159515100

Below is an email message I sent to the service department where I take my car for service followed by their response. I looked in the Audi manual carefully and could not fine anything that supported their comments that what happening with regards to the ACC is normal. Anybody else have some experience with this that offer some input? Thanks as always.

Hi Larry and Kelly:

First of all, thanks as always for all of your help, it is appreciated. I have a quick question about my car for you both which can be answered at your convenience. I just returned from taking the car to Scottsdale and am please to report that it ran great and got 27.6 miles per gallon on the way down and 28.4 on the way back and that with me going between 70 and 80 miles per hour the whole way! Incredible car with incredible performance. My question is regarding three minor issues that do not require immediate attention but did want your input on them.

1: My car is equipped with the adaptive cruise control and on the way down after using it for about 200 miles it just stopped on it's own and gave me a message something to the effect that the ACC was not working and the sensors were not either. This lasted about 10 minutes and then I was again able to turn on the cruise control with it going off again about 5 minutes later with the same error message followed by the same pattern a third time and then it worked flawlessly the balance of the trip. It was early in the morning when this happened and somewhat foggy. Interestingly enough, it happened once again on the way back on the same stretch of freeway however this time it only happened once and this time it was clear and sunny. Any thoughts on what may have caused this and whether or not this is normal?

2: One morning when I started the car it was like it was on but pushing the gas pedal did nothing and it sounded like the engine had a little "cough". I simply pushed the start button to turn the car off and it did it again and again I pushed the start button to turn it off and then the third time the car started flawlessly. This was early in the morning after the car was parked outside overnight. This happened one other time after the car sat at the airport for a few days. Again these are the only two instances of this event.

3: Finally the "whoosh" noise that occurs from time to time is still there however both my wife and I heard it last night a few times with this being the first time hearing it outside of the morning and after 500 miles of driving the car. You may recall we discussed this as possible be something to do with the control bushings or whatever you call it but it does not affect the performance of the vehicle but will be one of those noises that at some point will reveal itself from where it is coming and what is causing it.

That's it for now. Hope everyone is feeling better.

Glenn


1) The system wants to make sure you get out, walk around and then get going again on the road. this is normal.

2) Would need to inspect the car for this concern to see if the fuel system computer recorded any issues

3) Would requests a test drive with a technician to hear this noise. would want to do this at the same time as we look at the fuel system

Im happy to hear that you love the car and the mileage was wonderful on your trip. Look forward to seeing you Glenn. Sorry I missed you last visit.

jakematic

I've had the ACC error 3 times in the last 4,000 miles.
It happened to me once on an 800 mile trip, and twice on short trips of ~15 miles.
Once it happened on a foggy/misty day which is understandable due to the light mist coming off the road - the others were in dry sunny conditions.

Their response about it wanting you to "get out and stretch your legs" is ludicrous in my opinion....

Haven't seen #2.

Is #3 right out of the gate ?
Reminds me of the infamous control arm bushing sound.
Mine has that, usually in the morning and seems temperature or time it's been sitting related.
Also pretty common on speed bumps or rough paving after parking.
I expected it to some degree on an 85K mile D3 but did a serious eye roll and cursing fit after hearing it on a brand new D4.

weth

This could be a clue. I do know the ACC needs to have a frame of reference and one thing that will cause it to lose a frame of reference is a featureless surrounding, i.e. flat desert. Basically, the radar is not getting any bounce back from anything, so the system does not know if there is a malfunction or there is just nothing out there to bounce off of.

See this Audi video at the 3:15 mark:

RL371

I'd also check and make sure the sensors are clean. After a long highway trip, the sensors could have mud/dirt on them, which will cause a fault.

Their answer to #1 is insane, but laughable.

blsching

This is so unexpected, it may in fact be true. Audi thinks of everything, like turning off the engine when you step out, just in case!

derfA8L

Had a similar ACC malfunction back a few months ago on my 2011 A8. Happened 2 times, both at night after driving close to 2 hours, and both times at just about the same location on the highway (exactly 1 week apart). First occurrence was in misty weather conditions, and corrected itself after about 15 minutes; the second time weather was clear and, again, came back on line after about 15 minutes. Dealer found a fault code for the R/H side radar camera/sensor---Audi Tech Support recommended re-alignment of all radar sensors before authorizing replacement of the fault-coded radar sensor. The re-alignment process takes a few hours on the 4-wheel alignment machine (they also found the car to be slightly out of alignment). Haven't had the problem re-occur...yet. Also had the ACC shut down on me one time about a year ago while driving into a low sunset---direct sun glare is a known factor causing havoc on an ACC system.

The comment about the ACC system's stoppage to counter driver fatigue is really ludicrous IMO. Just have them check for faults in the system, and go from there. Can't comment on issue #2, but for #3 I have had a front-end "whoop" on my car since the beginning, when first starting out after the car has been sitting overnight when temps dip below 40/45 degrees---typically happens when going over a road bump or dip. It's probably just the front stabilizer bushings that are cold and need to warm up; doubt there's anything wrong with them.