Model X

Sudden and erratic braking on autopilot



  • edited September 2019
    Driving south on I-5 today we had this happen in our MR3 with 2019.32.2.2. So far its not led to anyone slamming into our rear bumper. My Model S does this every so often. Its very random and annoying.
  • edited September 2019
    Many of the same issues on UK roads in MX in NOAP, including phantom braking (especially in low-angled sunlight) plus a few UK-specific quirks.

    1) On joining a Motorway (divided highway) on NOAP, car will request a confirmation of a move to the LEFT "to follow route". Obviously, when joining a UK highway, one moves to the RIGHT. One has to press Tap To Cancel about 10 times before NOAP submits to the human driver's intentions.
    2) NOAP almost never suggests a lane change (to the right) to pass slower moving traffic. I have to initiate this by pressing the stalk myself. If I don't the car will slow to say 60 mph behind slow moving vehicle(s) even though the right (passing) lane is available for overtaking.
    3) Pulling out into the overtaking (passing) lane can be very hesitant and sometimes aborts mid-move with a dangerous swerve.
    4) Pulling back to the left (out of passing lane) is massively over-sensitive to traffic on the rear left quarter, at about the 7 o'clock position. NOAP will indicate the RED lane divider to prevent the car moving back left if there is a vehicle in this position. Even though it could easily move into a vacant slot to the left, it seems to think that the car in the left lane behind will itself accelerate and try to 'undertake' my car. This does not happen in the UK, because passing on the LEFT (the slow side) is illegal.
    5) All the above conditions apply whatever setting NOAP is in, up to and including Mad Max.

    Mine is a 2016 MX, upgraded with the FSD package, with the OLD vision processing GPU hardware. Does anybody have experience of whether NOAP gets any better when the free upgrade to the new vision processing GPU is fitted? Does this even exist?
  • edited September 2019
    This happens when I am using AP around DC (495) when it crosses overpass bridges. It looks like X confuses big shadows (underpass) with real objects.
  • edited October 2019
    I have noticed that my Model S75D will slowdown dramatically from 70->35 MPH when driving BY a freeway offramp when in autopilot in the rightmost lane. Assuming you don't get rear-ended by the car behind you, the car will eventually accelerate back to the normal cruising speed once past the freeway intersection. Still happens on 2019.32.11 tonight on southbound HWY 85 in Sunnyvale. That's about 20 mins from Fremont HQ, so maybe somebody at Tesla can try it :) Thanks!
  • edited October 2019
    This has happened a number of times around the Los Angeles area in my model X 75D. It has happened when cars are slowed down, stopped, or turning in the adjacent lane. Its happened enough that when i get close to slower vehicles i put my foot on the accelerator. It has happened since the update. Not sure if the issue was resolved or I have stopped using auto drive when traffic lanes have different speeds due to congestion.
  • edited October 2019

    So I am looking to purchase my first Tesla X and reading this thread really now gives me pause. The entire premise is getting it to the point of auto driving and if it has issues with brakes out of nowhere from like 65 to 35....hummmm...that's a MAJOR safety issue! Getting rear ended seems likely. Our 2014 Jeep Grand Cherokee does not have such an issue with when using Adaptive Cruise Control, how in the heck can the Tesla, with all of it's super tech, have SO MANY REPORTS of this happening and yet no reply about it? It seems like this goes back months, with several updates rolling out and even ver 10 and it still seems to be a major bug.

    How is this not being addressed or even commented on via Tesla? I mean really, this does not sound like a small issue and one of the "big things" with these cars is the tech and the advanced auto driving it can do. When it brakes for no reason...that is not a good thing by any means.

    Concerned. Yes. Even more so as I was about to put in the order.
  • edited October 2019
    @david - I responded to your similar post in another thread. All I can add is after you’ve driven an MX for about 100 miles or less you’ll NEVER want to see that Jeep again. You just need to believe in the over the air update system that no other auto manufacturer has. It will get fixed and when it does the entire fleet will be updated.
  • edited October 2019
    In the latest builds, final versions of v9 and the first and second release of V10 I've noted a huge improvement in phantom braking. I'd go so far as to say over the last 1000Km of motorway driving I've not had any weird issues, at all.
  • edited October 2019
    I do think this has improved in the last few updates as well, It happened more often previously but has since reduced. I do wish the reaction isn’t as immediate, even if a car was encroaching into the lane there was plenty of time to respond, the AP didn’t have to “take evasive action”. I will say the AP has been steadily getting smoother in its operation of the car.
  • I seem to have greatly improved my problems with sudden slowing down, by changing the "speed limit" setting to "relative" and "+30". You have to be careful how you turn on AP or it will try to go 90mph :) But I've stopped seeing the abrupt slowing down, which I've concluded happens when AP gets confused by an upcoming overpass. It seems to adopt the speed limit of the road crossing over the highway, which may be 45 or even 35mph. The "max speed" suddenly drops to 45 or even 35, and the car slows down... But since I changed my speed limit as described above, I have not seen it happen, at a place it always did it before. This is still a bug that needs a real fix, but at least I seem to have a way to work around it. Now, I've turned AP back to more automatic operation, and am no longer very afraid it will abruptly slow down on me.

