ACC and Brake Guard Unavailable

[netviper]

Hi All,

My 2015 S6 has a warning says "ACC and Brake Guard Unavailable". I took it to the dealer and they said it is because my rotors and brake pads are warn down and want $1400 to replace them.

I called another audi dealer and they said they had never heard of that message being triggered by that.

I have about 34,000 miles on the car.

Anyone had experience with that?

Also, looks like I can buy aftermarket rotors and pads for less than 1/2 of what they want. Anyone done that?

Thanks,

[ryanwerling78]

Very interested to see what end result is. I recently paid the dealer $470 to recalibrate the radar sensors on my A6. Which did not fix the issue.

Makes sense that brakes could cause ACC to not work.

Are you under warranty? Did they give the brake pads/rotors as a definitive solution?


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[netviper]

Very interested to see what end result is. I recently paid the dealer $470 to recalibrate the radar sensors on my A6. Which did not fix the issue.

Makes sense that brakes could cause ACC to not work.

Are you under warranty? Did they give the brake pads/rotors as a definitive solution?


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I'm under warranty. They said that will fix it. Nobody else seems to think it will or is even related. I've searched several threads and that is never mentioned once.

[gdawg'05a4]

Is your brake pad warning light on? If not, I don't see how it's connected. I doubt ACC/Braking Guard is monitoring the brake pad thickness. If the light is on then I could see the system being disabled with the pads at the wear limit. Did they scan the car for DTCs (errors) with ACC and Braking Guard?

[p3u]

Bullshit. They are saying that because they get paid out for the warranty work. Brake rotors and pads have nothing to do with the system being unavailable.

[shirwin]

I got this message twice in my 3 years owning my S6. On both occasions I wiped the lenses with a damp cloth and it worked again

[netviper]

I got this message twice in my 3 years owning my S6. On both occasions I wiped the lenses with a damp cloth and it worked again

I cleaned the car pretty well hoping that would fix it. It did not. :(

[Frenetic]

Yep, I got this right after I waxed my car with less than 300 miles on it. Freaked me out. Apparently I had some almost invisible wax residue on one of the lenses or sensors. I’m not sure which as I couldn’t see anything, but I wiped, very carefully, the two fake fog light lenses and the smaller sensors and the warning went away.

I’m really mindful of these now whenever I detail my car. Don’t want to scratch or scuff them.


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[netviper]

Yep, I got this right after I waxed my car with less than 300 miles on it. Freaked me out. Apparently I had some almost invisible wax residue on one of the lenses or sensors. I’m not sure which as I couldn’t see anything, but I wiped, very carefully, the two fake fog light lenses and the smaller sensors and the warning went away.

I’m really mindful of these now whenever I detail my car. Don’t want to scratch or scuff them.


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I can try again.

[netviper]

OK, so they called and said there was a misunderstanding and the two are unrelated. Code was cleared and didn't come back.

[dc2002]

I got this message twice in my 3 years owning my S6. On both occasions I wiped the lenses with a damp cloth and it worked again

+1 Happened to me once in the year i have owned my car - car was pretty dirty, gave it a good wash and error went away.

One time my mirror alerts stopped working, cant remember if I had any other Cluster messages but come to find out I accidentally hit the button up on the door and turned the system off...stupid me...lol

[car]

There is an engine software update for this. I have had the same issue twice and will be getting this loaded at my 25,000 service.

Technical Service Bulletin Transaction No.:*2046232/4

01 Start-stop system error, A/C Inop, MIL light on (DTC P011600, P017B00,
and/or P011F00)

Release date:*Jul 27, 2017

[cdubya19]

I've had this happen to me once when the car was really dirty. Clean the 2 fake fog lights and the windshield where the rear view mirror is. I believe there's another camera there.

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[AUDIofil]

As long as you don't have warning light about your brake pads being worn out, it's not related to brakes. It would be problem with either ultrasonic parking sensors or ACC radar sensors.
I had this message pop out when driving in very heavy rain. Another time on my Q5 when driving in snow blizzard with wet snow, there was accumulation of snow on bumpers and Side Assist got temporarily disabled.

[scottfree.sp]

I got this message about a month after owning my car after going through a touch-less car wash, took it into the dealership and the module had to be replaced, It just randomly went bad…They said had nothing to do with the car wash but it was very odd that I was on the freeway with it working just fine before wash, then right after car wash as soon as hop back on the freeway and try to enable ACC I got the message.

[netviper]

Latest update.

They said the code was cleared, went to pick it up and code was still there. Now they are saying its misaligned and its $380 to fix it and not covered under warranty. Anyone have this issue while under warranty?

[FourRingThing]

I had this alarm and they told me the same that I needed the alignment which is not covered by warranty. It turned out that one of the sensors (looks like fog light) came loose from its mount and just need to be snapped back in and all was well.

I replaced my rotors with the drilled and slotted ones from ECS they have been great and used Akibono ceramic pads they are the only way to go no brake dust and they will not eat the rotors like the stock units and will last much longer.

