Welcome to Tesla Motors Club
Discuss Tesla's Model S, Model 3, Model X, Model Y, Cybertruck, Roadster and More.
Register

Unhappy with phantom braking

This site may earn commission on affiliate links.
There are a variety of causes of phantom braking. What you're describing sounds like the mildest form - the car suddenly changes the set speed at a specific location, either because it saw a speed limit sign, or its map data indicated that it should slow down (supposedly, because other Teslas always slow down in that location, but that was from an old blog post so not sure whether that logic is still in the code). In these cases, I don't believe it uses the friction brakes, but suddenly starts to regen brake to get down to the new set speed. It's jarring but consistent. There's are two stretches of I-270 where it joins I-495 where I am that exhibit this behavior. I'll be cruising at 75 and it decides to change the set speed to 60mph for a few hundred feet. I expect that once they merge the new FSD stack into the NoA/Highway logic, a lot of this will go away. The traditional autopilot code is in need of a refresh because of a lot of this stuff that's been bolted on over time, and up until the most recent build of the FSD beta software, they hadn't even touched the highway logic.
Only thing I could do would be to drive the same route again and see if it re-occurs in the same places. I do know this, during one of the events, it braked so hard (NOT regenerative) that it scared the crud out of the person behind me and they were not even following close. I will keep an eye out for a software update and hope it takes at least some of the frequency out of this. Along with a visit to the repair center...
 
Gotcha. I was not going to rant to them, and agree that's good advice. I was going to talk about the camera issue and then "ask" if it maybe had something to do with the braking.

I think it does, in your case. I would tie the two together, like "I am experiencing random braking events when nothing is around, as well as the cameras reporting they are blocked and I have ensured they are clean. here is a picture of the message I receive".

With the additional information of the message you receive, I am guessing your experience is different than the "regular, known about" phantom braking, and you have an issue with your camera cabling or something.

Anyway, good luck with it!
 
We had a severe case of phantom braking at the weekend. Tesla have responded and basically can’t do anything at present. There is “allegedly” better firmware in the US but the U.K. software is behind (2021.12.27.7). I have officially reported the incident to the DVSA in the U.K. see Vehicle Safety Defect Report | DVSA
Yeah, no. I’m on 2021.24.3, more recent but no better than 2021.12.27.7. This is my 75th firmware update…same phantom braking. This is getting little-to-no resolution from Tesla after years of reporting. Until/unless Tesla gives us a dumb cruise control option, the only real choice is to not use it, at least with passengers. I hate it.
 
  • Like
Reactions: rt29781 and Dan D.
Same this has been discussed in other threads. Taking corners car will brake for no reason if there is a car object nearby, not phantom so to speak but shouldn’t be braking. Then just Thursday as an example I was driving home and the car refused to increase its speed from 54mph to 60mph where cruise control and autopilot was set. Nobody around or near me. It just holds its speed at 54. Never had that happen. I just sat there befuddled wondering what was keeping the stupid car from increasing up to set speed

We are getting near dumpster fire level with vision cars and lack of improvements and updates.

Then, the phantom braking for no reason mentioned amongst terrible depth perception while braking and stopping for slowing or stopped cars. I know city streets is coming later this year but my wife’s BMW and daughters VW handles stop and go traffic with its ACC way better than this M3 does. It is real smooth coming to a stop in traffic. And doesn’t follow 300 ft behind on its furthest setting like the Tesla. Then smash the brakes on as you look in the rear view expecting someone to hit you when it does it.
 
  • Like
Reactions: BrerBear and Dan D.
My car is a "Tesla Vision" car. No radar. The events happened on I-70. 3 lanes wide each direction and divided. Driving in middle lane. It occurred 4 times in an approximately 15 minute stretch in those conditions. (Then 2 other times spread out later.) Sunny day, slightly after 12:00 so no shadows. No debris on the road. No cars beside me. No overpasses in sight in any of the events. And, no curves coming up either. In every case, any car in front of me (in any lane) was at least 15 or more cars ahead. This is why this is so very disturbing to me. Each time it happened I scanned the road for anything it might have "seen". But folks, there was literally nothing but straight open concrete. The only thing I can think of is maybe "patch jobs" on the road surface. But around here, if it's going to stop for patch jobs, I'm never going to get anywhere!

I think I will report this to the service center and see what they say. I don't know if this is related or not, but I also keep getting messages that one or more (random) cameras are "blocked". Like I need to clean them or something. Car is spotless. Then the message goes away after awhile.

