Sudden and erratic braking on autopilot

Sudden and erratic braking on autopilot

I have recently encountered a few incidents where my model x suddenly brakes while on auto pilot on the highway with no reason that I can think of.

It mostly happens when a car ahead changes lanes and moves out from the front. My normal distance setting between cars is 5 but I have noticed this at 4 and 3 too. My car brakes even though there is traffic ahead that is continuing to move normally. So for apparently no reason that I can fathom.

I had another scary incident today when my car braked with no change in front. It appeared to me that the autopilot had a false positive and felt someone was changing lanes and coming in front of me. But that wasn’t the case. I was lucky that I was able to disengage auto pilot and get back on speed or I would have been rear ended.

It’s happened erratically and is scary as it occurs on the highway at cruising speed and can lead to a bad accident / getting rear ended.

Has anyone else encountered this.

RT_TMX | 27 februari 2019

Is there a fix or setting that anyone is aware of that will fix this. I am on the latest version of the software.

lilbean | 27 februari 2019

Fix: don't use it.

lilbean | 27 februari 2019

Patient: Doctor, it hurts when I do this.
Doctor: Don't do that.

d.cherin | 27 februari 2019

I have noticed two new issues with the 2018.50.6 update. 1) Hard braking in AP when passing other vehicles. (AP thinks the vehicles are encroaching on your lane, they are not). 2) when breaking out of AP by turning the steering wheel, the set TACC speed defaults to the actual seed you're traveling, very annoying.

mbp11 | 27 februari 2019

I have noticed this too. The Tesla does not like adjacent trucks or cars.

PXChanel | 27 februari 2019

Autopilot is not ready for use on the streets, still beta. Tesla offered me a 2 week free trial and did not like it, it did what you describe and more. I even tried to get out of the trial and could not, had to live out the full 2 weeks of trial. If you feel it is dangerous, don’t use it. I have owned 2 Model XS and did not get Autopilot on either one bc I felt AP is not ready for mass use, based on the research I have read, experts agree, and I am super happy with my Tesla vehicles. Best cars I have ever owned.

Vawlkus | 28 februari 2019

Works just fine for me. Does wonders to reduce my stress levels on my work commute.

MX2.O | 28 februari 2019

It has happened to me one time in the last 10 days. It happened while I was driving on the highway. There was no overpass bridge or anything like that around when it happened.

bryanle1 | 28 februari 2019

This happened to me too, twice in same day. First one I was in a fastrak lane, no cars around, freaked me out. Second time I was on a 5 lane highway, no cars near me. I'm on 2018.50.6

mbp11 | 3 maart 2019

So, should we press the voice button on the steering wheel and report “bug report- inappropriate breaking on autopilot” so Tesla can pull the logs and see what happened to improve the software?

Mike P | 4 maart 2019

I have AP 1 that experiences some unnecessary braking in non-interstate traffic when the car ahead moves to to an adjacent lane to make a right or left turn. I know that TACC is not recommended for use on other than limited access highways but I like to use it on local roads so I keep my foot on the accelerator and anticipate the anomalous braking and smooth out the transition by pressing the accelerator. I have not experienced this braking on Interstate highways.

inge.lofald | 10 maart 2019

I have a feeling that this issue, althought it has been present all the time, has become worse after the last update (2019.4.3 on my MX). This happens a lot both on limited access multinlane roads and on regular two-lane highways, in the latter case mostly with oncoming trucks, even though I keep well on my side of the yellow line. Extremely annoying, I am about to get a heart attack every time.
I was in Germany a couple of weeks ago, and drove a VW Touareg rental. The TACC on that car worked so much more smoothly than my Tesla. Sorry to say so, but most cars at half the price (or less) has much better TACC. If Tesla cannot fix this issue, I hope they at least can give us a setting to switch between TACC and regular dumb cruise control. That´s better than having to keep the foot on the accelerator all the time.

William9 | 10 maart 2019

False positive braking while on AP is just Elon's new approach to keeping drivers "involved!"

jjgunn | 11 maart 2019

Remember, it's not Full-Self's driver assist

Stay alert at all times!!

gchaurais | 13 maart 2019

[2019.4.3, MX] I completely agree with inge.lofald. Before the update, it'd happen every once in a while. After the update it's 5-10 times a day. It's absurdly inconvenient and dangerous (mainly for the car behind, of course). Does anyone know if there's a way to recalibrate auto pilot? Perhaps that'd fix the problem for me?

Steve | 25 maart 2019

I have found AP sudden braking to be a fairly common occurrence (2019.5.15). Generally happens when I pass a large truck. Once while passing under a bridge with no other cars around and several seemingly random times.

mathwhiz | 25 maart 2019

OP (@rajattaneja) ... Pls specifically identify the firmware version, esp when discussing Autopilot.

jas.107 | 29 maart 2019

Just got 2019.8.3 and started getting more false alarms on TACC.

jas.107 | 29 maart 2019

Forgot to add this information. LR M3 RWD

rrmacha | 29 maart 2019

Yes I have. It started happening after the 2 software updates ago.

jjgunn | 30 maart 2019

Hopefully 2019.8.4 resolves it.

