aca6c5

Wanted to get some opinions on what needs to be replaced. So the CEL has came on and when i pulled the codes with my non vagcom scanner I received 2 codes P0420 and P0430. This has happened before and after erasing the codes and 155 miles later the light has popped back on.

Should I just go ahead and spend the money on replacing the O2's or should I save and replace the catalytic converters?
The A6 has 175k on the clock and from what I know is that the O2's have never been replaced.
Also does anyone have any pics on where the bank 1 and 2 O2 sensor would be located? Forgot to mention that its a 2.8

Thanks!

4Driver4

I think you should post what the codes mean.

Airbag

post cat o2 sensors are a reap pita to replace. until you realize you are going to have to just cut the wires, rip them out. and restring the new ones differently then its easy.

i just did a thread on this so search.

aca6c5

1st code P0420 Catalyst System Efficiency Below Threshold (Bank 1)
2nd code P0430 Catalyst System Efficiency Below Threshold (Bank 2)

So it appears that pre cat o2 sensors need to be replaced? Does anyone have a link to a thread for step by step on how to access and replace both bank 1 and 2 sensors for a 2.8l?

Thanks!!

4Driver4

Bad cats.

Just Me

well, or a sensor out of calibration and thus yielding that indication, right?

Or is that so uncommon that we can ignore the possibility?

2.7Lturbo

a vag-com would easily rule this out....

Just Me

How? You measure cat efficiency via the delta between sensor 1 and sensor 2

Absent calibration, how can anyone know if the subject or the test equipment is off?

I'm missing something here....

Grant

2.7Lturbo

there is a calibration/test procedure in vag com for checking O2 sensor health, and cat efficiency.

i cant remember the details, but it involves setting the test procedure and revving the engine to like 2500 rpm for 10 min or something like that,

at the end of the test it will give you a pass or fail for the cats.

their is also an autorun test on the o2 sensor heating elements.

another thing would be to check readiness codes. cars that sit awhile, can throw codes for not having readiness set, all you have to do is clear the code and drive around long enough for the readiness codes to set

aca6c5

Thanks everyone for the replies... Sadly it looks like Ill be off to the stealership to have them scan the car with the VAGCOM.