If you are asking me, that car never did it again in the approx 18 more months I kept it and then I turned it back in at lease end, getting a 2020.

 

That's EXACTLY what my 2018 S63 has done to me twice. Once was at highway speed and once in a 45mph zone. It's extremely unsafe. I've told anyone that will listen to me that the system that's supposed to "assist" me in the case of an actual accident is ultimately going to CAUSE an accident.

It's violent/abrupt when it happens and if you don't either mash the go pedal as fast as you can, or swerve back into your lane, you're going to get rear-ended- and for any eye witness it would "appear" that you could have done it intentionally! They'd see you change lanes and then for no reason what so ever jam your brakes on. It's a serious hazard and I cannot believe that MB has this in place as a "safety feature".

I THINK you can actually turn the function off, but then every time you key cycle the car it defaults back to "on". Can anyone confirm this? Is there a way to turn it off, completely?

 

No it cannot be turned off at all.

 

Wait, so are you saying that when you set it to Early, Medium, Late or Off in Vehicle > Assistance > Active Brake Assist it sets it back to On after you restart the car? Sounds like we need another ODB module then to keep the setting persistent (after the eco start/stop disable module). I guess also turn off Lane Keep Assist so it doesn't brake on certain lane markings.

 

I guess it depends to be honest, maybe the pre-facelift W222 doesn't let you turn it off or it might be a setting in the driver's display instead of the infotainment screen.

 

Yes. That's 100% what it does. So, yes, it CAN be turned off, but has to be done every single time you turn the car on. I'm only speaking for my car obviously- not sure on the others.

 

Not quite sure why they set it to that to be honest, I guess because it is a "safety feature" and MB wants the driver and passengers "protected" incase they forgot to turn it back on, even though it is proven to be accident inducing at times.

 

I don't recall hearing stories of accidents actually being caused by this technology.

 

I've had my 2021 GLA for less than 2k miles; it's already been in the shop for two weeks after which I was told they either couldn't replicate my problems or the systems were functioning as designed.
Last night I was in light suburban traffic, at least 50 feet from the car ahead, and the brakes slammed on for an instant. Very scary; lucky no one was tailgating me. I see that this problem has been described in this form many times, dating back more than a decade. Do anybody know what's happening? Has MB acknowledged it in any way? Should it go back into the shop? Any info would be appreciated.

 

My suggestion is to file a complaint with the NTHSA. Maybe if enough people complain they will open a case. Otherwise MB does not recognize this is a problem. I no longer own this car. We took a loss but I am not going to drive in fear of it spontaneously engaging again.

 

I have a friend that had a S550 pre-facelift (forgot the year) here in Canada that got rear ended because of such malfunction, although I wasn't in the car, I don't see why he would lie to me as he likes Mercedes-Benz and had since moved on to a 2019 S560 4MATIC with zero issues. However, the driver at the rear was following too close I would believe which made the accident possible in the first place. Likely, he wasn't even injured. I also never heard of such an issue on the news from any car brands as well just like you so the technology has more benefits than drawbacks and I don't believe MB's active brake assist caused any death so far (at least I hope and not just not reported by the news). So I believe the malfunction was a one off. The most common so far is it (the system) giving people mini heart attacks when it malfunctions.

 

I am sure all of you love your cars despite these glitches now and there, no car is perfect after all. Don't be this guy (although for a different issue) : https://www.autoblog.com/2015/09/14/...des-s63-video/

 

But thats a very unusual situation. How many accidents have been prevented by this technology? Its a lot.

Do you know who they deemed at fault for that accident?

 

Mhmm I agree with you, I am glad that it prevented many accidents too. Yes. He said the driver in the rear accused him for brake checking but thankfully my friend had both front and rear cams installed that recorded the whole thing, the insurance company was able to determine that the driver in the rear was following too close and therefore was deemed at fault. It was likely that both cars were assessed to come to a final conclusion because I didn't understand how dashcam footage is able to determine such a thing. I asked my friend and he didn't have a clue either, well either way my friend has recovered from such experience and it didn't discouraged him from getting another MB so there is that.

