ppinto1

I've had the car for 2.5 months (and about 5k miles), and I've been back to the dealer for the third time on the same issue (engine malfunction indicator).

The dealer is wonderful about taking me in and getting me into a loaner - my best experience out of 5 CPO's I've had. I'm not sure if this is because it's an A8 - or if this dealership is just great with customer service (or the others bad, or the brand improved...) But, I wish I didn't have to see him so much

The first time, they said it was malfunctioning cam position sensors, and both intakes were changed. The second time, they said it was flagging one of the cats as operating with poor efficiency. The procedure they had to follow was to reset the computer and see if it comes back.

I asked if it could be a bad O2 sensor, or if the malfunctioning cam position sensors caused the engine to run too rich and damage a cat. The dealer tech said that both concerns were impossible - that the computer would know. I don't think he's correct, having had similar issues happen in the past (and being responsible for my own maintenance each time the CPO warranty expired). But, since they're doing all the work for free, I don't mind.

The other oddness they can't seem to reproduce is in the transmission. Occurring mostly when cold, the transmission will rev 200 to 400 (or so) RPM before harshly engaging a gear. Other times, it seems confused - kind of like a hesitation, but almost feeling like it's accidentally in two gears at the same time (sounds impossible, but really depends on the number of clutches in the automatic).

Once it's warmed up, this is rarer. To me, it feels like it might be a software issue - or a bad sensor. If I went old school, I'd think the valve body gasket had a tear

I'm not sure if this matters, and I'm wondering what others' experience has been. The temperature gauge seems to take a while to settle in the middle. I park in a garage that's always around 55 degrees Fahrenheit - and the car will often take 15-20 minutes to fully warm up. Thermostat?

Any input is greatly appreciated.

Jack88

Mine takes about the same time frame to reach full temperature in the morning. The coolant is also run through the transmission to help get it up to temp quicker, which makes it take longer to warm up.

As far as the harsh gear engaging, I do experience a harshness when accelerating from a low speed to near stop where it feels like the car lags in kicking down to the gear it needs. The longer the lag, the harder the kickdown when it occurs. I do believe it is software related, as it has always done it, most prominently when cold, and has not gotten any worse over the past couple years. However, I had the transmission updated to the most recent version, and it has not been fixed.

ppinto1

Thanks Jack88. I was hoping the update would be the silver bullet. It's comforting to think it won't get worse, though.

The_Capt

I've had same issue with mine, also when cold. Hasn't gotten any either, coupled with my extended warranty coverage I haven't bothered taking it in unless it's real serious. The woes of german software engineering. ;-)

ppinto1

Update: The dealer called yesterday to tell me what they found. The engine light is coming on, conclusively now, from a bad cat. They didn't say which one. There are none in North America, and I'll have to wait at least two weeks for a replacement.

Sidenote: The same thing happened when the steering rack blew a seal in my 2004 A6. Turn around was nearly a month.

As for the transmission, they aren't able to replicate the behavior, but they did take a look at the fluid - which, to them, seemed discolored. They sent it off to Audi to have it analyzed I thought that was pretty cool; but, I still think it's not mechanical. Maybe I'll get a transmission fluid change out of it. I was planning to do one at 100k, anyway. The "lifetime" oil in my A6 looked quite dirty each time I changed it (about every 70k), and that trans went for over 250k.

Another good thing is ending up with an A8L TDI loaner. I always get the A6 - which, after an A8, doesn't feel as nice as it used to. Hopefully, I'll have the loaner for the duration of the service. I guess there's a chance they'll give me the car back while they wait for the cat.

tcounts

I'm having the exact same experience with my transmission. I own a 2012 A8L 4.2 Quattro (34K mi) and when leaving from a dead stop, it's like the transmission slips then grabs all of a sudden. I've had it to the shop twice and no joy. They performed a software update and an adaptation relearn but I see no change whatsoever. It seems worse when its cold but can be unnerving for that microsecond when you're pulling out into traffic and think the car's not going to get moving in the time you need it to.

After owning many BMWs, Mercedes, and Lexus, I'm very disappointed if this is "normal". I won't own another if this is typical.

Tom

ppinto1

I'm not sure if it's typical. The adaptation seemed to change things at first, but it may have been my imagination.

I searched a bit about this, and haven't found complaints to be pervasive.

It's weird. It's not so much that it slips for me, as it feels like the transmission is stuck in the wrong (higher) gear and reluctantly downshifts. The problem is accentuated by the engine computer pulling power to accomplish the shift while it feels stuck (I'm assuming).

I drive in a lot of traffic in the DC/Metro area, as well as back home in the NYC area. I've not had this be an issue yet - but I'm aggressive when I think I'll need to accelerate briskly.

The_Capt

My local dealer did the same thing, tranny software update coupled with adaption relearn.....neither fixed this shifting issue. I agree it's a possible hazard should you need to quickly accelerate and the tranny is stuck in too high of gear.

MP4.2+6.0

I just posted in another thread on tranny (the one w/ the adaptive cruise error), so maybe read that too.

For OP, agreed if engine controls malfunction too long, that can take out cat. Sounds like they eventually figured that out.

On tranny, yes go toward fluid change if they will do it, and be sure they run the adaptation. Best if the motor/throttle adaptation is done too. Others are replying though that was not a cure all. At least early ZF 8 speeds were not known as the smoothest, this forum included as I recall from various posts back years ago now. My D3 W12 6 speed with a lot more miles drove smoother than a 2012 era low miles (and then near new) 4.2 they gave me as a loaner during one CPO service that took most of a week.

Later I did run into a shift issue on my D3 W12, and indeed it was most likely the seal between the valve body and the case as OP theorizes in the opening post. I also did the solenoids so can't be 100% sure which it was, but it was cured and then drove like new and very smooth again, both then and now almost 25K later. But I'm probably the only forum guy with a D3 (or 4) who ever went deep inside one like that. BMW forums usually have better tranny info and deep dives than Audi ones, including specifically the valve body (Mechatronics) seal. BMW (and Jag) ZFs are basically same as Audi for the given era other than no AWD...until recently.

For the cold run stuff, I would still urge someone to dive into parts diagrams. A hunch is there is an inline thermostat relating to tranny cooling and/or warm up function, separate from motor one. Motor one should be MAP (fast acting electrically assisted) on these, so if it is not working to general spec, you end up with a code and dash light show. Had it on my W12 when a rubber gasket inside the housing around the mechanical part of thermostat peeled away and then stuck part open. It would only code though if extremely cold on long drives (0-10F); otherwise I noticed it was basically just slow to warm and temp stayed lower than normal in winter. D3 W12 one below--yes, the can fail open and can be a pure physical fluke... FSI 4.2s will be a different physical design, but as I recall the same MAP concept--a.k.a. "the ones with a wire sticking out."

Hughey

Hi, new member here. Just wanted to say that I have the sluggish transmission issue as well. I only notice this when I have come to a rolling stop, that is I don't come to a full stop, and then accelerate hard. It does feel like the transmission is in too high a gear and has no torque to get the car moving, then it finally kicks down and off we go. Other than this one issue, the transmission is very smooth and responsive. It anyone finds a fix for this I would love to know about it. This is my only gripe about my car. 2012 A8L, 35,000 miles, CPO purchase about two months ago.