Brakes applied themselves at approx 8 mph

[Delboy0127]

Hi No I am not going mad I have had 35 years in the Motor trade and have never come across or heard of this before.

S213 220d Premium AMG Line 2017 Reg 40000 miles from new. Maintained by Main Mercedes dealership from new I am the only owner.

Today I had pulled up at some traffic lights, a Longwheel base Landrover came out in front He was stuck out in the middle of the road, the lights changed for me to go, so I had to wait until he moved forward As he moved forward so did I , I was never any closer that 3 metres from him. As I pulled away my very maximum speed was 5 to 8 miles per hour. The Brakes applied by themselves and literally stopped the car dead on the spot no skid at all, in the middle of the road, the vibration from the ABS applying could be felt though the whole car. My friend and colleague was sitting beside me and wondered what the hell at happened a single decker Bus almost ploughed into the back of me he stopped about 1 foot from the back of my car. After the incident the brakes were free and not stuck on, the engine did not cut out at all . I reported the incident to Mercedes who also had never heard of it before. I can sure everyone I am not going mad, this is a 100% genuine incident.

Your sensible comments are most welcome.

 

[renault12ts]

88mph or 8mph???

 

[Delboy0127]

88mph or 8mph???

Sorry Yes obviously 8 mph How do I edit the title please

 

[st13phil]

Was there an accompanying beep? It sounds very much like Active Collision Prevention Assist engaged - for whatever reason.

 

[Delboy0127]

Was there an accompanying beep? It sounds very much like Active Collision Prevention Assist engaged - for whatever reason.

Thank you Phil Would plug in to Star assist do you think , Ps any ideas how I amend thread title I have put 88mph instead off 8 mph

 

[st13phil]

Ps any ideas how I amend thread title I have put 88mph instead off 8 mph

Report the thread and ask a Mod to change the title.

Would plug in to Star assist do you think

I would have expected a sensor fault to show up on the dash, so I doubt it's a "fault" as such; rather the car's radar sensor(s) determined that the car was accelerating into a closing gap towards a vehicle that was in front but moving more slowly and engaged Collision Prevention.

FWIW, I've had my W177 A-Class do that on the odd occasion, although not so violently. The most common case is when I've been closing on a car turning left out of my path and I've proceeded happy that it would clear before I got too close to it, yet the system beeps and applies the brakes. In short, the system is generally very good but can sometimes get "confused".

 

[Delboy0127]

Report the thread and ask a Mod to change the title.

I would have expected a sensor fault to show up on the dash, so I doubt it's a "fault" as such; rather the car's radar sensor(s) determined that the car was accelerating into a closing gap towards a vehicle that was in front but moving more slowly and engaged Collision Prevention.

FWIW, I've had my W177 A-Class do that on the odd occasion, although not so violently. The most common case is when I've been closing on a car turning left out of my path and I've proceeded happy that it would clear before I got too close to it, yet the system beeps and applies the brakes. In short, the system is generally very good but can sometimes get "confused".

Thank you Phil you have been very helpful and knowledgable really appreciate your help

 

[Ted]

I have experienced exactly the same as @st13phil in my Jeep - car in front turning left - fully aware of it but the collision prevention activating. I set it to be less sensitive when I was able to.
It has also come up with the ‘brake!’ Warning a couple of times when not expected -e.g. coming up behind a cyclist who is in a marked cycle lane.
As the others, my guess is collision prevention activated when you weren’t expecting it

 

[Delboy0127]

I have experienced exactly the same as @st13phil in my Jeep - car in front turning left - fully aware of it but the collision prevention activating. I set it to be less sensitive when I was able to.
It has also come up with the ‘brake!’ Warning a couple of times when not expected -e.g. coming up behind a cyclist who is in a marked cycle lane.
As the others, my guess is collision prevention activated when you weren’t expecting it

Thank you Ted for your reply `I t appears it is the collision prevention activating totally unexpected. Car goes into Mercedes for Service and Mot next Wednesday will ask them to check it out.

 

[KillerHERTZ]

Sorry Yes obviously 8 mph How do I edit the title please

Fixed

 

[Doodle]

There's a function on the Cupra called manoeuvre braking - basically it activates the brakes if you're doing low speed (i.e. parking) and the sensors spot something. It's generally abrupt and unexpected - random bits of grass on our driveway will set it off for example.

Wouldn't be surprised to find a similar system on the 213.

 

[Delboy0127]

I have experienced exactly the same as @st13phil in my Jeep - car in front turning left - fully aware of it but the collision prevention activating. I set it to be less sensitive when I was able to.
It has also come up with the ‘brake!’ Warning a couple of times when not expected -e.g. coming up behind a cyclist who is in a marked cycle lane.
As the others, my guess is collision prevention activated when you weren’t expecting it

Thank you Ted for your reply `I t appears it is the collision prevention activating totally unexpected. Car goes into Mercedes for Service and Mot next Wednesday will ask them to check it out.

There's a function on the Cupra called manoeuvre braking - basically it activates the brakes if you're doing low speed (i.e. parking) and the sensors spot something. It's generally abrupt and unexpected - random bits of grass on our driveway will set it off for example.

Wouldn't be surprised to find a similar system on the 213.

 

[Delboy0127]

Thank you doodle it seems quite common frightens the life out of you when it happens

 

[Delboy0127]

Fixed

Thank you

 

[MrGreedy]

A colleague had this on a new Audi A6 about 3 years ago. However, theirs did it from about 60mph. Twice.
Thankfully roads almost empty both times. Audi couldn't find anything wrong. So colleague stumped up the cost to end the lease early and got the hell out, as they couldn't trust the car (understandably).

My point being, it might be possible that Merc can't find a 'fault' and the system was being over cautious as designed (if possibly risking rear shunting accidents in the process).

 

[Delboy0127]

A colleague had this on a new Audi A6 about 3 years ago. However, theirs did it from about 60mph. Twice.
Thankfully roads almost empty both times. Audi couldn't find anything wrong. So colleague stumped up the cost to end the lease early and got the hell out, as they couldn't trust the car (understandably).

My point being, it might be possible that Merc can't find a 'fault' and the system was being over cautious as designed (if possibly risking rear shunting accidents in the process).

Thank you

 

[SeagullFan]

had the same on BMW530 and X6. All at various speeds. Bloody scary when it happens

 

[Bobby Dazzler]

I doubt Mercedes will find a fault. Like Phill, I suspect that the car sensed a collision with the Land Rover and braked for you.

 

[m80]

I've no experience but would collision assist have some dash indication?

 

[st13phil]

I've no experience but would collision assist have some dash indication?

It does (a flashing red triangle), together with an audio "beep", but the first time it happens the last place you'll be looking is the instrument cluster! That's why I asked about the "beep" in post #4 as the OP may have noticed that but would be highly unlikely to have seen the red triangle warning.