    I also notice it now moves over a little, when a big truck is next to me - instead of staying right in the middle of the lane. That is a welcome improvement.
  • edited October 2019
    I've noticed this very regularly since I got the car over a year ago. It seems they haven't been able to even address this issue as of yet.

    I've also noticed that the car will give its loud beep alarm "pre-collision" sound if you are bending on a turn and there is a parked car on the side of that road. The parked car is directly in front of my car, however it will steer out of path when you bend with the road. Very frustrating at is upsets passengers and makes the Model X seem like its unsafe and unable to realize the path of the road.
  • OK sthuhn... I am not familiar (yet) with the parked car problem you describe, but I would be interested to see if you can "fix" your issue with abrupt slowing down, by doing what I did with the +30 relative speed limit setting.
  • edited October 2019
    The sudden braking problem happened to me on the DC beltway. The car braked very hard with a car behind me. Model s100 2018. Software V10 has not fixed the issue. A very dangerous problem.
  • edited October 2019
    I have a new Model X and have had many sudden stops for no apparent reason.
  • edited October 2019
    We drive a lot of country roads ('cause we live in the country :-)), noticed a lot more phantom breaking on V10 so far. Usually by sharp straight shadows across the road. Hopefully this will be addressed in the next few updates.
  • edited October 2019
    I've had my M3 LR for about one month and have experienced this sudden brake issue twice with no car in front. Has anyone had this checked by Tesla to find out the cause and fix?
  • edited November 2019
    Shadows from an overpass across the road seem to be present when my 2017 P100D does the sudden braking. if there is no shadow the MX seems ok.
  • edited November 2019
    I experienced this break for no apparent reason 'feature' twice today. Like inge.lofald said on july 29:

    I would love a menu choice to disable the TACC for an old fashioned regular cruise control, while the braking issue gets fixed.

    Don't know how to tell V9 from V10 (or V8 for that matter) but my software is 2019.27.103, M3LR.
  • edited December 2019
    Randomly see this when on TACC+AutoSteer (EAP Lite).
    I won't engage unless there is nothing else around for a reasonable distance and I'm in the slow lane and I'm feeling up to checking to see if the issue has been addressed yet on whatever firmware version I happen to be on.
    I think I've isolate the issue in my case, it seems to correlate with a off-ramp with a lower speed limit or a service road adjacent to the freeway with a lower speed limit. Speed drops to the off-ramp or service road speed limit and I have to quickly compensate.
    So, to me, it looks like the car gets confused about the location and rapidly decelerates to an alternate path speed limit.
    In all cases I've noted, there are no vehicles within 10-20 car lengths, which is about the best I can do on some of the busy freeways around here.
  • edited December 2019
    @jrahn I agree with your analysis.
  • edited December 2019
    Situation still exists with .40 update. 2017 P100D with all extras except larger wheels.
  • @jrahn, I too agree. But this is getting really old, month after month with no fix. Who is looking at this forum, I wonder? Is Tesla working on this; does Musk know about it? It doesn't seem like it would be so hard to fix. If car is going 70mph, approaching the area of an on ramp, seems it could not possibly be getting ON the highway, so it should be able to distinguish this case from when car is going 20 or 30mph, getting on the ON ramp. This is a really serious issue, and will discourage people from using AP, or from recommending/buying the cars. It needs to be addressed, before adding other less useful features.

    I have noticed at times, that my Model S gets mixed up about where it is, and thinks it's 20 or 30 yards to the right of where it really is. Maybe these 2 issues are related.
  • edited January 27
    No one from Tesla reads these forums. They’re intended for owner conversations.
  • edited January 27
    I am not so sure. Tesla Inc hosts this forum. They must be at least browsing through the postings here and selectively take those postings they think could potentially be a hidden safety issue.

    So I would encourage owners to post their observations here
  • edited April 17
    Model 3 version 2020.8.3
    5 episodes of random emergency braking while on AP.
    ONe going under overpass
    One when divider concrete wall came up on RHS of lane close to car
    One when car next to me swerved toward my lane
    Two others just random.
    my previous car merc c350 E AP function was faultless and much more user friendly.for 3 years

    Tesla you need to sort this big time
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