Guys,
This is driving me crazy...

I've been helping a friend (This is a repost from another site) for me. with his 2002 TT and a very frustrating (intermittent!!) P0455 DME code. He needs to get through emissions inspection, in AZ they just connect to the OBDII port and the system won't show a "ready" state so it will fail.

We've seen several references to what the problem could be, just trying to narrow it down. We have the DME manual, shop manual (I thought it was complete) and completed a lot of research on the forums. Some things that will help,

- We need a full drawing of the tank vent system with the location of components; where is it in the manuals?
- References online indicate the simplified system for detection is as the attached. Where is the pressure sensor "5" located at? We've looked around the tank and the evac canister, doesn't appear to be anywhere near.
-We hear some kind of pump that comes on with the ignition, is that part of the evac system, where is it?
Attached Thumbnails

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Have you checked the gas cap? I had the same code, checked the cap and sure enough the rubber oring on the inside of the cap had dried out and cracked. Replaced the cap and the code hasn't come back.

 

I would say check the gas cap as well.

If not, check the Evap canister and all the vent tubes.

I am assuming the pump you hear come on is the fuel pump

 

 

Thank You for the drawing, do you have the I.D. for the numbers? The gas cap has been replaced. The pump I hear is the secondary air pump. My local shop has had it on their computer and operated / tested everything to do with the evap system and it all checks good...twice...

Tim

 

Which numbers do you need?

 

I'm looking for the fuel tank pressure sensor...is that #23?

 

Where is the pressure sensor?

 

The fuel pressure sensor is #9 on this illustration.



Found here on our website.

 

Number #23 is a Fuel Tank Vapor Valve

 

Thank you, we've had a devil of a time finding this sensor's physical location, from the drawing it appears to be right by the charcoal canister. It didn't appear to be behind the wheel liner, is it buried up there under the car by the diff?
Are these drawings from the Porsche PET?

 

Here is the location.



Yep, all the illustrations are from PET

 

Thanks for the quick response.

The picture seems to be pointing to "9" in your first illustration (below) this doesn't look like the sensor (pic of part on your website), is it just angle of view?

 

#9 in the first illustration is a fuel tank restraining strap.

#9 in the second illustration I posted is the fuel tank pressure sensor. Sorry if all this is getting confusing.

 

I meant "12" in the first drawing which I think is around the filler neck, your arrow is pointing in that area.