GLC2020

I had a terrifying experience in my brand new GLC on my commute home. Driving along in heavy traffic, car abruptly makes warning sound and immediately brakes on its own with no apparent hazard in front. There were ~ 5 car lengths in front of me. I thought there was supposed to first be a visual warning, then the sound, and only then the auto braking. It terrified me because if someone had been following at all close as is usual in the traffic I drive in they may have rear-ended me. Thoughts? Anyone else who drives in city traffic experience this? It was freezing cold but not raining or snowing if weather could be a factor. Do I need a warranty service visit?

aweber1nj

That does sound pretty scary. IIRC, there are settings for how aggressive you want your Active Brake Assist to be. Even on the "highest" setting, I think your experience sounds wrong.

Please let us know what you find out? I just got my 2020 and would like to know!

Good Luck.

superswiss

The system can initiate autonomous braking directly if it detects an immediate critical situation. In that case you get the warnings and autonomous braking simultaneously. The system not only reacts to cars, but also cyclists and pedestrians. If none was in your vicinity then it sounds like a false positive, which can occur. These systems are not 100% perfect. You can override it with the throttle. Should read the Active Braking Assist chapter in your user manual. Do you have the driver assistance package? It works different and is more sophisticated with the driver assistance package. Main differences with the driver assistance package is that it also reacts to crossing cars and stationary cyclist and pedestrians. You can change the sensitivity in the vehicle settings or turn it off. Options are Early, Medium and Late. I believe Medium is the default.

6G Schnell

It is not just about the distance. Car is taking the speed and the rate of change into calculation and decides when to brake. We all understand that braking distance at 65 mph is much more than at say 30 mph, correct?

My real life example: driving at HWY speed, cars in front started braking unexpectedly. I was looking somewhere else for a split second and did not even slow down. Then there was a beep, seat belt tightened, side bolsters extended out keeping me in my seat, car started braking! The good news is car stopped at the safe distance.

Took a deep breadth and said Thank You to MB engineers that designed the system!

achez

I have this issue every day. When driving slow, about 20mph or less and go under an overpass, the car abruptly makes the warning sound and slams on the brakes. It then immediately picks up speed again. Usually does it when the car in front of me is accelerating but never does it when if the car in front of me is stopping. I've had it back to the dealer and they 'cannot recreate the issue'. However, I have this happen at least once per day often times more. I've tried turning off active braking but the car still does it. I have the driver assistance package. I no longer use it in slow stop and go traffic. It's too intrusive to tolerate. I am not very happy about this since the main reason I got the driver assistance package was for stop and go traffic on the highway.

lay3r3

A birthday mylar balloon once was floating along the road I was traveling of 45 mph speed limit. Unluckily it "floated" right in front of my Audi Q7... brakes locked up,seatbeat retracted hard, phone fell out of wife's hand with her screaming at me "wtf are you doing!"

Good times.

aweber1nj

ROFL

decorily

Nothing new so!

achez

so, in other words the “air bag” went off as well!!

decorily

Reminds me of a comedy show where a guy was missing his beloved, who was away, so he went for a drive and set the Sat Nav and kept taking wrong turns on purpose so that the female would keep telling him where to turn and how to get where he wanted to go!!!