I did a lot of research into pre-sense before I bought my S4. I drive pretty aggressive sometimes, never had it come on, it's only come on during situations when it was needed like 3 times now. I saw a few youtube videos though of someone pulling into a turn lane and the car violently stopped because of pre-sense. I think it could be a glitch or something.

No glitch. It's happening unnecessarily too often to all of us. In 15 months of ownership, I have had a dozen false pre sense interventions. Every time it feels like I hit something and there was nothing anywhere within half a car's length. I am now starting to question if my reflexes are weakening with age because of this stupid system that doesn't work right. I hope Audi is working on improving it on newer models.

It definitely doesn’t happen to all of us; coming on 2 years with the S4

I've had 2 incidents where the car actually applied the brakes in 2+ years. Once on some switchbacks where there was no danger of a collision, but due to the curves the car was pointed at a cyclist coming in the opposite direction. I got a short pulse of the brakes until the cyclist passed.

Another time when backing out of a parking spot the rear camera saw a pedestrian that I had already seen and wasn't in danger as I slowly pulled out, but the brakes locked up hard.

If we count the pre-sense warning chime, that happens all the time, even though there was never a situation where I needed the warning.

All in all I'd rather have the safety feature and put up with some minor annoyances than not. I'm sure it will improve in future generations.

Thank you for that good and useful information.

This, "The system likely beat you, even if only by a fraction, as it typically will not engage if you already had your foot on the brake, and were braking adequately. Brake assist will cut in if the system still thinks you are going to crash - it uses the ESC system to individually control each brake to minimise a chance of skidding and to encourage / enable the driver to take some steering action to avoid a crash. Sounds a little like what you experienced. The most likely cause for weird steering/ brake behaviour would typically come from using a non-OEM wheel offset. Typically a lower offset as that moves the scrub radius in the wrong direction for an AWD car, but Audis are relatively tolerant."

Therein lies the problem. I'm sure the system braking beat me, per it's calculations. That was not the problem, that it applied the brakes before me. The problem is what happened AFTER the car's system applied the brakes, and then me applying the brake pedal at nearly the same time.
The realty is my S4 pulled heavily to the left and then right. The road surface was warm and dry. I made the subtlest of steering corrections, but only because of the system causing the left and then right pull. That should not have happened in the first place.
If the system beats me to the brake pedal, then it should be programmed well enough to give me brake control back as I am on the brake.
And, if the system "thought" my braking was not heavy enough, well that too is a problem, because I was easily able to slow down and still have about 3 car lengths from the car in front.
To me, it seems the system took too much time to "figure out" what is happening, as it engaged the brakes, then I engaged the pedal. The split second overlap could have caused the system to keep it's brake pressure on as I was modulating the brake pedal. And, it overcompensated causing an initial front left drive, with a quick recovery and then a quick pull to the right.
Still, that is a problem, as that is NOT what a seasoned driver is expecting.
I've been driving for nearly 40 years, and to me, that whole event was WRONG, poorly done and poorly executed by Audi's system.

If a vehicles "safety" systems need to take over, then take over until the "threat" is mitigated.
In my experience the system fooled itself and me, as this happened very very quickly.
Still, that should NOT have happened, as it only takes a split second for something to go wrong at higher speeds.

Understanding how the system "should" work, does not mean that it works well in every situation.
If I were a novice driver I may have had an accident. However, I kept brake pressure and modulated to, HOPEFULLY, bring my speed down and to not push too hard and force my car left into the concrete divider or the semi on my right.

I've owned one Audi A4, a 2006 model year, and then 3 BMWs after that. My last two BMWs, 335i Msport and 340i Msport, those cars never exhibited the type of system disconnected feeling.
My S4 is an ok sport sedan, but I'm finding something not right with this "auto avoidance" system.

One thing I hope will mitigate this from happening again is that I set the pre-sense to "late". It was set to "early" when that event happened.

Also, I have the base/basic system in my S4. I did not add any "safety" features above or beyond what comes as OEM on the S4.
So, I don't know what, if any, differences there are.

Cool! I figured the new models had a newer system but thanks for the explanation. I'm currently driving a S5 SB but I live in Canada and we don't get AEB as standard. May look into a S6/S7 in a few years with these upgraded safety features.

These stories are hilarious. I disabled my pre-sence after 100 miles. I want to drive my car. Not ready for a Tesla yet..

You do it every time you get in the car? I've had 3 or 4 instances where it has kicked in, all on slow maneuvers backing up.. Half of those times, were because it picked up another vehicle passing by that was on an adjacent roadway to a parking lot.. The other times it must have seen a ghost on a bicycle. I do get the front parking system warning sometimes when in back to back traffic or when its snowing.

Disabled permanently? If so, do tell how, please.

This is easily done in OBD11. Haven't tried it myself but there are PLENTY of pre sense settings. It may impact active cruise control and such though. No idea, haven't tried it myself.

That said what are you people doing? Eating hot dogs and drinking coffee while the car is in motion? That's... Not a great idea.

Plus all this system has to do is save you once for you to thank it.