Automatic: I am happily driving along, following a car in front on a straight clear road with adaptive cruise on when suddenly wham. For a split second the brakes comes on and there is a loud buzzing grinding noise like jumped out of gear. It then carries on as normal, but I am left wondering what the hell just happened! The car is front didn't make any sudden movements or braking and I am in the centre of my lane.
This has only happened a couple of times in the last 10 months so I didn't really worry about it. Put it down to a glitch. However today it has happened twice in quick succession on my way out to lunch I immediately diverted to my Dealer and booked it in for next week.
My concern now is this appears to be a completely random event which the garage will not be able to replicate. I wont pre-judge but I do have a bad feeling about this one. Sudden braking with a car following makes me nervous and they say we can't find a problem. Fingers crossed that they fix it.
Mike wrote: ↑Sat Jul 10, 2021 8:40 am
Sounds like pre collision kicking in and the noise could have been the abs. Ju st a guess
That’s a good shout. I’ll turn off pre-collision active braking just in case. I’ll turn it back on before I drop it off at the garage. It’s difficult to remember all the systems, there are so many …
It could be my imagination, but having turned off the pre-collision active braking (which switches off the evasive steering assist), I am finding the car ‘feels’ much more comfortable to drive. The steering and adaptive cruise just feel better. Perhaps there are less servos in the loop and frees up some system processing! I decided to cancel the dealer visit and added the investigation (which I am now calling phantom pre-collision active braking) to my first convenience check in six weeks time.
When this happened to me there were not any warning lights that appeared on the dash, which I thought when pre collision braking was activated it flashed up a warning??
Ekobuusti wrote: ↑Tue Dec 13, 2022 10:32 am
This happened to me now second time in 6 weeks. Mine is mhev 1.0 A7. I bought it as new and I've had it now for 17 months and driven 12000km.
Does someone know the root cause? I don't want to take it to dealer for "light treatment" in finnish "valohoito"
On both occasions snow was involved and I was on adaptive cruise control behind a car.
This used to happen to me (I was Deleted User 229), It still happens occasionally but my solution was to adjust the pre-collision settings (active braking) in the driver assistance menu to make them less sensitive. For me the at risk time is when driving with winter sun low in the sky with heavy shadows. Only happens (DCT7) on adaptive cruise control. 15 months ago, during the convenience check my dealer said they fixed it but it has happened since (only once, but I have probably jinxed it now).
I immediately diverted to my Dealer and booked it in for next week.
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