Auto Brake and Auto Cruise Problem

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jmatero

Member
Joined
Sep 4, 2015
Messages
14
Hi All
Wondering if any of you have had a similar issue. Several weeks ago, I began to notice erratic behavior with the dynamic cruise and auto braking features. They've worked flawlessly up until now.

Auto-braking: Beeps as you quickly approach something but does not begin braking soon enough (or at all) forcing me to slam on the brakes.

Auto-Cruise: Driving along, the car will suddenly brake as though something is there but there isn't. Or, with it activated and set at 4 bars, it will accelerate towards a stopped vehicle as though it doesn't see it even though the indicator is says it picked it up.

Dropped it off for service this morning and they asked me to drive with a Service Manager. Before he drove us off the lot, I described what was happening and he had a very skeptical look on his face and suggested "don't worry, it will stop" and "the sun glare can cause the cruise to deactivate". I explained it wasn't deactivating, it remains active but stops for no reason or doesn't stop at all. So he accelerated towards several parked cars... the beeping sounded... but he had to hit the brakes every time or we would have driven right into the cars.

The service advisor said he's seen this before and there's a software update that fixes it (?). He also said there's a recall for the motor mount bolt so they're doing that as well.
 
Yes it has happened to me more than once when the cruise suddenly stopped. Glare, shade and trees suppose to do that i heard.

I let the auto braking to do the stopping but its too scary.....too close and then it brakes, so what i do now if it comes to traffic i just lower the set range and then let the auto brake do the rest so i don't have the" feel like the car is not gonna stop" feeling.

Yes the motor mount bolt needs to be replaced.
 
Yes, I've had the cruise control suddenly shut off, or brake, because it thinks it seems something when there is nothing there. It's also very sensitive to car that is just over the lane line. For example the cruise control will stop, rather than drive around, a car that is making a left turn but that has any portion of the car in my lane.

I've also seen it accelerating into a vehicle ahead, though usually a vehicle that is well in the distance. I think this is a case where I know the vehicle is stopped at a traffic light and would not accelerate, but just coast up to the car, but the cruise control is trying to adjust it's following distance based on the cruise control setting so it accelerates, followed by hard braking. I've seen the same thing in my Tesla.

I'm not sure which "auto braking" you are referring to. Do you mean the cruise control stopping the car when in traffic, or the collision avoidance braking?

I just had the motor mount replaced and a s/w upgrade last month so I don't think that's going to help these problems.
 
We just picked up our 2016 with range extender last week, yesterday my wife was driving on an empty expressway with cruise control on and set at 67, there were no other cars on the road, as she approached a "hill" overpass the car braked hard and sounded an alarm. No warning, and in the middle of a three lane 70mph expressway. How scary is that?

I'm guessing this should not be happening, and if there is a software update, surely it must have been done to my 2016. Any suggestions?

Really disturbing my confidence in my ultimate driving experience....
 
The one thing that comes to mind is that once you crested the hill, the sun was full on into the camera, and the system could no longer see properly. When that happens, it does disengage the adaptive cruise control. But, if you have the latest software, you have maybe 2-3 seconds before you get into maximum regen. That differs from the way it was originally, where it would go into max regen immediately...now it ramps up, and if you're paying attention, you can easily get either on the accelerator peal or the brake as needed.

As delivered in the USA, the lane keeping capability has been disabled - probably for liability reasons...we have the highest ratio of lawyers/capita of any country on earth just waiting to sue someone.

When using the CC on any car, you should always be ready to take control. One of the hassles of the automated systems is that people can get lulled into being inattentive, which can be deadly as was recently shown in the fatal accident on a Tesla.

From personal experience, if you're following someone and they start to slow, the car does a great job of keeping spacing and can come to a smooth stop. If you're not following someone and are approaching stopped traffic, it often doesn't start to brake until you're closer than many people would like, but it still does. The logic is looking at the relative size changes as it approaches something, so if it was not already tracking the vehicle, it takes a few cycles to first get a reference, then realize it's closing before it can respond. This is a result, I think, of using only a camera verses say in addition to radar, which could give actual range information. That would be more complex, and use more power, and in most cases, doesn't buy you much for the range you'd give up IMHO.
 
There are two "hill" overpasses on my commute where my i3 has disengaged the adaptive cruise control more than once (at each spot). I travel essentially due south (I-25 north of Denver) in the morning, so the sun is definitely not suddenly on the camera. It occurred as I reached the start of the incline, not at the crest. If I had to hazard a guess, I would say that the system is confused by the road directly ahead. Mine disengages the cruise control giving me plenty of time to press the accelerator without sudden braking.
 
Thanks to both for responding,

The braking & interior alarm happen as she approached the incline, not at the crest of the overpass. She was traveling north, late morning, with the sun at a 3/4 position behind her -- lighting up the overpass. So, very similar to Markn's description.

We do drive sensibly with CC, always have and my wife didn't panic because she was paying attention - we're both still getting used to the car and have driven less than 300 miles on it. Now I may just never use it or the Driver Assist, or the navigation system, I know where I'm going and how to get there -- really I just want to drive the car with confidence.

Maybe the sensors or cameras are miss-aligned? I'll be headed to the dealer tomorrow for a check anyway.

Thanks again.
 
A mass of grey from the pavement ahead without view of the horizon, might also be a trigger for the camera. I have had mine quit as the result of strong, deep shadows on a sunny day. I'd guess that the auto exposure function gets confused by the rapid light intensity changes, and to be safe, rather than just proceeding, it shuts off. The owner's manual lists some things that can affect the system and cause it to shut off.

You CAN turn the adaptive function off, but you have to do it each time you start the car, if that becomes an issue, and then, it reverts to a dumb CC. So, you don't lose that functionality entirely, you can always continue with the dumb CC.
 
I agree with Jim and would only offer this.

The early generations of any new technology will have some 'curious' problems. That it leads us to keeping alert, at least we won't replicate the recent Tesla driver who died when watching 'Harry Potter' and ran into a semi-trailer truck.

Treat it as an 'assist', not something you should bet your life and the life of your passengers on.

Bob Wilson
 
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