[jrsAudiA6]

Since I had put an after market suspension on my car the ACC as needed an alignment according the dealer and when looking at VCDS. I have not had the alignment done and yet it still works to my satisfaction. So, I seriously doubt that an ACC alignment will correct your problem. Since this dealership service department seems to be shooting in the dark for a solution you might want to take it to another dealer or get AoA involved.

[Fast4DR S6]

Hell my ACC & Brake Guard has not worked in the last 2yrs! My driving patterns are such that I never used it when it was working.

[ryanwerling78]

As others have said I highly doubt the alignment will fix the issue. From the hundreds of threads I have reviewed it seems to be either bad wiring, dirty sensors, or rarely bad sensor.




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[dc2002]

Someone posted a diy alignment procedure in the c7 a6 section of audiworld I remember seeing a while back. Didn't look too terrible iirc

[ryanwerling78]

I am extremely curious as to what the issue is. I have been without cruise control since August when I got my windshield replaced. After getting my windshield replaced my ACC and Brake Guard error came on. The installer I brought my car to originally got the wrong glass and still installed it. They also glued my image camera on (without my permission) instead of getting the correct windshield... So, I took the car to an Audi dealer to have them fix the issue. They said there is no correlation between the image sensor on windshield and ACC. The advisor said it only has to do with lane departure warning. (My car doesn't have that) I need cruise control so the dealer says my car needs a sensor alignment and it would be about $400. I drive 160 miles round trip to work 5 days a week so a car without cruise is worthless to me. I dumbly agree to have the alignment done thinking maybe there isn't a correlation between having my windshield done and my cruise control not working. I get a call two days later saying my car is ready for pick up. I get to the dealer pay my bill and get in my car only to find out the issue still is not fixed after playing phone tag with the advisor days prior to picking my car up I am furious and have not revisited the dealer. Highly considered disputing the charge with Amex.

[ryanwerling78]

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[jrsAudiA6]

I am extremely curious as to what the issue is. I have been without cruise control since August when I got my windshield replaced. After getting my windshield replaced my ACC and Brake Guard error came on. The installer I brought my car to originally got the wrong glass and still installed it. They also glued my image camera on (without my permission) instead of getting the correct windshield... So, I took the car to an Audi dealer to have them fix the issue. They said there is no correlation between the image sensor on windshield and ACC. The advisor said it only has to do with lane departure warning. (My car doesn't have that) I need cruise control so the dealer says my car needs a sensor alignment and it would be about $400. I drive 160 miles round trip to work 5 days a week so a car without cruise is worthless to me. I dumbly agree to have the alignment done thinking maybe there isn't a correlation between having my windshield done and my cruise control not working. I get a call two days later saying my car is ready for pick up. I get to the dealer pay my bill and get in my car only to find out the issue still is not fixed after playing phone tag with the advisor days prior to picking my car up I am furious and have not revisited the dealer. Highly considered disputing the charge with Amex.

That is a very unfortunate story. If it were me I would be on the phone to AoA customer support. I fairly certain that camera behind your windshield is integral part of the ACC, hence your problem since your windshield was replaced incorrectly.

[AUDIofil]

I am extremely curious as to what the issue is. I have been without cruise control since August when I got my windshield replaced. After getting my windshield replaced my ACC and Brake Guard error came on. The installer I brought my car to originally got the wrong glass and still installed it. They also glued my image camera on (without my permission) instead of getting the correct windshield... So, I took the car to an Audi dealer to have them fix the issue. They said there is no correlation between the image sensor on windshield and ACC. The advisor said it only has to do with lane departure warning. (My car doesn't have that) I need cruise control so the dealer says my car needs a sensor alignment and it would be about $400. I drive 160 miles round trip to work 5 days a week so a car without cruise is worthless to me. I dumbly agree to have the alignment done thinking maybe there isn't a correlation between having my windshield done and my cruise control not working. I get a call two days later saying my car is ready for pick up. I get to the dealer pay my bill and get in my car only to find out the issue still is not fixed after playing phone tag with the advisor days prior to picking my car up I am furious and have not revisited the dealer. Highly considered disputing the charge with Amex.

Audi ACC system needs input from 3 sources: ultrasonic parking sensors, radar sensors (mounted where fog lights usually are) and windshield camera. It use all 3 systems together to recognize and track obstacles, measure speed and distance. I think ACC and Active Lane Assist is always bundled together in one package since windshield camera is used in both systems, so since you have one, I think you should have the other too. Regardless, since you had windshield replaced, it's highly possible glass company damaged something in a process or installed new windshield in a way that it interferes with camera operation and therefore whole system is disabled.
I would say try to get your car scanned by someone with VAGCOM cable and see if there are any errors.

[ryanwerling78]

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[ryanwerling78]

Audi ACC system needs input from 3 sources: ultrasonic parking sensors, radar sensors (mounted where fog lights usually are) and windshield camera. It use all 3 systems together to recognize and track obstacles, measure speed and distance. I think ACC and Active Lane Assist is always bundled together in one package since windshield camera is used in both systems, so since you have one, I think you should have the other too. Regardless, since you had windshield replaced, it's highly possible glass company damaged something in a process or installed new windshield in a way that it interferes with camera operation and therefore whole system is disabled.
I would say try to get your car scanned by someone with VAGCOM cable and see if there are any errors.

