SCARY Active Brake Assist malfunction?
 

My wife and I were up in Montecito this week, which is about a three hour drive from our home. While driving our 2018 S560 down a two lane, residential highway, going maybe 35 or 40mph, the car suddenly and totally unexpectedly slammed on the brakes for an instant. I had been looking straight ahead at the time and had not seen anything cross our path, such as a squirrel, cat, bird, etc. In addition, the road was straight, level and there were no vehicles in front of me or approaching from the opposite direction. There were trees and tall hedges on either side of the road, but they were at least ten or twenty feet away on either side.

The warning tone sounded, our seatbelts cinched tightly and the car braked so strongly that you could feel the ABS kick in. It all happened in an instant and then it was over. I believe that I may have tromped on the brake pedal as well, just as a reflex, but it all happened so fast, that I really don’t remember all the details. I looked to see if we had run over anything, but there was nothing. We continued about two miles to our destination, where I examined the car, but there was no sign of anything out of the ordinary. Only a few, small bugs on the plastic Distronic sensor.

I have to tell you that my wife screamed and this event scared the hell out of me. The car has operated perfectly since this happened and I used Distronic most of the way on our drive home. Did the system just hiccup or??? Has anyone else ever experienced this? I plan on taking the car into the dealer this week and having it checked out. Scary!

Might be a good idea to take the car in this next week and have the dealership check it out on the computer. Mercedes needs to know this has happened. It would also be a good idea to mention them not buying parts from Tesla. I am of the generation that appreciates some of the new computerized car functions but really don’t like them just for the reason that they sometimes go crazy. Remember Windows 95?

My 2015 S-600 (somewhat) often beeps at stop lights, when I am already stopped, as if something was running up to the front bumper.
Never seen a critter yet.....

Streamliner......funny that you should bring this up, since I have had more than once a similar experience. My '15 S550 has done the exact same thing but seems to think that I have crossed a line on the left or right....but I have not. The car brakes suddenly and then releases just as suddenly but there is a bright red hwy line pictured in the dash in front of me, showing the line that I supposedly crossed. It is scary when you really don't expect it. I wonder now if I should bring this up with the dealer ?

Take the car into the dealer, they will ( or should ) scan for stored code. As your purchasing dealer do a good will Disctronic calibration.

I've read instances of this happening in the 213 forum as well. Same issue of nothing in the way/on the road, sudden braking. No real answers.

wow scary...

I believe what you are describing is Active Lane Keeping Assist, and it sounds as though your system is working properly. Is it braking on just one side, to pull the car to one side?

https://cimg5.ibsrv.net/gimg/www.mbw...d79bb262c.jpeg

I bet if you were travelling alone this post would not even exist :)

I have just turned off this safety feature as the same happened to me 2-3 times for no real / useful reason.

Well, regarding me, that would be incorrect and there is no way I’m shutting down any of the safety systems. One of the main reasons I drive MB cars, is due to the Active Brake Assist and related features. I feel that this was most likely just a glitch that should be cleared up with a reboot of the system by the dealer. I just leased a new SL450. I might have actually gone for a Ferrari Portofino instead, if the company had a full package of electronic safety measures available on their cars, but they have virtually none.

I really, really despise that feature, I resent having a censor sitting on my shoulder (or driver ed teacher slamming on the brakes when he “thinks” I would do something bad).
I also had an extremely dangerous moment when tried to pass a slow semi hogging the left lane but had to get close to a bus on the right lane to squeeze through the gap.
My S560 loaner slammed on the brakes at the same moment I was getting in front of the semi, only my instant turn back to my lane prevented me from being slammed from behind.
My stomach was in my throat and heartbeat in mid 100s.
Now, first thing I do, even before clicking the belt on, I turn the damn thing off.
When I pick up the S63, I want to figure out how to get rid of it permanently.

That's why I prefer having the least technological assistance in the way of active intervention as possible, a warning chime is ok but in certain situations these features may actually cause accidents.

Just wow.

Perhaps I should be more specific: I love the Active Brake Assist, when it alerts me that I am approaching the car in front of me at too great of a speed and the tone sounds. Invariably, this is due to the car in front of me hitting their brakes, along with the possibility that I was momentarily distracted by looking at the Nav, audio, glancing to the side, etc. I cannot recall ever actually having the car initiate braking on its own, because I am always on top of the situation and brake myself.

