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

Extreme phantom braking event tonight. No TACC or Autosteer

This site may earn commission on affiliate links.
Just FYI there are some spots on the 401 now where they are widening lanes from Milton to Mississauga that have messed up the car's interpretation of what road you're actually on. There's a weigh station that doesn't exist anymore that registers a 40km/hr speed limit for example. Autopilot will definitely react and TACC from my experience sometimes reacts and sometimes doesn't (maybe it also uses awareness of traffic speed of other cars around the vehicle...who knows).
Hello Everyone,

greets from Ontario.

regarding the phantom braking apperances, I have to join the subject. I have a 2022 M3LR, received last saturday 18. Dec. 2021.
Yesterday evening , I was driving the route London, ON to Toronto Airport and back on the 401 Highway. The complete drive was after sunset. The set speed in cruise control only (110 to 120 kmh) , without autosteering. I do not have FSD.

The phantom braking did appear really out of the blue cruising with 110kmh when getting close to off-ramps, being on the most right snail lane. It appears, as if the car sees the speed limit signs at the off ramp and tries to obey. I do not think the brakes were applied, but the energy recovery braking slowed the car down from 110 to 90, even the cruise control was changed to the setting of 80 kmph.
I believe, the auto AEB, as described in the previous mesage from rjpjink was set on as well.
I do have the FSD auto recognition activated though.

The auto steering, I guess its called here Autopilot (beta) was not activated as the feature does activate the high beams in a erratic fashion, which does not comply with my high beam behaviour, being more moderate with it. I really do not understand the matter behind this kind of operational need to take over the high beams for the auto pilot option. Is the car blind at night to operate to have the need for the high beams with this ?
There are certain exits around Montreal where I consistently see the TACC target speed drop suddenly even when I'm not taking the exit. Some of these changes in target speed are extremely short-lived, then the target subsequently changes back to my previous setting. I've reported these anomalies to Tesla with no response. It seems that the vehicle uses data from roadside signs but these are overlaid onto an existing speed limit database which contains some imperfections and discontinuities. I also surmise that some of these speed changes might be intended to prevent FSD from taking an exit too fast, although I really wish the car would let me be the driver because I'm in charge without FSD. As I understand it, these are not considered phantom braking events. That phenomenon is caused by another vehicle or overpass (or sometimes nothing at all) that Autopilot senses as a collision risk and it decelerates abruptly to avoid the perceived collision. My only experiences of this have been when passing a stopped truck that wasn't far enough onto the shoulder, and approaching an overpass on a downhill slope.
 
Hello Everyone,

greets from Ontario.

regarding the phantom braking apperances, I have to join the subject. I have a 2022 M3LR, received last saturday 18. Dec. 2021.
Yesterday evening , I was driving the route London, ON to Toronto Airport and back on the 401 Highway. The complete drive was after sunset. The set speed in cruise control only (110 to 120 kmh) , without autosteering. I do not have FSD.

The phantom braking did appear really out of the blue cruising with 110kmh when getting close to off-ramps, being on the most right snail lane. It appears, as if the car sees the speed limit signs at the off ramp and tries to obey. I do not think the brakes were applied, but the energy recovery braking slowed the car down from 110 to 90, even the cruise control was changed to the setting of 80 kmph.
I believe, the auto AEB, as described in the previous mesage from rjpjink was set on as well.
I do have the FSD auto recognition activated though.

The auto steering, I guess its called here Autopilot (beta) was not activated as the feature does activate the high beams in a erratic fashion, which does not comply with my high beam behaviour, being more moderate with it. I really do not understand the matter behind this kind of operational need to take over the high beams for the auto pilot option. Is the car blind at night to operate to have the need for the high beams with this ?
I did a road trip from DC to Chicago and return at night both ways in my 2021 MY in December. It never changed my headlight settings. I have noticed some roads and jurisdictions don’t allow for Cruise control or Autopilot to drive over a certain speed. Usually in towns and cities.
 
Safety scores are not just for crash tests. Collision avoidance and other safety features are also rated - that's why the quote mentions vehicle and pedestrian tests. All cars with collision avoidance will incorrectly brake sometimes, radar or not, Tesla or not. Not ideal, but hitting a car/stationary object in front of you is much less ideal. And the IIHS seems to think it's best to have this system in place, so I can assume they did a bit of research beyond YouTube and forums.

I know some people may be triggered by this, but... if someone hits you from behind then they are responsible since they followed too closely. Same as if you braked manually to avoid an actual obstacle. Even if the driver behind you doesn't see it, they are responsible for maintaining enough space to slow down safely. Also, it seems that most false braking events occur on undivided roads where autopilot is not technically supposed to be used yet. I have not had a problem with it, and the one time the car braked for a large chunk of ice in the road I simply pressed the accelerator and kept going.

