Active braking assist - less sensitive on my new GLB?

[Digsy]

I'm now on my third MB car with Active Brake Assist. The first was a 2016 B Class, then a 2019 C Class and I just changed to a 2022 GLB with MBUX (the other two were Comand).

On the B and C I used to get the "first stage warning" for brake assist quite a lot (probably not something to be proud of). Generally when on my commute I would get flashes of the warning to back off a bit, especially when joining a queue of traffic. Also there were a couple of spots on country roads that I used a lot which would regularly fool the system into giving me the warning beep as well. A bush on a sharp corner, for example. The car never got as far as actually putting on the brakes, but I knew the system was working because of the warning lamp and the occasional "false alarm".

However, on the GLB the whole system seems much less sensitive. I have barely seen the warning lamp come on despite not really changing my driving style, and also the false alarms no longer happen. And this is with it set to "early", which I assume is the most sensitive setting.

So I am left wondering, is Active Brake Assist on later vehicles more "robust", just less sensitive, or is mine not actually working properly?

And yeah - I get it. The light shouldn't be coming on at all.

 

[Benz17]

Maybe your driving has improved. Just kidding.

Has it not come on at all, have you tested it, just to see that it’s functioning.

 

[Digsy]

I have tested it as far as I feel safe doing but only so far as to make the light come on. No flashing or beeping an certainly no actual braking. Even with my presumably terrible driving, I only had ABA actually kick in to stop the car once or twice in the last 6 years as far as I can recall.

The light does come on but nowhere near as "easily" as it did in my B or C. I would say that the detection distance is maybe 1.5x as far as it was previously, but that's a guess, and as I said that is on the most sensitive setting.

I feel like if I had it set to "late" then I would be inside the car in front's back seats before the brakes came on.

 

[Benz17]

My ABA has only kicked in once in 3 years of ownership, when it did felt a bit wired, thought I drove over something whilst it happened.

Can you not get it checked out by the dealer, and even ask them if you could drive another GLB if they have one just to compare if they all behave in similar fashion.

 

[Digsy]

Yes that's the next step. I only got the GLB a few days ago so I am still getting used to it. I did test drive one prior to buying but cannot recall how ABA behaved on that.

 

[Ron240]

I have had autonomous braking systems on a few cars over the years, the first one back in 2012 on a Ford Focus.
The only car that made me aware of its presence by warnings both audible and visual was on a 2017 Honda Civic and this could be annoying.
My current car (with MBUX) now and again the proximity warning will appear on the dashboard, but none of my cars have ever needed to apply the brakes.
To me this is one of those systems that I know is there but I forget about it and trust to do its thing should the need ever arise.

 

[Digsy]

Ron, on your MBUX car do you think the warning light comes on at a reasonable distance, ass opposed to too early or worryingly late?

 

[Botus]

On many cars (with Volvo bothering to tell us), the idea its is leaves things to the last possible minute, and makes its actual full on intervention scary - so we don't use it as a day to day alternative to driving properly ...whilst concentrating all the time...

after all the idea is to save lives, not reduce the sale of bumpers / new cars

my 2006 S class has a beep from its radars if it thinks I'm not focusing, (pre cursor to these ADAS things - you can have on or off..), over the years its behavior changes as you flash different iterations of software at modules involved in this stuff from Radars, BAS Plus and Rear SAMs

 

[Ron240]

Ron, on your MBUX car do you think the warning light comes on at a reasonable distance, ass opposed to too early or worryingly late?

It's probably about right I would say. I only ever see it when for instance I change lanes and the car in front is still a bit close, or a car comes into my lane. Whenever the light comes on I agree with it in that the distance is a bit too close for comfort if it was to remain that way.

 

[Botus]

its just the two second rule

 

[Digsy]

It's probably about right I would say. I only ever see it when for instance I change lanes and the car in front is still a bit close, or a car comes into my lane. Whenever the light comes on I agree with it in that the distance is a bit too close for comfort if it was to remain that way.

That's pretty much how I saw it on my B and C. Very different behaviour on my GLB, though. Anyway, I gave my dealership a rundown on what it was doing after two weeks of ownership and it is going to be booked in so they can look at it.

 

[Digsy]

So, MB are finally going to take my car in for a look but I thought this was interesting enough to share:

On top of behaving pretty randomly during normal driving, I have noticed that as soon as the outside temprature gets to zero, all my ADAS functions (speed limit assist, active braking and lane keeping) go offline due to an obscured camera error. This is reasonable enough when the screen is actually frosted up, but check out the two pictures. These were both taken on mornings when it was below freezing, but after fully demisting on my driveway followed by a 30 minute drive. The screen was totally clear apart from a patch of....something...on the screen inside the camera housing. On both days, after the car was left standing (about 9 hours) the camera behaved normally all the way home.

My gut feel is that there is some kind of contamination inside the housing which is screwing with my active braking, and then kills everything to do with ADAS in colder weather.

I don't know much about ADAS cameras but it seems sensible that they should be heated to prevent this. Anyone know if they are?

 

[Botus]

do you ALWAYS have the AC switched on and is it operational ? (note in cold temps it will switch out automatically). if the car interior is not full of water / very high humidity and the AC is left ON to control the humidity - misting issues should be eliminated and the car has a chance to function

my screen has a heater element around the front camera and it doesn't have an issue

 

[Digsy]

AC works and the system is set to auto. Cabin temp is set to 22 degrees both sides. The screen demists fine just not this little bit right in front of the camera.

 

[V6Matty]

There’s the possibility that the screen has been replaced at some point and a tiny bit of moisture has leaked in, may be as simple as taking a hair dryer to it and see it reappears

 

[Digsy]

So MB have had my car in today and unsurprisingly concluded that nothing is wrong with the camera. Interestingly, when I booked the car in and had to re-describe the issue, I mentioned the persistent patch of "something" that remains in front of the camera and got the reply "That's normal but the camera has a built in heater which will get rid of it". So I said that's probably the issue then as it clearly isn't working properly on my car.

When I spoke to the same guy today he seemed to have forgotten all about that and just said they had taken the camera off and cleaned the screen

Oh well. Will see how things go over the next few days when it is cold.