[Speedbird1]

Not sure if I read on here that someone had experienced the same issue, (I have searched) but wondered if this has happened to anyone else recently:

Having entered a slip road (on-ramp) to a local motorway at approximately 50mph, I was just starting to accelerate up to m-way speed (70mph) when my car performed an emergency brake. A sound like a bell went off, a red symbol flashed in the HUD and the car slowed dramatically to about 30mph. Luckily there was no one behind me to get caught out. There were no cars in front of me for about 1/2 mile. The nearest car to me had been beside me, in a different lane and a little behind, about 10 seconds before.

Car not overly dirty, checked sensors in windscreen and no obvious reason for wrong detection. Car had just clicked over 1000 miles. There was no advance warning, the car just went into acute warning with brake function.

Obviously I will monitor and dive into dealer if it occurs again but it was a bit startling to say the least.

[redkite]

RTO

[OzX3M40i]

ECAM actions

[MechX3M40i]

It does seem like Forward Collision Warning was activated. Was the 'on ramp' curved? Windscreen clean where the camera is?

[AnOldBiker]

Its situations like this that bothers me. Too much manufacture control for so call safety. I'd document this at the dealership and let them check this. Then if this gets you in trouble in the future, like someone rear ends you when this happens.

I also don't like the cruise control. If you're going down hill to fast, the rpms ramp up and its an aggressive slowing in speed, where to prior vehicles I've had just dropped rpms to slow me down.

[MechX3M40i]

Originally Posted by AnOldBiker

Its situations like this that bothers me. Too much manufacture control for so call safety. I'd document this at the dealership and let them check this. Then if this gets you in trouble in the future, like someone rear ends you when this happens.

I also don't like the cruise control. If you're going down hill to fast, the rpms ramp up and its an aggressive slowing in speed, where to prior vehicles I've had just dropped rpms to slow me down.

Regarding the rpm... Wasn't the car doing what it's supposed to when going downhill? By shifting down a gear or two to engage engine braking, and therefore, rpm went up during that moment?

[AnOldBiker]

On me other vehicle, the rpms drop and the speed drops. Same with the prior vehicles I've owned.

[nogren]

Originally Posted by AnOldBiker

On me other vehicle, the rpms drop and the speed drops. Same with the prior vehicles I've owned.

You mean using the disc brakes?
If so, I prefer the current solution.

[AnOldBiker]

No, no brakes applied until I needed to stop

[HighlandPete]

Originally Posted by AnOldBiker

No, no brakes applied until I needed to stop

Are you referring to Dynamic Cruise Control, or Active Cruise Control, when you mention higher revs, (down shifting)?

BMW's DCC and ACC, both use braking as part of the function for controlling speed.

[Speedbird1]

[QUOTE=AnOldBiker;24356103]Its situations like this that bothers me. Too much manufacture control for so call safety. I'd document this at the dealership and let them check this. Then if this gets you in trouble in the future, like someone rear ends you when this happens.


Good idea AnOldBiker - think I'll do that. If a car had been close behind me they would certainly have been surprised and probably wondered what the hell I was playing at considering the road ahead was clear. Car was relatively clean and sensors all free of winter crud so not sure what could/would have triggered this.

[nogren]

Originally Posted by AnOldBiker

No, no brakes applied until I needed to stop

I don't understand. If the car slows down, either it has to use the engine break (usually higher revs), or disc brakes.
But perhaps you think BMW trying too hard to save some fuel; and letting the speed vary a bit too much? I noticed it let it vary quite a lot in Eco Pro. It's even documented in the manual; and the marker in the speedo increase and cover a quite large range.

[IM_ALL_IN]

You can read about my experience here : https://x3.xbimmers.com/forums/showthread.php?t=1565206

I had a car adjacent to me when it happened. Have since changed intervention or whatever it is called from early to late...no problems since.

[SROC3]

Mine just doesn't work at all. So I guess I don't experience these issues.....(sigh). Dammed if you do and dammed if you don't I guess. After reading these posts of random errors....I'm kinda glad I didn't get the Driving Assist +. I just came from a 120 mile drive, 60 miles each way on freeways. Cruise control worked wonderfully. The car is so smooth and balanced I actually took my hands off the wheel many times and it just cruised straight, even over uneven undulations. Maintained composure very well. It was almost like having Active drive Assist

[Tchgrif]

BMW engines rev too freely, to reduce speeds going downhill in cruise it need to down shift. most cars just need to let the engine slow down to drag the car down.