It's definitely not perfect, but it's certainly better than having no safety systems in place. I'm not saying that people aren't having issues with it, even when used in a proper setting such as a divided highway, but suggesting it's more dangerous than no system at all is not accurate in my opinion (and IIHS's opinion). There is a reason that almost all new cars have these systems even though none of them are perfect. They will avoid many more accidents than they cause.
I think your last statement depends on the driver. A driver paying attention to the road and driving properly is better than any system out there right now.

Based on what I’m reading here it has made me question my order of the model y. My whole thing is that the situation was better with the radar. So why not use both the radar and vision? It’s always better to have more sensors than less especially if the sensors function better than just vision.
 
  • Like
Reactions: rjpjnk
I think your last statement depends on the driver. A driver paying attention to the road and driving properly is better than any system out there right now.

Based on what I’m reading here it has made me question my order of the model y. My whole thing is that the situation was better with the radar. So why not use both the radar and vision? It’s always better to have more sensors than less especially if the sensors function better than just vision.
More sensors does not necessarily mean a better system, especially when it comes to phantom braking. Conflicting sensor info means more braking. And Tesla has a bit more info than we do, so I would have to assume they know what they are doing. After all, they don’t want to get sued for reducing safety. And again, IIHS rated the new system and they think it improved.

If you are basing your info off of what people say online you will always get extreme cases - no one really posts when something just works. In my case it does just work.

This doesn’t replace the driver or take away any controls, it just assists when necessary. Usually a good driver won’t need assistance, sure, but once in a while every driver will. You can’t react as fast as emergency braking and you can’t predict every hazard while driving. These systems are there for a reason and it’s not just because some people are bad drivers.

I had the same worry about phantom braking as you. It was the one thing that I was unsure about. Luckily I still got the Y and have never had a problem with it. I don’t have radar btw. Yes, it can happen sometimes (based on other peoples experiences), but I think it gets over exaggerated. Even when it happens all driver inputs override the system. So if you are a good and attentive driver you can simply correct it. Almost every new car will have a similar system, so you can’t really avoid it. Go test drive if you haven’t and I would bet that you won’t experience it.
 
  • Like
Reactions: finman100
This is great news. I was not aware the IIHS rated the radarless system as improved compared to the radar based system. I would like to learn more about this. Can you provide a link?
CleanTechnica Article - "...only Model Ys built after April 2021 get the Top Safety Pick + award. Vehicles built before that date are still recommended, they just don’t have the “Plus” rating. IIHS says, Following a conversion to a camera only system, the standard front crash prevention system earns superior ratings in both the vehicle-to-vehicle and vehicle-to-pedestrian tests. The two available headlight systems earn good and acceptable ratings…” Separately, the standard front crash prevention system on 2021–22 Tesla Model 3 vehicles built after April 2021 also earns a superior rating in both crash avoidance tests”

IIHS article - "Following a conversion to a camera only system, the standard front crash prevention system earns superior ratings in both the vehicle-to-vehicle and vehicle-to-pedestrian tests."

IIHS ratings - "Award applies only to vehicles built after April 2021"
 
  • Like
Reactions: rjpjnk and Big Earl
Might be off topic - the other day a smart car (oxymoron) was changing lanes in front of me and I slammed on my brakes and the abs did it's job and I didn't receive any warning or auto braking. Is that something I should expect to happen?
Depends on the distance, closing speed, settings, and your control inputs (pedals/steering). If you already applied the brake enough it will not engage the automatic emergency brake or warning. If not then it will assist by braking harder. It’s important to note that the when it does engage, the emergency braking will most likely reduce an impact, but not avoid it unless you are at lower speeds. If you want a warning sooner take a look at your settings and select "early" for the forward collision warning if it’s not already selected.

More info on AEB from Tesla’s website:

"Automatic Emergency Braking does not apply the brakes, or stops applying the brakes, when:
  • You turn the steering wheel sharply.
  • You press and release the brake pedal while Automatic Emergency Braking is applying the brakes.
  • You accelerate hard while Automatic Emergency Braking is applying the brakes.
  • The vehicle, motorcycle, bicycle, or pedestrian is no longer detected ahead."
 
Great news. Thanks. I wonder why the older Model Y does not have as high a rating. I thought they disabled the radar and effectively run those as vision only as well, no?
I'm not positive, but I don't think they would go back and retest an older model year vehicle. Also, I think that radar cars still use radar unless they have fsd beta. It seems that the lower rating for radar models is due to a later warning. You can find more info on why the radar models were rated lower here - link. This particular test is the model 3, but it's the same system.
 
  • Like
  • Informative
Reactions: Big Earl and rjpjnk
Experienced my first "Autopilot is decreasing speed due to emergency vehicles" (or words to that effect) around dusk today. No idea what triggered it - I was heading north on a cloudy day, no flashing lights anywhere in sight. The car decelerated smoothly then went back to set speed after a few seconds.
 
