Help tracking down a recurring Evap CEL?

[phillsam]

Hey guys i could use your help,

I just recently bought a 2007 Audi A3 2.0T FSI w/ DSG.
It's high mileage body with a full top-end rebuild about 1.5k miles ago due to the previous owner neglecting the timingbelt .


Im getting a recurring CEL P0455 and P0422 - Both for an Evap leak (one large and one small)
As I understand it, P0455 can also be triggered when the Evap system cannot pull a vacuum.
Additionally, I have seen a Lean at Idle code but it hasn't come back in a while.
There has been no noticeable decrease in performance or rough idle.
There could be a slight MPG hit, maybe 2-3mpg?

So far I have replaced the Fuel Cap, Fuel Filter, and Evap Purge Valve(n80).
After replacing those I drove for over 300 miles in varied conditions until it came back on.
I cleared the codes again and within 40 miles, the CEL came back.
A recent Evap system smoke test did not show any noticeable leaks.

Could a faulty PCV valve throw those codes?
Where else would you look?
next steps?

Thanks in advance!

[giuseppi]

Replace charcoal canister, should solve the problem - I had the exact same codes, but mines a 2009.

http://www.audizine.com/forum/showth...Detection-pump

[phit]

When you replace your canister, you need to blow the line out going to the purge valve. Purge valve needs to be removed to do this , your purge valve may already be clogged. The bits of carbon are breaking up and hold the purge valve open. That's why purge valve and carbon canister get replaced together. Have fun replacing the canister on your A3.