Acceler8

Just checking my memory... Secondary Air inject. Bank 1, bank 2 lean = o2 sensors... right?

Always Overcharged

I have a feeling this can be related to the evap system.Check valve function

MP4.2+6.0

More likely just a bad vacuum line. Check them first.

jazzmegood

Turned out to be a deteriorated vacuum hose right underneath the plastic cover over the top of the engine. Replaced with 79 cents worth of tubing from auto parts store, cleared codes with Vag-Com, the light didn't come back on. All is well.

ttuling

The additive code means the computer has a to add a bit to the MAF sensor reading to match what the O2 sensors report, because e.g. of a small vacuum leak. The multiplicative code means the computer has to multiply the MAF sensor reading to match what the 02 sensors report. Other things could cause that, but in my case it was an underreporting MAF sensor. Search for g/s readings is you want something to compare against.

I wouldn't think it likely that oxygen sensors for both cylinder banks would simultaneously fail, and in a way that doesn't set any of the many available oxygen sensor codes.

Tom

audivotary

the MAF sensor under the 7 year 70,000 emissions warranty. Audi issued two letters extending the warranty for both the MAF sensor and the O2 sensors to 7/70.

BrianC72gt

I replaced every inch of mine after removing all of the plastic covers in the engine compartment and spending some quality time chasing all of the hoses, tees and connections. I bought 8 feet or so of the original stuff from Brunos, my local independent with change left over for 10 bucks and had at it. All those codes are gone!

Fortunately, the car has a furtile imagination and produce new different ones...