I’m sure we have all experienced situations in the past, usually in city driving, when the car in front jams on the brakes while we are distracted. In most all cases, we do not hit the car, but just about have a heart attack in the process. ABA has virtually done away with such experiences. In addition, in stop & go traffic, to make the ride even less stressful, I use Distronic Plus, which gives me an extra set of eyes, while braking and accelerating my car as needed. I can understand why some may not like these features, but my aggressive driving days are well behind me and I find these systems to be absolutely invaluable. I look forward to their further sophistication and refinement and believe that every new car sold in America should be so equipped.

The real prblm is when people solely rely on these systems and dont actually know how to drive as we experience here in Nyc.They do not most of the time respond as advertised. Nothing will replace an experienced good driver as road conditions cannot be programmed into a computer.

Absolutely! These systems are for driver ASSISTANCE, not driver replacement.

I still drive in a aggressive mode most of the time, usually pressed for time, stressed out and not having necessary patience to deal with lane hoggers, people out for a leisurely cruise, etc.
These nannies are truly helping and make driving safer for most drivers and most situations, I really have nothing against cars being equipped with them but for me personally, they end up being dangerous and additional impediment, take away my confidence in my own car, since I never know what it may do when I don’ expect it.
I only dislike being forced to have them by default, wish there was an option to disable them permanently and have them back only when manually switching them back on (when I am not in a hurry and I want a “leisurely cruise” myself).
Something like ABS on/off switch in the Audi 200 Quattro back in 1989 that I used to have.

That's scary indeed, the more I read such messages the more I like to rely on driving the cars myself .I think Airbus's computers must be more reliable than those of Teutonic cars

I have a gen 3 viper, its has abs. thats it. smash the gas and a sideways you will go..make sure u know how to steer.

As E Musk has stated all this driver tech will only be faultless when these cars can talk to each other. It will either be by a third party they all accept or by Tesla producing so many cars that the odds would be with you. Basically take the above scenario with the truck, the three vehicles would communicate with each other and stop and steer their way out of it. The truck would have known you were stopping faster than the driver would see it. When it is one vehicle with the tech it can't be fool proof as the other cars cant react as your is.

There is a patch of road I drive everyday and for some odd reason the lane assist locks up very aggressively for no reason at all. I shut it off as it is annoying and it does almost cause accidents as people think your swerving away from something. I think in a away they make us lazy and you get comfortable relying on a system that isn't 100% and that cost down on your reaction time.

That’s how it used to be, drivers had to learn how to drive, cars didn’t drive for them and did not fix their mistakes like today.
With all the nannies in new cars today, I am amazed there are still so many accidents, people just get stupider and stupider.
As for your Viper, I know exactly what you are talking about, owned a Carrera GT and put 7k of maximum fun miles on that car.
I am stupid too, for selling that thing after all.

people are getting stupider, most learned how to drive on cars w no safety systems like this in place, figured out how to drive in snow ice etc w no fancy setting. Actually could parallel park..Now people drive cars that do it for them. Funny Im in real estate was showing a house a few weeks ago and was blocking the empty house driveway I was showing. 10 mins in I hear a blarring horn... I walk outside, neighbor wanted me to move my car bc she didnt know how to angle her... u guessed it s550 into her driveway. I obliged and moved the car forward 6-7 feet and she still couldnt figure out the angle.( with my car 10 ft away from her driveway) No idea how she couldnt figure it out but by the condition of her car and the beat to hell bumpers I just walked away and let her deal w her own issues.

This really cannot be. According to Wolfman, these S series cars never have problems. ;)

You maybe happy, or perhaps worried about the fact that the hardware/software modules for active brake assist are the exact same as in your E-Class coupe. Not model specific..
Always appreciate your valuable contributions of course ;)

To Streamliner; this is something that should be checked out at the dealer. From the sounds of it, it's not a full stop vehicle avoidance scenario but a hard slow down which is a bit less dramatic (unless someone rear-ends you of course). Scary either way. Active Brake Assist works on a hardware combination using camera, radar and vehicle data to determine braking actions, so hopefully there are some stored codes...

When driving expediently in traffic these warning sounds and set belt pulls are nothing rare; aggressive driving on the track will do the same but not an open road occurrence. Keep us posted!

Not having an E class coupe, yeah, not worried one bit. ;) Even if I did. Regardless, haven't heard this happening on any new E class model(s). But then again, I never made the claim of superiority of lack of S class problems as you have; I've spoken to the equality among models instead.