Be sure to reboot after it gets installed successfully.

Micpad | 30 maart 2019

Found the same but the neighboring car is riding the line with my lane.

jacques | 31 maart 2019

Been using autopilot for years and never had issues and for the last 2 weeks in getting random hard braking at high soeed (about 5 times in lag week) in highways... I'm starting to get scared engaging ap. It generally feels much more "nervous" since 2018.9.3

christopher.j.schein | 25 april 2019

After the guy got killed in Cali on AP these false positives have increased drastically. And I hate it. What i do is submit a bug report every time this happens. Just push the speech button on the steering wheel and say "Bug report false positive breaking event at freeway speeds". If every one does this the proper attention will be given to this problem. there was an area of I-5 that always did this and after 15-20 reports they fixed this.

David Trushin | 25 april 2019

I found on a recent trip that overpasses sometimes caused this to happen. I suspect the software is being overcautious about detecting cross traffic. I still don't care for the automatic lane centering strategy. It takes you off the road and onto exit and entrance lanes. Once it took me to the middle on a 1 to 2 lane expansion and I didn't wait to find out which lane it would decide to use. The car behind me assumed I was headed for the right lane and started to pass. It shouldn't deviate from the stable lane marker more than a few feet imho. Still beta.

sgehlhoff | 28 april 2019

I think I’ve nailed it down as to what causes it. When there’s a car in a front quarter position, say at 1 o’clock, and the road turns opposite direction, in this case to the left, Tesla thinks its a cut in and brakes aggressively to allow car in even though its not changing lanes.

sgehlhoff | 28 april 2019

I think I’ve nailed it down as to what causes it. When there’s a car in a front quarter position, say at 1 o’clock, and the road turns opposite direction, in this case to the left, Tesla thinks its a cut in and brakes aggressively to allow car in even though its not changing lanes.

bhoppy54 | 30 april 2019

It's happened quite a few times to me, being I travel around Philadelphia quite a bit. It seems to mis-read cars around me and certainly is freaky, but I've learned that I won't/ can't trust this ModelX 100% of the time

bp | 1 mei 2019

During a 30 minute drive last night - had 4-5 times under NOAP with rapid braking while driving at highway speeds in heavy traffic.

This appears to be caused by the new "Fleet Speed" feature added recently to NOAP/TACC that automatically reduces vehicle speed based on the speeds Tesla has recorded for other vehicles on the same section of road.

This happens without any audible or visual warning, other than the speed decreasing on the speedometer and sometimes (but not always) reducing the TACC speed.

Especially in areas of recent construction, relying on "Fleet Speed" is as bad a strategy as relying on the poor data in the onboard speed limit database.

Plus it has the same flaws that Musk pointed out with the use of HD maps for AutoPilot - relying on past driving history doesn't necessarily reflect current driving conditions - and the correct strategy is to have the AP system do what a human driver would do - and use the current road conditions and signs to control operation of the vehicle.

Tesla should either quickly fix the unnecessary braking (which is a safety hazard in heavy high speed traffic) OR, at least in the short term, add a setting to disable automatic speed adjustment.

Vawlkus | 1 mei 2019

Can’t fix what’s working.

vkonopko | 9 juni 2019

Happened to me 2 times today with 30 seconds interval. Was going under bridges during the day light. | 11 juni 2019

I've had the car brake for no clear reason any number of times, but lately it is much more severe. The other day it not only wanted to slow the car abruptly, it wouldn't give up. I kept pushing the accelerator to maintain speed, but for maybe half a mile every time I took my foot off the pedal it would slow down again. The cruise settings did not change in this case.

In other cases I am on a highway and the set cruise speed would change from 60 to 35 MPH, then a tenth of a mile or so restore to the original setting!

Teslas are possessed by the devil!

David Trushin | 12 juni 2019

Overpasses are often interpreted as obstacles by the cruise control.

jae.y.chung2 | 17 juni 2019

+1 for reporting this. Is there a way on how to report back these incidents so we can give more data points to Tesla to improve AP stability?

Was on multilane high on auto-steer. Nothing in-front or surrounding but there were cars coming from the back. It very suddenly slowed down, almost like breaking. I had to push on accelerate to keep the car moving forward. Thankfully the car in the back was paying attention and he/she changed lane as well.

Version 2019.15.103 a86d242

CEPLENSKI | 18 juni 2019

This happens/has happened for the past year, and is worse lately. We are on 2019.20.2 and get random ghost brakes at 60+ MPH when there aren't even any cars around. Just slams on the brakes and stays at 20mph until I disengage. Also veers towards dividers between highways with regularity.

tesla | 20 juni 2019

Having the same problem. It's gotten so bad I'm afraid to use AP. Been submitting bug reports every time it happens.

