fault codes po421 and po431
 

im getting fault codes po421 and po431 what could be the cause of this? I might be burning a little bit of oil and i dont think both of my cats are bad.

2002 a4 3.0

RE: fault codes po421 and po431
 

Those fault codes don't exist on my DTC data charts, are you sure those are correct?

Cat efficiency codes would be P0420, and P0432 in which case you would need new cats.

RE: fault codes po421 and po431
 

do think both the catswould be gone ,or could it be something to do with the motor? I have 96000m on my 2002 a4

RE: fault codes po421 and po431
 

P0421 = warm up cat converter bank 1 below efficiency threshold possible causes are bad cat/ wiring/ HO2S sensor ( o2 sensor )
P0431 = bank 2 same problem

edit: just correcting a code[:-]I put P0321 instead of P0421:)

RE: fault codes po421 and po431
 

before you go changing your cats I'd check out the postcat sensors. Whats the mileage on your car?

RE: fault codes po421 and po431
 

96000

RE: fault codes po421 and po431
 

i got the P0431 too i had it for awhile, could be your O2 sensors or Bad cats which is my issue $2900 at dealer each side. I dont know what im going to do. Huge loss of power and bad gas milage.

RE: fault codes po421 and po431
 

ya there a hose that goes to your air pump, so you are going to get some codes. jusdt make it your self is cheaper