I have a 2004 Audi S4 with 88,000 miles and P0172 popped up. what does this mean and how do i fix it?

 

well p0171 and p0174 are lean codes, im guessing this is a rich code. check the airfilter for one, you could also have a faulty fuel pressure regulator, or maybe a saturated canister. im not a specialist on the B6, but those are where i would start.

btw, p0171 and p0174 are bank sensitive, so if that is your only code, it is that bank specifically. i think bank 1. but you could also have a contaminated MAF, ive seen those cause that rich condition as well..

 

P0172 is System too rich, bank 1


- fuel pressure regulator and residual pressure checking.(fuel pres. reg. is actually integraded in fuel filter on these cars/ easy fix)

-check fuel injectors

-check front and rear bank 1 (witch is passenger side) o2 sensors

- check evap emissions canister purge regulator valve -n80-





....maybe time for all new o2's and fuel filter... good luck