Software: 2021.3.106
I just got back from 10 hour road trip on all interstates for the most part. I have a 2021 Tesla 3 vision only and the above is my experience 100%. I bet I had 10-12 abrupt braking events just cruising in the center lane and all of the sudden it happens. Like the above posted my wife and I scanned around and nothing. Middle of the day and relatively flat. I also get the camera abstracted messages but mostly at night. No idea what that is or if it is related but very similar to above poster. I am seriously disappointed in this aspect of the car and never mind AP … I’d be fine with adaptive cruise even working while AP “bugs are worked out” but seems to not matter AP or not. I have a Honda Accord with adaptive cruise control for over 3 years prior to M3 and zero times did anything like this happen. Man do I hope we get a fix soon as it is souring an otherwise amazing first 3-4 months of ownership so far.
 
I only have a couple hundred miles on the car so far. Work from home and so far just some quick errands and have been REALLY enjoying the car. Wonderful "honeymoon". But today I took the car out on the highway and the honeymoon is OVER. What the heck is the deal with this car slamming on the dang brakes every few miles?!? I'm in Kansas and had a wide open 4 lane highway and there was not a freakin' car within 40 car lengths of me each time (front, side, nothing). And I'm talking throwing me forward SLAMMING on the brakes for absolutely no reason. In just a relatively short drive it scared the crud out of me a half dozen times. First time I thought I'd try the full auto-pilot thing. Blue lights showing, keeping me in my lane and BAMM - about threw me into the steering wheel and scared the crud out of the guy behind me. So I decided NOT to use that anymore and just went with the cruise control part and it did it several more times. Now I see all these posts about "phantom braking". Is this something I have to live with? Umm... NO! This is ridiculous.

Rant over. So is the honeymoon. There's no excuse for this.
I have a Model Y delivered in June and is radarless. On a road trip from Tulsa Oklahoma to Telluride Colorado, I experienced repeated rather frightening events of rapid deceleration. They occurred on two and four-lane highways in summer heat. One occurred with a car behind me that was forced to pass on my left, I rebooted the car before the return trip but found it was unchanged such that I did not use TACC or autopilot. My car was purchased with FSD. I also own a Ford F150 with adaptive cruise control and have never experienced anything like this. Also using Autopilot a notice came up on the bottom of the screen requesting a slight turning pressure to keep the Autopilot engaged. As a result, if I didn't see the notice the Autopilot cut out just when it should have executed a slight turn to keep me from running off the road. My hands were on the wheel the whole time. These two weaknesses have made me regret the FSD investment.
 
I have a radar-enabled Model Y (108xxx VIN) on 2021.12.25.11 with about 3,000 miles on it, and have only experienced a couple instances of unexplained breaking, after thousands of miles on I5 with autopilot.

It's really disappointing to hear that the vison only cars are worse.
 
I have a radar-enabled Model Y (108xxx VIN) on 2021.12.25.11 with about 3,000 miles on it, and have only experienced a couple instances of unexplained breaking, after thousands of miles on I5 with autopilot.

It's really disappointing to hear that the vision only cars are worse.
Both Musk and Karpathy have said removing radar will reduce phantom braking. Maybe they're wrong.

IMO a much bigger problem/difference for those of us outside of California is that the Tesla neural net has been overfit for California and especially for the Bay Area. You can see this in beta 9 FSD videos. The ones in California do much better than ones from other parts of the country. I believe there was a trip from SF to LA that had zero interventions. IIRC there were originally some problems with weather extremes not found near the Bay Area. For example, if Teslas were designed in the desert then I doubt they'd have glass roofs unless the roof came with a motorized sun shade.

I'm confident vision-only AP and FSD will be getting significantly better in the next few years. If performance plateaus out due to lack of radar then I think a radar retro-fit will become available. From everything I've seen I'd guess that vision-only can probably get 10 times better or more (in terms of miles per intervention) while removing radar was probably at least a wash. We're certainly seeing great strides in the beta 9 FSD even though it's vision-only on highways. According to Elon beta 10 should be vision-only everywhere. Beta 11 almost for sure.
 
... messages that one or more (random) cameras are "blocked"
I get this rarely, but it's usually early morning when it's very humid/rainy/foggy, probably a layer of dew on the lens. It goes away when (presumably) the dew evaporates.
If you get braking at, or around, certain locations, make sure you record it (scroll button "bug report - phantom braking") and record the dash cam (you'll have to email the video to them).
This will help service record the incident(s), they'll pass it on to engineering.
I'll be cruising at 75 and it decides to change the set speed to 60mph for a few hundred feet
Are you sure there's not a speed limit sign that the car is seeing, but you're not?

