My 2007 A4 1.8T just failed emissions... Error code P01701 Bank one Lean... hmm not sure were to start looking wither an O2 sensor or purge valve... vacum leak???

 

Is it a constant code? Or did it come once? Do you have an exhaust?

 

Yes... The code appeared about 1 week ago and has remained on since. I have a stock exhaust with no modifications to the exhaust or engine... should I replace the O2 sensor? how many O2 sensors does the 2001 a4 1.8t have? any other suggestions?

 

'01s have 2 O2 sensors, 1 before and 1 after the cat. I would just put the code into a search on here and Audizine and see what comes up. I'm sure its been covered before.

 

I tried a search under cope P01701 and did not have any luck...

 

i think you mean p0171 system too lean bank one. i had the same thing bout a couple weeks ago. i too thought it was my 02 sensor but i talked to a few people on here bout it and they said to change the maf. so i did and sure as hell that was the problem. definately start there.
https://www.audiforums.com/forum/sho...ning+lean+noob

 

Redline380... thanks for that thread... I read a lot of stuff about O2 sensors creating a lean code but I am on board with a bad MAF... I will probably buy some cleaner tonight and try that until the part comes in... Thanks again for your help!

 

definately holla back with results