Brake assist malfunction

[mcpherlj]

My car is a GLC300 4-matic AMG line, premium petrol engine first registered in 2019.

The problem started with ‘Radar Sensors Dirty’ warning messages. So I would clean the sensors, but the warning messages kept coming.

I then started getting warning messages telling me ‘Active Brake Assist Functions Limited’ and that message now comes on every time I use the vehicle.

I also notice that the Distance Warning indicator is no longer working.

I have have MB look at it. Said the Active Brake Assist system needed recalibrating, but whatever they did failed to solve the problem.

Has anyone had a similar problem and how it was cured? Any advice would be much appreciated.

 

[Botus]

Has it has any gentle car park knocks and prangs? VW's always pop the sensor out of position and switch out assistance if someone so much as looks at the flexy bumpers

then of course calibration is a specialist job and they probably don't even know how to use the equipment - many don't realise main dealers employ sacked McDonald workers and car thieves on probation, whilst paying close to min way. The ones that understood the reset button on a PS5 went elsewhere

we've had a few with water in front sensor wiring loom multiplugs, most cars couldn't cope if you see a puddle at the side of the road, but these days fording a 30 cm flood at 30mph seems to be a daily occurrence - people don't seem to realise smashing a 250mm tyre through a foot of water at 50 mph creates a tsunami that gets water were it wasn't a good idea,

not forgetting the councils make them rust campaign, putting 3mm of salt down everyday from 10 November, doesn't help electrics work right

Go to a proper dealership and try again ?

 

[LostKiwi]

Take it back to MB. They didn't do what you paid them to do.

 

[drsam83]

My car is a GLC300 4-matic AMG line, premium petrol engine first registered in 2019.

The problem started with ‘Radar Sensors Dirty’ warning messages. So I would clean the sensors, but the warning messages kept coming.

I then started getting warning messages telling me ‘Active Brake Assist Functions Limited’ and that message now comes on every time I use the vehicle.

I also notice that the Distance Warning indicator is no longer working.

I have have MB look at it. Said the Active Brake Assist system needed recalibrating, but whatever they did failed to solve the problem.

Has anyone had a similar problem and how it was cured? Any advice would be much appreciated.

How did you clean the sensors ? I only get a warning from the left front side of the car if anything get too close, but If I'm behind any car , radar sensor doesn't respond or beep anymore . I am the 2nd owner of this GLC 300 so I don't know if there were any error messages in the past .

 

[Botus]

two small elements to a dirty sensor - one less obvious one needs a soft toothbrush - a third out of sight nuisance - and the forth obvious likey issue

1) visible road grim, salt, oil, tar, dirt, debris ect over the sensor surface AND the windscreen sensors / cameras if fitted - needs to be removed leaving clean and un-smeard

2) build up of road filth in the tiny gap around the bumper and the actual sensor, this can lead to some issues, a good clean with the toothbrush & soapy water

3) water ingress behind the bumper on a loom connection to the sensor you can't see or check (without pulling stuff apart). Because its all super low volt, low amp canbus madness, a tiny amount of water is enough to make canbus electronics misbehave. The old days of a rusty wire on a mk 2 escort indicator still operating perfectly well when there is almost nothing left of a bare connector thats been through 40 years of salty winters is well passed. One puddle at 25mph or a jet wash is enough to take the whole car down if life wants to give you a bad day

4) of course modern cars all leave the factory with half the software part finished untested lunacy - a number of modules could have software bugs they removed in later updates - this wasn't normal in cars pre-2010 (they were simple enough and the engineers were still ones that had O-level common sense). But now its algorithm junkies adding features no one wants - like connecting the reversing camera to Instagram - because they once wanted the feature to share porn from dogging sites where they used to watch their parents teaching them new world morals

 

[John77]

I had work carried out on my steering and on picking u the car I had the Active Brake Assist Functions Limited. The garage said that it should calibrate itself. I read on here that you can calibrate this by when the car is parked turn the steering all the way to the left, then all the way to the right. This actually reset mine on my EClass and has no happened again since.