Hello..
On our 2002 A4T we have been having issues with trouble codes.
Our most recent take to the dealer resulted in the following.
P1111 oxy sen control Bank 1(its a 4cyl) system to lean
P0420 catalyst system efficiency below threshold
P0455 Evap canister (large leak)
So the dealer attempted the following: attempted to set readiness codes- readiness not setting, chk for vac leaks.
I have replaced the upper and lower oxysensors, and new fuel cap. Code p0455 has returned and Its prob irrelevant but it seems to appear when it hass rained.
I have read on this fourm about the Evap Valve. Can anyone direct me to its location ,, any help would be appreciated Thanks Cory

 

Code P0420 will return with time depending on how bad the cat is damaged.
As for the valve your looking for its called the N80 valve and it sits directly on top of the air box, (small valve with an electrical connection)
I would also get under the car and check the evap lines running from the back of the car to the front to see if there are any punctures in the lines, right front tires blowing out sometimes damages the lines.

 

thankyou Audi tech 79 . I will look over . Any other suggestions as to what to look for, the audi dealer spent 3hrs and couldnt find any reason.

 

EVAP system leak is probably the cause for all the codes so check all the pipes out

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