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Phantom hard braking on autopilot

markr1653

Member
Sep 8, 2015
14
16
Ann Arbor, MI
Hello fellow MX owners -

This issue does not seem to be a new problem with autopilot, but wanted to start a discussion amongst MX owners. I have a 2018 MX with software 2020.36.3.1. I've not had many issues with autopilot until about a month ago, and now with almost every drive with autopilot (daily), I get phantom, unprovoked, hard braking, usually during autolane changes, but also during driving straight.

This is somewhat concerning, as this is a safety issue. If someone is tailgating me, I would most certainly be involved in a rear end collision.

I spoke with Tesla Customer Support, and this has been reported. This was escalated, and I'm awaiting to hear back from the engineers.

Anyone have experience with this?

Thanks.
 
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mswlogo

Well-Known Member
Aug 27, 2018
6,123
4,736
MA, NH
Happens to everyone. Welcome to the club. I’ll go stretches that seems are fine for days and then wham.

One thing you’ll notice is, that it’s not quite as aggressive as it feels. Often it might be like a 10 mph drop. Drop it does it instantly. So it feels worse than it is. I’ve had it happy with people behind me and they didn’t flinch.
 

S4WRXTTCS

Well-Known Member
May 3, 2015
5,631
6,405
Snohomish, WA
This was escalated, and I'm awaiting to hear back from the engineers.
This is why I liked the post.

I think part of why phantom braking is still a thing is customers haven't been loudly complaining about it.

It's so bad that I wouldn't hesitate in giving $1K to charity for the opportunity to dunk tank an autopilot engineer at some amusement park charity fundraiser.
 
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NoSoup4U!

Member
Nov 11, 2018
133
78
Los Angeles
Same year MX, same software version. Started to happen to me again as well. It had become noticably better in 2019 but now I've had it happen 2 times in the last week or so. Not driving every day.
 

dlsspy

Member
Jan 9, 2018
84
96
San Jose, CA
Oh cool, I haven't been driving a lot lately (for some reason…), but have been noticing a lot more of this recently. Thanks for fixing it all for me, everyone. :)
 
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Birdman325

Member
Aug 15, 2017
915
552
Toronto, Canada
Experienced similar on my 3 with the latest software. The past couple of versions I thought were pretty good minimizing (can't say eliminating) phantom braking to a great extent. On Sunday I did a long drive to Montreal and back (about 1,100 km all in) and I have 2 or 3 pretty aggressive instances of phantom braking. As I recall, each time it was while passing a semi)
 

X Fan

Supporting Member
Supporting Member
Sep 29, 2015
2,427
6,129
Naples, FL & Cary, NC
phantom breaking coupled with unexpected moves into non-proper lanes (I was on AP yesterday, exiting off I75 and instead of staying in the two exit lanes it decided to veer into the exit safety area) make this Tesla's worst update in quite some time.
 

Milosmama

Member
Oct 24, 2019
10
0
Fremont
I have this issue with my brand new X. I was going straight and it went from 74 to 40 within seconds. Then it happened again, also going straight. There were no cars in the front, back, nor either side of me, which was good otherwise it would be an accident waiting to happen. I do not have FSD either.

I went to the service center. The technical told me that autopilot is only beta so I should not rely on it. If they can't reproduce it then it will cost be $195. Of course, they could not reproduce it.
 

MEAllard

Member
Feb 3, 2020
70
67
New Hampshire
I accept that we are running Beta, so it is not perfect yet. I have noticed it happens to me most often while passing a truck to my immediate right lane. It is almost predictable for me now, as I pass 1/2 to 3/4's past a truck, and mostly when they move towards my lane, the phantom brake hits. I am ready for it now, have caught (anticipated) it twice.
 

DoctorVenkman

Member
Jul 29, 2018
428
520
Los Angeles
This last update seems to have brought it back for me in a really bad way. I went for 6-12 months without any phantom braking incidents, but since this last update they have happened consistently every 15-30 minutes. It's gotten so bad I refuse to use AP until the next software update.
 

Stach

Member
Mar 23, 2019
464
246
Madison, WI
You can view my major phantom braking incident (from 65-40mph) last night in the link below, at the 47 second mark. There was absolutely no reason for it and it scared the crap out my girls in the back seat (and me too). I have no doubts that it would have completely stopped me, right in the middle of the freeway, if I hadn't pressed the accelerator. I was only using TACC, and I'm not sure if TACC is in beta as well? I will say that the video doesn't do it justice, as it felt much worse than the video shows (probably because the front end doesn't dip very much with the good suspension).

4 Google Drive Dashcam Videos

Also, here's what the TeslaMate data shows from that time.

upload_2020-9-16_17-51-44.png
 
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markr1653

Member
Sep 8, 2015
14
16
Ann Arbor, MI
Thanks for all the replies. I've done some searching, and this issue of phantom braking has been well documented for over a year now, with many posts on the forums and YouTube.

The weird thing is, is that for about 28,000 miles on my 2018 MX it maybe did it once or twice (overpass), but since the recent software updates (2020.36.3.1) it does it almost every use of autopilot on the highway. It's bad. It's scary. Again, if someone is tailgating me, I'm going to get rear-ended. It happens while passing semis, or while driving just straight, or making lane changes. I tried turning off Emergency Braking, and it still is happening.

I'm supposed to be hearing back from the engineers as the Tesla customer service person I spoke to said she would escalate this to the engineers. I'll post what they say when I hear back. I'm sure Tesla's response to any autopilot issue is that it's still "beta".
 

DoctorVenkman

Member
Jul 29, 2018
428
520
Los Angeles
Thanks for all the replies. I've done some searching, and this issue of phantom braking has been well documented for over a year now, with many posts on the forums and YouTube.

The weird thing is, is that for about 28,000 miles on my 2018 MX it maybe did it once or twice (overpass), but since the recent software updates (2020.36.3.1) it does it almost every use of autopilot on the highway. It's bad. It's scary. Again, if someone is tailgating me, I'm going to get rear-ended. It happens while passing semis, or while driving just straight, or making lane changes. I tried turning off Emergency Braking, and it still is happening.

I'm supposed to be hearing back from the engineers as the Tesla customer service person I spoke to said she would escalate this to the engineers. I'll post what they say when I hear back. I'm sure Tesla's response to any autopilot issue is that it's still "beta".

It varies with each software update. Most of the time it's fine, and then you will get one bad software version and AP is unusable.

The AP software, and neural nets in general, are so complicated that fiddling with something can have unintended consequences. I wish there was a way to revert the software version in cases like this when AP is clearly flawed in a dangerous way.
 

Shateam

Member
Apr 13, 2016
590
547
NJ
You can view my major phantom braking incident (from 65-40mph) last night in the link below, at the 47 second mark. There was absolutely no reason for it and it scared the crap out my girls in the back seat (and me too). I have no doubts that it would have completely stopped me, right in the middle of the freeway, if I hadn't pressed the accelerator. I was only using TACC, and I'm not sure if TACC is in beta as well? I will say that the video doesn't do it justice, as it felt much worse than the video shows (probably because the front end doesn't dip very much with the good suspension).

4 Google Drive Dashcam Videos

Also, here's what the TeslaMate data shows from that time.

View attachment 588946

I wonder if the phantom braking was caused by the speed limit sign which is also at the 47 second mark.
 

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