JShepFL

Anyone else seeing this? The car chimes and says ACC and Brake Assist not available. Seems to be 1/2 the time. Sometimes it stays on for the duration of my trip and others it comes back on during the drive. Not sure if this is normal. Would love to hear what others are seeing.

chicagoA6

Only time I lose functionality is when traveling in tunnels or areas with intermittent light. Then once in the open all functionality is restored within seconds.

I would make sure your sensors are clean and if that doesn't help I would ask the dealer.

AudioBear

This has happened to my 2014 A6 Prestige TDI about a half a dozen times; usually near the end of a long day of driving. The dealer found no codes and speculated it was 1) a dirty sensor, or 2) conditions that triggered it to turn off. Those could be a barren area with no traffic or targets but this was not the case for most of the events I experienced. In my case it turns off and 5 to 20 min later it will turn back on. It may turn on and off several times before it just resumes working. I have made sure the sensor area behind the mirror, the Night Vision sensor, and the two sensors at the lower left and right of the front bumper were clean--in my case cleaning the sensors did nothing. I can also drive all day and never have this happen. That somewhat shoots my theory about it being overheating of some circuitry. I have not noted outside temperature when this happens and don't know if there's a correlation but it has always been in the summer when I drive a lot. It's so infrequent, there is no way to reproduce it for the dealer. I haven't pressed him to fix it because in my case it happens so infrequently. I have accepted it as just another Audi quirk.

It sounds like you have a similar problem but it happens at much higher frequency so you need to get it fixed. There may be some mention of this elsewhere in the forums but I can't remember what I searched to find it.

I'd be taking it to the dealer and insisting that they fix it. The condition you describe is unacceptable. The dealer will tell you that he can't pull down an error code. Don't accept that as a reason not to do anything.

JShepFL

Well at least I know it's not just me. I am pretty much a car wash freak so they are kept pretty clean. I live on the west coast of Florida and our highways have good markings on them. I take the same highway to work and sometimes it is fine and other days it isn't and the conditions are the same. Baffles me. Off to the dealer I guess.

fkaufman

Have not seen this one in my A7 in 3 years of driving.

Suggestion: Take a picture of the dash panel when the warning is on, if you can. Having taken pictures of the error messages helped me to get intermittent issues fixed, when a simple verbal complaint would have been taken much more lightly.

MichaelChicago

I had an intermittent problem early on with my 2012 A7 just like what you're describing. Took the dealer a while to diagnose a faulty sensor, which they replaced under warranty, and all is fine now. It still happens for very short periods of time when I exit my parking structure downtown, but I think it's due to interference of some kind coming from a very high security building adjacent to the parking structure. It clears up on its own as soon as I'm out and on the road.

JShepFL

It got to the point that ACC and Brake Assist were inop 90% of the time when I finally took it in to the dealership. After 2 days of diagnosis and calls to Audi they are replacing the NAV antenna. It was not recognizing the Brake Assist. Who can figure how cars features are connected these days. Fingers crossed. Hope it helps in future thread searches.