On 2019.16.2 73d3f3c

beaver | 20 juni 2019

The Model X I am driving did the phantom emergency slam on the brakes today driving 70 mph. There was a bridge overpass in front . I drove 1,500 miles with no issues. Then it happened today after I updated to 20.1.2

jjgunn | 21 juni 2019

Same on the P3D.

Bridge overpass seems to be the culprit.
Also, was on the far left lane & had a van to my right. Braking for no reason. Car in front of me was about 15-20 car lengths ahead.

Tesla really needs to resolve this issue

bhoppy54 | 21 juni 2019

I've had similar situations! It happened when I was on the PA turnpike in the pouring rain so I thought that may have made the car react erratically. But I've experienced it a few other times too

teslarama | 21 juni 2019

I'm experiencing this on the same spot (bay area, I-680 South bound..near mission blvd exit) every day.
I'm on 2019.20.1.
My colleague has 2019.15 on M3..and it does not have this problem.
Stupid thing. Just slows down for no reason.
I'm on the left most express lane and nothing in front of my car.

jjgunn | 21 juni 2019

@teslarama - anything overhead when the braking happens on 680 (like FasTrack)??

Had it happen on 880S, couple miles north of 238 today & 80W around Ashby Ave in Berkeley. Both cases, sign/overpass overhead.

teslarama | 22 juni 2019

@jjgunn..yes. There is FastTrack sign.
There is one FastTrack sign under construction (the sign board is not fully setup...they just put the skeleton).
May be it is not able to fully decode that (compared to other freeway signs and overpasses).
I cross several overpasses on my commute from east bay to south problems any where else.
I'll pay some more attention on Monday and see.

David Trushin | 23 juni 2019

I've also suspected that this is more prevalent on overcast days. Then the sky is grayish white. While traveling on the highway on such a day, the braking was so annoying that I stopped using cruise control. I wish there was a way to disable the adaptive part until they fix it.

Phillip Flores | 28 juni 2019

I thought this was only me. It started a few updates ago and continues with 2019.20.21 I was headed from AZ to LA a few months ago and turned on just the cruise part. It took the command and seconds later the car slammed the brakes on with no one in front or to the side of me. I tried it again the same thing. I called Tesla they said to reboot I did and did not make a difference. I have noticed the indicator for cruise and autosteer on the screen keep turning off and on a lot. These are on roads I used in the past several times with cruise and Autopilot but not anymore. At this point just fix my cruise one of the functions on most cars can't be used by our expensive machines is nuts. Fix this already!!!

deanzsyclone | 29 juni 2019

This also happened to me, brand new X Raven, day two of driving, cruising on the 101frwy in California, 68mph, no vehicles in front of me for a thousand feet, no overpass, just me alone and wham, hard deceleration all the way down to 35mph on the freeway!!! OMG I thought what are you doing model x. Since seeing this happen a couple more times on the freeway I did happen to notice that one of the times the "indicated" speed limit on my front dash showed 35mph and I just waited and watched, did not interrupt the Tesla, and then noticed the "indicated" speed limit eventually go back up to 65mph. I suspect that when an adjacent slower road is next to the freeway and the GPS signal may be a bit on the inaccurate side may then get confused and the Tesla may think it's on the side road for just a moment, before correcting its location and speed and return to the properly posted speed limit for the road I'm actually on. I'm just glad I didn't get rear-ended, I can only imagine the headache that would of been for Tesla.

deanzsyclone | 29 juni 2019

I have the above theory based off of my Radar detector that gives me false alerts of red light cameras while driving on the freeway just as I'm passing over or very close to another road that actually does have a red light camera at that location.

tejami | 1 juli 2019

Was driving at 80 km and it suddenly stop had to takeover lucky to have my back. Reported to Tesla and the reply I got it has been more conscious I’m surprised that I can’t even use normal cruise control which is standard nowadays in most of the cars.
I hope Tesla fix of this issue ASAP as this has happened twice to me and I’m just wondering what if somebody dashes me from the back :(

teslarama | 2 juli 2019

@deanzsyclone...GPS speed limit is not an issue in my case.
It happens for me consistently on one particular spot (Bayarea, I-680 S bound, Mission blvd exit).
Today..I checked...GPS speed limit stays at 65 MPH as normal.
There is no car in front of overhead pass..nothing. Still slows down and then speeds up.
My colleague will try model3 with the same SW version 20.4.2 tomorrow.
Will see whether this is model X specific.
I have the same SW version 20.4.2.

jjgunn | 2 juli 2019

I mentioned in other threads

SF (city) 101 Southbound -- right about hospital curve. Speed Limit slows to about 45 & car slows/brakes. Sucks

teslarama | 3 juli 2019

Ok...we today tried model 3 with the same SW 20.4.2. Same problem in the same spot.
The SW version 2019.15 did not have this issue.
Still not able to figure out what the hell the it is seeing.
Probably dead people. In my case also...slows to 45.