Weird feeling/noise slow down at 30 cruise control

[JodyS21]

Anyone else had this?
Twice today, had cruise control on at 30mph, happily going along - no car in front etc.
Suddenly the car starts slowing down with a weird almost grinding noise for a couple of seconds.
A bit like a not in gear properly noise but not quite a bad as that.
A lot louder than the slight noise you get from brakes/regen.
Can't be sure whether noise was coming from wheel or bonnet

Put my foot down and it just accelerated easily, put CC back on ok.

Very odd
1) Why it suddenly cut out of cruise control
2) What the noise was

 

[John G]

Anyone else had this?
Twice today, had cruise control on at 30mph, happily going along - no car in front etc.
Suddenly the car starts slowing down with a weird almost grinding noise for a couple of seconds.
A bit like a not in gear properly noise but not quite a bad as that.
A lot louder than the slight noise you get from brakes/regen.
Can't be sure whether noise was coming from wheel or bonnet

Put my foot down and it just accelerated easily, put CC back on ok.

Very odd
1) Why it suddenly cut out of cruise control
2) What the noise was

Hi, its likely that the collision avoidance system has registered a potential risk. It activates whenever its algorithm calculates a chance of a collision. But it can't see what you can see and its main sensor is down below the number plate so it picks up things that you have already dismissed. Sometimes even a bollard in the road can cause it or a car ahead slowing to turn left - you know it will be out of the way in time but the car only 'sees' that you are steering towards an object that has rapidly slowed down. The noise is the system arming itself to slam on the anchors.

 

[Trevor]

I had this reproducibly on a corner in town, which hasn't happened since comfort update. I wonder whether they've improved the algorithm? The car would slow down, but I don't believe it disengaged cruise control. The noise was unsettling, and difficult to describe.

 

[Cocijo]

The auto braking system is very noisy - almost a grinding sound - but I’m assured perfectly normal.