CEL - P0456 - EVAP Small Leak troubleshooting *SOLVED*
 

I've had the car for one year and 2 days and got my first CEL yesterday. [:o]

When I sicked my VAG-COM on it, I got this code:

16840 - EVAP System: Very Small Leak Detected
P0456 - 002 - Lower Limit Exceeded - MIL On

I had this code last fall (intermittent, no CEL) and reseating the hoses on the purge valve behind the airbox solved the problem. No such luck this time.

I leak tested using block 71 in Basic Settings. I removed and replaced the gas cap. I jiggled the hoses on the purge valve again. So far the leak tests have all come up Small Leak, except when I disconnected the left-hand hose from the purge valve and plugged it.

Here's the purge valve:

http://www.patzcatz.com/audi/evapleak1.jpg

Here's the hose I disconnected and plugged, which resulted in NO leak detected:

http://www.patzcatz.com/audi/evapleak2.jpg

And a diagram out of the Bentley manual:

http://www.patzcatz.com/audi/evapleak3.jpg

What I'm wondering is, if disconnecting the purge valve and plugging the line stopped the leak, does that mean my purge valve is bad?

I'm going to buy some reusable hose clamps today, and do some more troubleshooting. So far that one connection was the only one I could remove easily last night without destroying the one-use clamp.

RE: CEL - P0456 - EVAP Small Leak troubleshooting *SOLVED*
 

I dropped by the local VW dealer on the way home from work and picked up a purge valve. Put it in, cleared codes, ran evap flow and leak tests, passed, problem solved!

Hey kpatz,

By any chance you know the part number? I just got the same CEL last night. It's easy to change right?

Thanks,

cd

The one for a 2.0FSI is 06E 906 517A. I don't know if it's the same on other years/models.

Quick way to check N80 and ECU. But I still question the LDP.

See here.