this past weekend as it normally lives at 5200'+. I had a low fuel pressure alarm when I started the car at COTA which turned out was caused by the higher vacuum created at sea level compared to 5200' thus pulling idle pressure down. My static fuel idle fuel pressure is 3.2 bar but at COTA it dipped to 2.9. A simple increase of idle fuel pump output fixed this. This led me to think that maybe altitude had something to do with the P0444 also but that's not the case.

Macster

Maybe this will be of some help?

powdrhound

Thanks Macster! I wonder why the fault code reads "tank vent valve" instead of the canister purge valve like in the maintenance document.

garrett376

Isn't that Durametric's version/interpretation of the code? They likely mislabeled its actual meaning.

powdrhound

Macster, do you know where exactly the "EVAP canister purge valve" is located and the part number for it? I'm thinking it might be 996.605.123.01 (attached to the secondary air pump bracket) but it's not very clear in PET or the maintenance manual link you provided for the trouble shooting of code P0444. It's either right near the EVAP canister (front right wheel well) or more likely on the engine near the intake somewhere. Any guidance or pics would be appreciated.

I found a picture (see link below) of what is supposed to be the EVAP purge valve but it looks like it's pointing to the N75 boost control frequency valve (996.605.155.00) instead. Obviously that is wrong.

https://www.renntech.org/forums/topi...r-purge-valve/

Thanks!

Kevinmacd

This may help, i know its 4cs might be close to the same location.

https://www.renntech.org/forums/topi...evap-canister/

Macster

Not sure where it is. My Turbo references have no drawing diagram.

But visit this link:

http://www.autoatlanta.com/porsche-p..._911_parts.php

Click on the Carbon Canister page and I think that wil show you where the part is located and its part #.