Incaico

I can tell you that the dealer put over 200 miles on mine during the service. I questioned the mileage and they said that in order to fully understand the problem, it had to be done. My issues began with an O2 sensor going out, then the manifold, then one fuel injector, then all, before the engine light stayed off...so far so good.

dvs_dave

Unfortunately that is total BS.

It's an inherent feature with all gen 1 gasoline direct injection engines, regardless of manufacturer, fuel or oil quality. What it is, is a design flaw that no manufacturer will admit to as it'll cost them a fortune in warranty claims and class action law suits. Instead they've all clubbed together and come up with this "user error" cheap gas/oil excuse.

I'm telling you, it's going to bite them all real hard on the *** before too long.

MP4.2+6.0

To be sure it can now pass a smog test in many states even with no CEL on, for "readiness" it needs to do a complete test cycle , which involves a bunch of steps, including running the motor at a couple of different RPM's w/in very narrow tolerance for several minutes. If it can't complete this, the "readiness codes" don't all reset to good during the learning phase after a CEL clear. States and the EPA have wised up to folks resetting a CEL like five minutes before a smog test on a laptop or with a handheld scan unit. Thus many now test specifically for the readiness codes reading good, or the car still fails--they tell you come back in a few days in that scenario or send you to the state referee test place (like here in CA) if you claim it just got fixed. As in, that "option" sounds like the full underhood close up "strip search" to avoid like the plague.

Having gone through the "readiness" drill on my 2000 A6 4.2 right before a smog check I had to pass before tag expiration in just a few days and w/ a vacation looming, I tried carefully do the full readiness reset with the documented procedure w car parked. I just couldn't hold the elevated RPM's steady and within a very narrow range for the required time, even though trying for an hour plus with steady nerves and leg. The fallback is to complete a bunch of driving cycles (typically 5 to 10) involving steady freeway speeds for at least several minutes; that's the simple way it resolves over some days. To speed it up, you have to nail all the exact test parameters in fewer cycles. I found the process posted when I searched for Audis and readiness code process. Basically, a long drive once fully warmed up where you hold it in the RPM ranges for a fair amount of time for the hardest to simulate part of the test. On the A6 that was top gear right around 60 MPH. As in, cruise on w/ light freeway traffic and stay your course until the bitter end (or imminent accident failing bail out). Took me on a one time 50 mile freeway circle in lighter weekend traffic to be virtually sure I had it several times over, which on an (easy) scan of the VAG COM readiness codes found I was indeed successful. And yes VAG COM of course allows a CEL reset, but doesn't (and probably legally can't) allow a recode or adaptation to magically confirm sudden "readiness."

Assuming the dealer here wanted to be sure they had the OP's car fixed (for me it was a fouled plug, so I knew I had it fixed), they likely either wanted to repeat it a few times, or just went w/ the simpler drive it several days approach where it tends to set the readiness codes w/out a lot of process rigor.

Incaico

I will be keeping an eye out for this. worst case, since I have a 4 year 40k warranty with the dealer, I will let him deal with it...after all, I will always be taking it back to him for service, this way, I get the newest loaner available. Looking forward to my 55k service. Can't wait to see what type of loaner I will get...