Thank you for your reply. My service advisor told me it was only for lane departure warning. I attached a few photos from my code reader. I just want to go to dealer and glass installer with all possible information.




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[netviper]

My parking sensors work and the lane assist works, just the stupid ACC and brake control. Very annoying.

[ryanwerling78]

My parking sensors work and the lane assist works, just the stupid ACC and brake control. Very annoying.

Excuse my ignorance what does lane assist consist of? I get the notification when a car is next to me via the led on the mirror but when I swerve into the parallel lane nothing happens that I’m aware of.


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[netviper]

Excuse my ignorance what does lane assist consist of? I get the notification when a car is next to me via the led on the mirror but when I swerve into the parallel lane nothing happens that I’m aware of.


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Scans the road and keeps the car in between the lanes. You can take your hands off the wheel and it will track the lane, but it tells you to grab the wheel after 5 seconds or so or else it turns off.

[Yeoman]

Time to find a new dealer

[ryanwerling78]

Just heard back from the dealer. They read the car again and it would not take a calibration of sensors. They said when they reinstalled the windshield when they glued to bracket on it was not glued on straight so it will not work. They quoted $2000 for a new windshield install and calibration.

Talked to district manager of glass company and taking the car for them to see it tomorrow as the install location is under new management.

So looks like no matter what I’ll have to get another calibration done.








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[DaddyO]

I have the same issue with the side assist also being inop as well. 2017 S6 with 1500 miles. Not happy I'm already having problems with a brand new car. Car goes to dealer on Tues and will hopefully find out cause and get fixed then.

[DaddyO]

Got car back today. Bad lane change assist module. Dealer replaced and recalibrated lane assist and all is now OK. Service advisor said it's the first time he's seen this module fail. Hopefully this is an anomaly and not a portent of things to come....

[ryanwerling78]

Well, finally a half update the glass shop got a new windshield in from a different supplier. The new windshield will be installed this Tuesday than taken to the dealer soon after to have sensors recalibrated. I’ve already paid out of pocket once for a recalibration after the initial glass replacement. When the dealer told me my car was ready for pick up not fixed. I’m going to ask the dealer to do this calibration pro bono and have the glass shop pay me the $450 for the first calibration. I feel this is fair.


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[Packy]

Hi All,

My 2015 S6 has a warning says "ACC and Brake Guard Unavailable". I took it to the dealer and they said it is because my rotors and brake pads are warn down and want $1400 to replace them.

I called another audi dealer and they said they had never heard of that message being triggered by that.

I have about 34,000 miles on the car.

Anyone had experience with that?

Also, looks like I can buy aftermarket rotors and pads for less than 1/2 of what they want. Anyone done that?

Thanks,

Oh I've had that message quite a few times. Gotta love rats crawling into the wheel wells and chewing through the wires to the front sensors. Do you have them in your area?

[scottfree.sp]

My 16 ACC front module went bad after about four months of owning the car, and had to be replaced. I don't think it's the rotors brake pads because mine down to practically nothing and ACC works fine... getting brake pads rotors next week :).

[Packy]

My 16 ACC front module went bad after about four months of owning the car, and had to be replaced. I don't think it's the rotors brake pads because mine down to practically nothing and ACC works fine... getting brake pads rotors next week :).

If you haven't picked them yet, look into disc italia. I have them on my S6 and love them. If they make them for the A6 (if they aren't the same) you'll be good. The drilled and slotted rotors look kick ass also despite not really providing any benefit.

[Mwolf1034]

I am now dealing with this same issue. Have a 2012 A6 with Acc and braking guard. Had windshield replaced, first by aftermarket windshield. Had the Acc/brake guard unavailable come on, Safelite tried calibrating five times, took to Audi dealer, calibrated and came back with Acc/braking guard no sensor vision. Said camera hole too small on aftermarket windshield and should have OEM put in. Had OEM put in, calibrated by dealer again and warning is still on. They’re telling me it’s throwing a code for a faulty cruise control radar in passenger bumper. It’s never been impacted, and all systems worked perfectly fine the day before having the windshield replaced the first time. I highly doubt the radar is bad. Has to be some kind of wiring issue, or the camera in the rear view mirror housing is messed up. What was your solution to the problem?? Any help would be greatly appreciated as they want me to pay almost $4,000 for new radar - which was working fine before the first replacement. Cheers!

[jrsAudiA6]

It is possible for the radar sensor to have failed. I had my passenger side sensor fail, without any physical damage, a couple of years ago. The cost for a sensor from the dealer is around $2300. Yes they are expensive. I tried using a used sensor that bought off EBAY but the P/N was not an exact match but I thought if it works it certainly is a lot cheaper but it would not work because it could not be coded for my car. My dealer charged me $600 for the ACC alignment. So $4000 to replace one sensor and align is outrageous. As far as your windshield, it should have been replaced with an OEM originally. I had mine replaced just do to excessive pitting and Safelight replaced it with an OEM windshield. They never considered using an aftermarket windshield because of the camera.