[Speedbird1]

Originally Posted by IM_ALL_IN

You can read about my experience here : https://x3.xbimmers.com/forums/showthread.php?t=1565206

I had a car adjacent to me when it happened. Have since changed intervention or whatever it is called from early to late...no problems since.

Many thanks, I thought I'd read something about sketchy DA on here somewhere just couldn't find it. So I have DA (not DA+) and yesterday it activated again, this time though just the red blinking car in the HUD and no brake activation. Circs were normal traffic coming towards me on 2-lane highway and nothing in front. I had just passed a cyclist but the red light came on after I passed him so still a bit wary now. I think a trip to dealer to lodge the issue will be my first action and meanwhile I will change intervention to LATE and continue to monitor any more strange activations.

[XXX3]

Originally Posted by Speedbird1

Many thanks, I thought I'd read something about sketchy DA on here somewhere just couldn't find it. So I have DA (not DA+) and yesterday it activated again, this time though just the red blinking car in the HUD and no brake activation. Circs were normal traffic coming towards me on 2-lane highway and nothing in front. I had just passed a cyclist but the red light came on after I passed him so still a bit wary now. I think a trip to dealer to lodge the issue will be my first action and meanwhile I will change intervention to LATE and continue to monitor any more strange activations.

I don’t have DA or DA+, but is there a way that you can disable both DA and DA+? Hope you get this issue sorted out before it causes an accident.

[Cee400]

So the frontal collision will activate for no rhyme or reason. The other day I was on a slight incline road and it decided to apply the brakes with a loud bell noise.
I have tried to be close to cars ahead of me to see if it will activate and it hasnt, something tells me that its a sensor issue. Have changed the settings from early, medium to late and no changes observed.
My concern is that as with all problems car related this cannot be replicated at will and the dealer will come back and say its all good.

[nogren]

Originally Posted by Cee400

So the frontal collision will activate for no rhyme or reason. The other day I was on a slight incline road and it decided to apply the brakes with a loud bell noise.
I have tried to be close to cars ahead of me to see if it will activate and it hasnt, something tells me that its a sensor issue. Have changed the settings from early, medium to late and no changes observed.
My concern is that as with all problems car related this cannot be replicated at will and the dealer will come back and say its all good.

Bring it up anyway. If lucky they can read out a fault code.
It's definitely a sensor (camera) issue.
They have programmed it to be very late intervention, so it's hard to test. And we should never feel like we are nannied while driving.

[Speedbird1]

So it's been just over a week or so since I posted, and another 400 miles covered. Intelligent assist currently set to LATE, sensor areas spotlessly clean and so far no more unpredictable interventions. I have logged the issue with my dealer, and they have agreed for me to continue monitoring and bring the car in if it occurs again. They will then run some diagnostics / check for fault codes. They said they weren't aware of any other customers with this issue and could not offer an explanation. They said the sensors are designed to work even when dirty and should not be affected by usual road grime. So over next few days, I will cycle through the settings back to MEDIUM and EARLY and continue to monitor. I will update the thread with any action I have to take should it occur again. I'm grateful for all other advice and shared experiences here.

[CAMOETO]

I'm afraid on this system even though it hasn't malfunctioned in my F22 yet. Won't be ordering the DAP on the G01 because the warnings are super annoying when it thinks you're following too closely, even though I have never had emergency braking come on yet. Unfortunately it's bound to become standard at some point in time.

[Fenders]

I just had this happen to me yesterday evening. I've had the alarm and the red car icon in the cluster on a few occasions, but never the forceful auto-brake. I was on the Mass Pike in thick 25mph traffic, and decided to move into the left lane when an A7 in front of me slowed. The Pike has pretty tall cement barriers on the left shoulder, and right at the point where I decided to change lanes, the barrier segment was angled - and set off full City Collision Mitigation. I must have gone from 25 to 5mph in about a second and had to immediately override and accelerate to avoid being rear-ended.

I've always had it set to Early - and I plan on leaving it there, but will be more mindful if I try that maneuver in the future.