Maybe the insurance company was able to pull data from both vehicles? I am not sure. What do you think?

 

Typically the car in the rear is always at fault, because they should always be able to react to what the car in front does unless they are following too close, I was interested to hear if they would blame it on him since he had a vehicle malfunction.

 

I am not sure if he told the insurance company that his car suddenly braked causing the collision, I think he just gave them the footage and the insurance adjuster just analyzed the damages on both cars and called it a day. If the insurance company had the data from the vehicle on how it suddenly applied brakes then it might had been a different story but most insurance companies don't go through that hassle of pulling the data unless they are suspicious I think?
If they had done that, my friend could had provided proof that the brakes were checked at the dealership from last service (he has PPM) and that all recalls (especially safety ones) are addressed. Unless there is more to it, I don't quite know how the insurance works so that is just my assumption on what will happen.

 

Either way, and thank goodness nobody was hurt, the fact remains that unexpected sudden braking was responsible and remains a known problem for this vehicle. It's possible that so few reports of injury are due to the fact that it happens so quickly and there's no record of it, making it difficult to report.
As for the justification that it has prevented many accidents, that's small comfort to those of us who have experienced it and now drive in constant fear of it happening again. As for the explanation of tailgating, suppose there had been no tailgating but the road conditions had been slick and icy? Likely to be the same outcome.
Yesterday I filed a complaint with the NHTSA. That, along with my call to the dealer, at least puts me on record as making the problem known to authorities. If it happens again and there are damages, that should bolster my claims.

 

I've experienced it multiple times in different cars. I still believe the technology does way more good than harm.

Like I said, this is not a Mercedes thing. I experienced it in my Lexus and a Jeep Grand Cherokee.

 

I just purchased a 2019 S63 with 9000 miles on the clock and it behaved like this twice on the freeway last night. Going to take it to the dealer next week to see if they can check everything. Very scary to say the least.

 

I would also call and write a letter to MBUSA. The more they hear about this issue, the sooner they will get the incentive to try and find out why these events occur and what needs to be modified to prevent future occurrences. Your comment about such an occurrence on ice is truly concerning and potentially deadly.

 

I went to the MB Dealer in Bellevue, WA today and the SA basically told me it either works or it doesn't. He also suggested I turn it off in the city, when dark or when it is raining hard, which is basically all the time in the winter here. I am going to just turn all that crap off and only use it when I am out on the open road. If it happens again I am going to start logging it and if they cannot fix it I will look at next steps. Pretty amazing that they have a design flaw like this and no one has been hurt or injured with this Jekyll and Hyde feature set.

 

To be fair, I have had the exact same thing happen in two other manufacturer's vehicles...

 

Why did the SA suggest you to turn brake assist or collision prevention assist off at dark? The system operates on radars that see equally well (or poorly) at day and at night. Did the SA assume it worked with the camera? I guess Tesla does (not saying Tesla would not work well).

If the system has a design flaw, a bug, there is no way to claim it either works or it doesn't. Assuming the "it doesn't" means active brakes do not activate. Otherwise obvious, something either works or is broken and needs to be fixed.

 

only had 1 experience with this malfunction. one late night I was making a right turn onto a street with trees lining both sides of the street on a four-lane street with street lamps also on both sides of the street and my car just emergency broke from 15mph to 0 with not a single car to be seen. On the next service, I told my service advisor about this and they came back with "could not duplicate issue". They did a software update and hasn't happened since (been 3months now).

 

It doesn't have to be a car triggering collision preventive actions. However if it was a 4-lane street and no traffic light poles or anything like that at the centre of the street, the car should not panic from hitting those. I often get a warning from a traffic sign at the centre of the road when the road is bending. The car is not aware that I'll be turning soon a bit and avoiding the sign. This is an early warning and brakes would only be applied if I continued to drive towards the sign another second or two. Your scenario sounds like "a real mistake".