2015 with about 65k miles.
No known accidents, we are the second owner and we have had it since Jun 2019.

The Audi Assist started developing, occasionally, a problem with being active.
There were days it would work, then it would not... and at some point it stopped altogether.
Whenever I press the button, it says Audi Assist Fault (or something like that).

I spoke to my dealer who said they may take a look at it, but it would be $390 cost. Since I needed a 4-wheel alignment, I was informed that it is done at the same time. So in theory I spend $195 on the alignment and extra $195 for calibration as alignment is half way there to get the calibration done.
So they say the angles are off and they will correct them.

Few days later I get a text saying the module does not respond and it is becoming $1'200 job. I am like - nah, I will pass.

I am told the passenger side is not "shaking hands". I am like - yeah, possible, post Covid behaviour.

All in all - I was given a part number for the module - 8T0907568B.
It seems eBay has used ones very cheap. Worth trying, I think...

But before I go there - any suggestions? Could it be wiring? Something broken, loose?

Also, am I right - this module is in the corner of the rear bumper?

By the way - the backup, and front sensors, work fine No problems there. But I think those are completely separate.

And finally - does it sound right that they see angles are off, but cannot program?

 

The side assist aka blind spot assist aka lane change assist system uses two radar units mounted at the corners of the rear bumper cover. Yeah, one of mine is dead now too (though it took 14 years). These have no interaction with the backup camera or park distance sensors (which are ultrasonic).

I would never go to the dealership for "what's wrong". I own VCDS and can scan my car when there's a concern and get some idea of what's going on. Rather than let the dealership make up whatever because they know I know nothing.

If the unit is dead, it'll need replacement. If it's replaced, it'll need calibration. But there's no point calibrating it if the system has issues; they have to be fixed first. And the system only needs recalibration if the rear bumper cover has been dismounted. It's a radar system, so it's calibration is independent of any of the other systems. But I could see them setting up the system at the alignment station.

Very much could be wiring or fuses. All that would need to be validated (I would think they would have done so before saying you need a new module), or just swap the unit and see what happens. The p/n are reversed for the Q5 compared to the A4/A5, though the p/n are the same for the master and slave. 568B is the slave unit (J770), on the right on a Q5, on the left on my A4. https://www.ilcats.ru/audi/?function...35&language=en

The car talks to the J769 (566B master unit), the J769 has a dedicated CAN bus to the J770. Without a scan, it's speculation to what they are saying. I assume the J769 is saying "can't talk to the J770". Maybe a power/ground issue for the J770, maybe a wire issue with the dedicated CAN lines, maybe the J770 has simply checked out.

 

My wife was in an accident last year and the dealer told me the module was bad. I have VCDS and checked the angular deviations and proved that are wrong and don’t know what they are talking about. They recalibrated and it all worked and had to stick their foot in their mouth for insisting the module was bad (sad people working at a dealer can be this clueless)

this was the second time I had it calibrated and fixed in the last five years and now it’s out of calibration again. Only thing on my car that doesn’t work 100% and my advice is just to ignore it, it’s a PITA and honestly I can check my own blind spot

 

Thanks for the replies.

To give more details about the visit.
I hit a pothole and it damages wheels (but not the tires...). Also rear right wheel bearing failed (66k miles). When I asked about the noise and cost to fix - I was quoted above $800, if that is the bearing. Hence it went trough the insurance...
However, the dealership said - they will not take money from insurance, they want me to pay and be reimbursed from insurer.
So I did it myself (bearing) addressed the bent wheels with local shop. One had to be purchased "new to me" and in the end I had to get the alignment checked. Despite so hard hit it was pretty much spot on. I am very pleased with the Audi suspension durability.

Anyway, back to the Audi Assist.

I wonder if my hitch installation could have messed it up a bit... but the system worked afterwards without any problem.
I will need to check the wiring and the module. I will remove the bumper again to see the module itself and wires to it.

As for VCDS.

I have one although I have not started using it, to be honest. OBDeleven did almost everything I needed.
Now, can you test if the module is fully functional using VCDS?

They (dealer) claim drivers side works, while passengers does not.
Would the faulty module result in some sort of codes which OBDeleven report?
The only code I see is

C1115F0
Lane chance assistance control module 2
Automatic calibration not possible

 

That error message indicates the angular deviation is too high. I have a thread here explaining it and showing it in VCDS. If the angular deviation for either side exceeds ~+/-7 degrees it can’t auto calibrate. A pot hole or hitch, anything that slightly changes the angle of the bumper will mess it up. Like I said I’m leaving mine as is this time, only thing not working on my car and doesn’t bother me a single bit

 

Could you point me to it?
I looked into your profile, but the thread was not listed... or the name was different than I thought it would be.

I kind of vaguely remember 7 degrees limit from somewhere...

 

I am away from the computer but read this thread I know I show it here….

https://www.audiworld.com/forums/q5-.../#post25625750

 

I do not think I provided an update.

Turns out the dealer was right. It was indeed the module. I got a used one from eBay (some German auto parts "recycler"...). Apparently originated from Macan, like it made any difference. As long as the part number was correct, it should work.

After plugging it in and checking with VCDS, it turned out to still have the same codes plus some more. No driving helped.
I went back and they coded it in no problem this time. The system worked back again.
And they said it took the values no problem.

So instead of a new 1200 USD part, I got it used for 30 USD.

And few months later the car was sold.
It was a very fine car. Really good one.

Thanks everyone for help.

 

Key identity items needed for a suitable replacement must be the same

Example of an incompatible replacement