Help with dangerous brake assist fault

[SammyTee]

Hi I've got a 2001 Mercedes 230k Kompressor Cabriolet which I bought for the wife. She's been well looked after and I take her to a merc specialist. Last month my wife was going down the motorway. Suddenly the Bas Esp light came on and the car started braking on its own accord. Luckily she was just joining the slip road so managed to pull off. She rang me and I came. I drove the car home but twice on the journey again the car started braking off its own accord. The yellow exclamation mark on the dials also flashed intermittently when the car started jolting to a stop.
Did some homework on google and found it could be a faulty brake switch. Replaced this and everything was fine for 2 weeks. Now the problem has returned. And it nearly caused a big pileup on a dual carriageway.
How is it normal to have drive a car that has a life of its own? It's like living with 'Christine' I'm a driving instructor so am used to sudden braking etc BUT I decide when it happens.
Can anyone suggest a course of action? Surely to god Mercedes Benz must know about this dangerous fault? Any help appreciated.

 

[BlackC55]

I suspect a wheel speed sensor issue. The Car maybe "thinking" that a wheel speed is massively higher or lower than the others. Is the steering wheel straight? I've seen poor wheel alignments (when the steering is so far out) that the ESP "thinks" that you are turning at high speed even if you are going straight.

You need to get it plugged in to a Star firstly to check for codes. Then up the road with a Star connected to see what the actual wheel speeds are.

Do you have the correct size wheels and tyres?

 

[SammyTee]

The car came with Mercedes Alloys 19 inch 235, 35, ZR19 wheels.

 

[SammyTee]

Thinking about the times it's happened ive never had to turn the wheel a great deal. Would mercedes laugh at me if I tell them the issue? After all it's horrendously dangerous . I don't even want to drive the car on a motorway if I'm thinking 'what if'

 

[1001ab]

You need to get it plugged in to a Star firstly to check for codes. Then up the road with a Star connected to see what the actual wheel speeds are.

I can't see you getting any better advice than this. The description you gave screams "sensor fault" to me so it should be logging codes.

The dealer could help but an Indie specialist might be more economical and, in my experience, more helpful in fixing an intermittent problem like this.

Sorry, I've said intermittent but I'm not sure that's what you're saying. Does it happen all the time, like first time every time, or does it need to be driven for a bit to see the fault appear?

 

[hondo]

W202s ,both front on my w208 and all that happened each time was warning light came on and no abs or traction control ,I defo would not be driving car till you get to the bottom if this

 

[hondo]

Don't know what happened there should read Iv had to replace three speed sensors on w202 and both front on w208 and all that happened with them when speed sensor was faulty was warning light came on (abs /bas) and abs traction control didn't work .