Depends on the distance, closing speed, settings, and your control inputs (pedals/steering). If you already applied the brake enough it will not engage the automatic emergency brake or warning. If not then it will assist by braking harder. It’s important to note that the when it does engage, the emergency braking will most likely reduce an impact, but not avoid it unless you are at lower speeds. If you want a warning sooner take a look at your settings and select "early" for the forward collision warning if it’s not already selected.

More info on AEB from Tesla’s website:

"Automatic Emergency Braking does not apply the brakes, or stops applying the brakes, when:
  • You turn the steering wheel sharply.
  • You press and release the brake pedal while Automatic Emergency Braking is applying the brakes.
  • You accelerate hard while Automatic Emergency Braking is applying the brakes.
  • The vehicle, motorcycle, bicycle, or pedestrian is no longer detected ahead."
Thanks for the info. I'll take a look. The car really was on the side of me and I was about to pass it when it veered over. I didn't noticed it because I was trying to change lanes and all of sudden a car is right in front of my left fender. Luckily, I hit the brakes and the driver went back into the other lane. We going around 55 mph or so.
 
I had an "extreme phantom braking event" a few weeks ago (no seriously)

We were driving back up from a glamping trip down to the coast, on the interstate with no traffic for miles around when suddenly the brakes slammed on and everything in the back came flying forward

Ultimately it was ok though because after about a second the power came back with a vengeance . . .


. . . and everything flew back in to the trunk area
 
  • Like
Reactions: OxBrew
While not a phantom braking event the other night I was driving on the freeway and there was a larger vehicle in the next lane over and I felt the Tacc disengage and once passed reengaged. I rest my foot over the accelerator, so if it did brake I would have been able to react. I believe it was set for 70MPH.
 
While not a phantom braking event the other night I was driving on the freeway and there was a larger vehicle in the next lane over and I felt the Tacc disengage and once passed reengaged. I rest my foot over the accelerator, so if it did brake I would have been able to react. I believe it was set for 70MPH.

TACC won't disengage, then re-engage. However, if passing on the right and/or when passing with a very high speed differential, it will slow down some so that the speed differential between you and the other vehicle is lower. When it's reducing speed, it will show chevrons on the screen behind the vehicle you're passing.
 
Correction to my previous post on the vision/radar IIHS ratings- another member pointed out that I misinterpreted part of the info. Apparently the plus designation is only in place due to the headlights and "superior" is the rating level/grade rather than a comparative description, so they did not mean to say that the vision system itself was superior to radar - they were just rating it as superior which is the same rating as the radar model. That being said, the IIHS did seem to rate the vision better than radar in crash avoidance system test for the m3 as they rated the vision as "superior" and the radar as "advanced". I figured I would mention this here so nobody is potentially mislead by the incorrect info. I have read a few articles which made similar assumptions and then read IIHS info using the incorrect interpretation. Confusing stuff.
 
  • Like
Reactions: rjpjnk
TACC won't disengage, then re-engage. However, if passing on the right and/or when passing with a very high speed differential, it will slow down some so that the speed differential between you and the other vehicle is lower. When it's reducing speed, it will show chevrons on the screen behind the vehicle you're passing.
It felt like it disengaged. I was going freeway speeds as was the other vehicle and I felt it get off of the throttle and assumed it disengaged and reengaged. The times I disengaged TACC myself it felt the same but I didn't hear any chime, so you're probably right. The next time it happens I'll look on the screen and see what it shows. At the time, I really didn't pay any attention to it. For whatever reason, I find it hard to drive it at steady 70mph, so I use TACC to maintain that speed. I'm always at 65-66. Perhaps, it's my seating position.
 
Phantom Braking is real and out of control.
Last week, driving down interstate, TACC on. Nothing near me. Relaxed, happy, enjoying the car…….WHAM!
it slammed on the damn brakes so hard my wife and I were pushed into our Inertial reel locked seated belts, my hands came off the steering wheel and our heads were thrown forward. Almost instantly the brakes released, the car surges forward and our heads are flung back. A nerve was pinched in my neck during that whiplash and now my right shoulder muscle has been tensed up for days.
Absolute bullsh!t.

guess what? It happened again today.
This crap system needs to be fixed, auto braking disabled, or pulled off the market.
How can ANYBODY think this is OK?

 
Phantom Braking is real and out of control.
Last week, driving down interstate, TACC on. Nothing near me. Relaxed, happy, enjoying the car…….WHAM!
it slammed on the damn brakes so hard my wife and I were pushed into our Inertial reel locked seated belts, my hands came off the steering wheel and our heads were thrown forward. Almost instantly the brakes released, the car surges forward and our heads are flung back. A nerve was pinched in my neck during that whiplash and now my right shoulder muscle has been tensed up for days.
Absolute bullsh!t.

guess what? It happened again today.
This crap system needs to be fixed, auto braking disabled, or pulled off the market.
How can ANYBODY think this is OK?

Notify NHTSA about your experience and share any evidence if you have. You also forgot to mention about Thanks God no one was behind me.
 
  • Like
Reactions: watsongrg