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Sudden Braking

voltage

Member
Feb 14, 2016
175
256
Raleigh, NC
Hi. I was driving on the highway yesterday using TACC, not autopilot. Speed was set at 69MPH. My car suddenly braked very abrupt to around 30MPH. There was nothing in front of the car. It scared the sh*t out of me and my wife. Never had that happen before. I'm wondering if there is some issue and it's worth taking in for service or it's just a software glitch. Anyone else experience this? Good thing it was light traffic or likely would have been rear ended. It's a Model S Performance 2020 that I bought last December. I love the car, but this completely caught me off guard.
 
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Reactions: Lubestaff

DerbyDave

Member
Jul 2, 2020
801
446
Kentucky
Happens to me daily. I am hoping the rewrite FSD will eliminate the phantom braking. Other cars' advanced dynamic cruise control systems do not do this. I can't figure out why basic driving in a lane without phantom braking is so difficult for Tesla to master. I just want to continue without sudden interruption. Time will tell.
 

Ostrichsak

Active Member
Sep 6, 2018
3,487
3,516
Colorado, USA
Happens to me daily. I am hoping the rewrite FSD will eliminate the phantom braking. Other cars' advanced dynamic cruise control systems do not do this. I can't figure out why basic driving in a lane without phantom braking is so difficult for Tesla to master. I just want to continue without sudden interruption. Time will tell.
It's one of the reasons I still own AP1 cars.
 

voltage

Member
Feb 14, 2016
175
256
Raleigh, NC
Thanks for confirming. I won’t be using TACC anymore. Bummer. To be honest I hate the whole self driving concept and this just is one more reason. Having old school cruise control would be nice.
 

tcoombes

Supporting Member
Jan 22, 2018
1,068
3,374
Northern California
I experienced phantom braking that could be reproduced in the same location and driving conditions until some of the new software releases over the last couple of months. I have not experienced any phantom braking recently and I am currently on 2020.44.25.
 

Ostrichsak

Active Member
Sep 6, 2018
3,487
3,516
Colorado, USA
Thanks for confirming. I won’t be using TACC anymore. Bummer. To be honest I hate the whole self driving concept and this just is one more reason. Having old school cruise control would be nice.

If you don't want to be a beta tester I completely understand given what you're putting at risk. That said and in the interest of fairness, they are evolving the system still pretty regularly. As good as AP1 is on the basic functions (read: no phantom braking) it's sort of frozen in time from that aspect. For better or worse, it won't change.

I've read that the phantom braking issue on the newer systems is being addressed and has improved somewhat. I can't speak from personal experience but I hope they get it ironed out sooner than later because I wouldn't mind having some of the features the newer systems offer once I feel it's on-par with what my aging AP1 system can do. I'm sure it's a matter of time before it's as smooth as my ancient AP1 car. I'm not trying to talk you out of opting out of being a beta tester but if you do I would advise that you check back in from time to time to see if they correct the issue at some point. These features, when they work, are quite useful and tend to add much safety to the overall driving experience.
 

makaylaking59

New Member
Nov 30, 2020
1
0
Menifee, CA
My car suddenly slammed on the brakes when I was driving in the fast lane on the freeway! I had to immediately step on the excelerator to prevent being rear ended. It scared the crap out of me! This was the second time my car brakes for no reason.
 

Snerruc

Member
Apr 16, 2016
984
1,388
Palm Bay
I’ve had two Tesla’s. Never had phantom braking on either car until the current update. Now it’s happening on Autopilot most times trips. Nothing around that might cause it.
 

cityhpper

Member
Aug 14, 2020
16
4
Agder, Norway
Frequent phantom braking here as well. No cure in the latest sw-versions. The car seems confused by wrong/missing speed limits in the map data, even if it now does a pretty good job at rading speed limit signs. It's also easily scared by shadows (e.g. entering and inside tunnels) and low sun.
We're at map data from 2019 although we had 2020 maps for two weeks in June (was pulled again by Tesla). Which version are you at, in the US?
 

RUK MINI

Member
Mar 24, 2020
5
0
Racine, WI
Phantom breaking was a regular feature in my 2019 MS LR up until about 4 months ago at predictable locations in freeways around me. Despite that I continued using TACC with care to see if the periodic software updates helped.

Now I am on 2020.48.10; and I can say that it has dropped by about 75%. When I am on longer trips I still engage TACC but "sitting at the edge of my seat". And it happens about every 50-75 miles apparently for no reason.

It is extremely disappointing that the world's most technologically advanced car company cannot eliminate this irritating issue, while others (e.g. Cadillac) have no such problem.
 

R2019M3

New Member
May 10, 2019
3
1
Huntley, Il
Had several occurrences on I-90 between South Beloit. IL. and Madison, WI. At first, thought it was because of older construction zones. But in all cases, coast was clear. Have a shop appointment early April. Maybe a fix around?? Really shakes you up when speed drops from 70 to 45!!
 

DerbyDave

Member
Jul 2, 2020
801
446
Kentucky
Had several occurrences on I-90 between South Beloit. IL. and Madison, WI. At first, thought it was because of older construction zones. But in all cases, coast was clear. Have a shop appointment early April. Maybe a fix around?? Really shakes you up when speed drops from 70 to 45!!
No fix. Hopefully the complete rewrite of FSD will fix this, whenever we are allowed to use it. I can't use FSD often because of this safety issue. My car brakes suddenly with no shadows across the road, no going under bridge or overhead signs, no reason. Sometimes I think it is bad map data speed limit information, but the current version of the software reads the speed limit signs. Unless map data overides the visual speed limit, who knows what causes this "feature". Tesla is too much reliant on visual control of the FSD. It needs to use the radar to confirm if something is in front of it, and not rely 100% on visual information. In the past 2 years, missing tractor trailers' overturned across the interstate in at least two instances is not satisfactory, nor is slamming on the brakes (phantom braking) for no reason.
 

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