Random wild guess...if the road merges, is it possible the car thinks ... you're no longer on 495, you're now on 270...but since it only knows the speed limit on 495 and it hasn't seen a speed limit sign for the new road (270), it defaults to a lower highway speed, waiting to see a new sign alerting it to the new road's speed limit... (if that makes any sense).
How would car know the speed limit on a new road before seeing a sign?
Again, just a guess, but if this is a regular occurrence, I'd bet it has something to do with the road change
 
Last edited:
  • Like
Reactions: SlimJim
I doubt they're wrong about removing radar. But when you're literally creating a human-like brain inside of a car's on-board computer, you're going to have issues like this. It might take months or even years to fix. But I think they're on the brink of cracking this very hard problem. Stay patient.
IMO it doesn't matter if they crack the problem or not. Radar is just another way of "seeing" what's ahead of the car. I can't think of any logical reason to remove it other than cost savings and/or Elon's ego, and seeing how the radar unit costs $180 retail I think it's more of the latter. Think of it this way, how does it hurt to keep radar? Even if the car is vision only 99% of the time, radar can just be a fail safe. Vision thinks there's a car ahead, check radar output and see if it also sees the same thing.

If you work with computers you know image recognition algorithms are still not there yet and they're still easily fooled
 
  • Like
Reactions: linux-works
I think everyone agrees with OP, myself included, but it still blows my mind people spend $50K+ on a product without researching it. This problem has existed for years and there's tons of discussion about it on the internet.

In fact, it's not limited to Teslas. I've driven several rental cars from various manufacturers that also do some kind of "phantom braking".
 
I think everyone agrees with OP, myself included, but it still blows my mind people spend $50K+ on a product without researching it. This problem has existed for years and there's tons of discussion about it on the internet.

In fact, it's not limited to Teslas. I've driven several rental cars from various manufacturers that also do some kind of "phantom braking".

There are a ton of discussions on it, but a lot of those discussions aren't all that applicable to the new Radarless 3/Y.

Basically the radarless version has SW issues that need to get sorted out. It will likely follow the same path as before where initial builds of the SW will have phantom braking, and later builds will have significantly less.

Where most users will stop complaining, and it will just be a few here and there with out of the ordinary experiences.

As a radar based owner I stopped complaining about phantom braking a few months ago because it was reduced to where most of the occurrences I had were due to maps/navigation. They still annoy me because Tesla doesn't even have an effective reporting system for maps/navigation issues. So to me it doesn't look like Tesla is serious about solving those.

Tesla has to be serious about solving phantom braking with the vision based system as its core to their approach. So I would urge people to be patient, and maybe not use it for the next build or two until Tesla fixes it. Maybe do mass tweet to Elon to get him to acknowledge the problem with the Radarless cars.
 
IMO it doesn't matter if they crack the problem or not. Radar is just another way of "seeing" what's ahead of the car. I can't think of any logical reason to remove it other than cost savings and/or Elon's ego, and seeing how the radar unit costs $180 retail I think it's more of the latter. Think of it this way, how does it hurt to keep radar? Even if the car is vision only 99% of the time, radar can just be a fail safe. Vision thinks there's a car ahead, check radar output and see if it also sees the same thing.

If you work with computers you know image recognition algorithms are still not there yet and they're still easily fooled

The only reason that makes sense is it was removed prematurely due to supply constraints. The IC shortage is making a complete mess of things, and manufactures are resorting to desperate measures.

They removed it on vehicles that sold in volume, and in North America where they could remove it without much push back from regulatory.

As to why they were going to remove it I think it comes down to the fact that it was insufficient for the job.

They couldn't go with an improved radar because they already promised people FSD with their current car, and upgrading the radar would have been expensive and embarrassing. The Elon's ego aspect.

So the easiest thing was to simply give up on merging data from the Radar and the Vision for all the FSD stuff.

I imagine they're going to do exactly what you suggest in using radar in a very reduced form somehow when its available. I don't expect them to add the radar back when supply is no longer constrained. In fact I expect them to remove the radar across the board from new vehicles.

Going forwards its vision.

As to AI vision easily fooled I agree with you, but that's what the human behind the wheel is for.

Of course the human has issues as well. Like today I was behind a lady who suddenly slowed for a green light. At first I thought she was confused and she was debating getting into the turn lane. After second or two she finally got going again, but by then the light turned yellow so I had to stop. While I was stopped I realized she was looking at a dad and a kid dressed up in some Halloween costume on the sidewalk. So I'm not sure we want humans to be teaching computers what to stop for.
 
  • Like
Reactions: linux-works