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

Phantom braking in my new Model Y

This site may earn commission on affiliate links.
So sorry to hear that. Unfortunately, I lived with that for a long time when it was much worse. There is hope though. My Model 3 I got just a few weeks ago is TeslaVision only and no issues so far in close to 1k miles.

I will say that the PB issues in my Y were much better the last few months. The first 7 months of ownership were horrid though. I lost count of how many times I was thinking about selling it even though I loved it otherwise. I did sell it finally but by then it was much better but still room for improvement. I'd still take a dumb cruise at this point as I am so gun shy of TACC on any of my Teslas.
 
Another 2021.x user here: 2021.43.102 (on a 2-week-old myLR). Did a 475+475 mile trip , with 355 miles of freeway then 120 miles (2.25 hours.) of 2-lane road at the far-end, then the reverse order coming home. We were using only TACC (no AP). We had zero problems on freeway or divided highway, and zero problems if we followed another vehicle at following distance.

For the 120 miles of 2-lane each way, when there was nobody behind us, for a while we just let TACC do its thing. It seemed like about 2/3 of the time when there was a semi in the oncoming lane, the Tesla would slow by at-least 5mph ("phantom slowing"?). Maybe 1/4 of the time, it included the three warning chimes and strong slowing. One time the speedometer dropped by 29mph. Another time by 34mph (from 72mph to 38mph). It seemed like somebody was rolling four 6-sided dice, and slowing the car by "4d6" mph.

Since we're running a 2021.x software release, I have no idea if this behavior is representative of anything.
 
Last edited:
  • Like
Reactions: DrGriz
Another 2021.x user here: 2021.43.102 (on a 2-week-old myLR). Did a 475+475 mile trip , with 355 miles of freeway then 120 miles (2.25 hours.) of 2-lane road at the far-end, then the reverse order coming home. We were using only TACC (no AP). We had zero problems on freeway or divided highway, and zero problems if we followed another vehicle at following distance.

For the 120 miles of 2-lane each way, when there was nobody behind us, for a while we just let TACC do its thing. It seemed like about 2/3 of the time when there was a semi in the oncoming lane, the Tesla would slow by at-least 5mph ("phantom slowing"?). Maybe 1/4 of the time, it included the three warning chimes and strong slowing. One time the speedometer dropped by 29mph. Another time by 34mph (from 72mph to 38mph). It seemed like somebody was rolling four 6-sided dice, and slowing the car by "4d6" mph.

Since we're running a 2021.x software release, I have no idea if this behavior is representative of anything.
400 miles of almost exclusively 2 lane driving over the last 2 days. We found that turning off (not just disabling) Autosteer virtually (but not 100%) eliminated the slowdowns. Also, white vehicles, usually trucks, were the cause of 95% of the slowdowns that occurred no matter what. Didn't have to worry about other vehicles other than one large orange semi. Blue, black, yellow, red, green, brown, no problem.
 
  • Informative
Reactions: sckor
So if TACC is ON, and Autosteer is OFF, does that make the car keep certain distance from the car in front up to max speed but without steering control?

So this is kinda like just one "click down" mode from driver's perspective with everything on but without the PB?

This is confusing. lol.
 
Interestingly, I have a 2019 model three and I experienced the strange phantom braking issue today when a tractor trailer came down the opposing side of the 2 lane road I was on today.

Now it wasn’t crazy Phantom breaking but the card did slow itself down. I was in full self drive mode. However, I had my foot on the gas because traffic was going more than 5 miles an hour over the speed limit.

As such the car didn’t have the opportunity to slam on the brakes… which would definitely have been bad given the amount of traffic behind me.
 
Someone seems to have noticed a large improvement in TACC PB behavior with the recent 2022.4.5.17 update:

I updated to that version yesterday, but have not tried out TACC yet. Will be interesting to see if this is the "one" that largely fixes the issue. 🤞
I've noticed the same with 2022.4.5.17 over the past few days. It's great to see others finding the same improvement, so maybe I'm not just imagining it. My 21 MYP has trouble every morning in the dark in 2 scenarios. The first is oncoming headlights when there is no car to follow in front of me. This almost always triggered hard braking and FCW on 50mph single-lane-each-way farm roads. The second scenario is a local 25mph town road with cars parked in the shoulder. The proximity of the parked cars on the side would intermittently trigger sudden hard braking. BOTH of these scenarios have been braking-free these past 2 days since 2022.4.5.17, which had never happened before.
 
So I got back from the same roadtrip I do every few weeks... This time the only issue I had, was oncoming trains. I got a message saying speed was reduced because of approaching emergency vehicles, lol... The trains did have flashing white lights on the front....
I had something similar with lights on an overpass. A few miles down the road, I passed a police car that had its lights on and was stopped on the side of the road. It didn't warn for that one. I think that feature was really premature.
 
  • Disagree
Reactions: WhiteWi
I had something similar with lights on an overpass. A few miles down the road, I passed a police car that had its lights on and was stopped on the side of the road. It didn't warn for that one. I think that feature was really premature.
YEah, the train thing caught me off gaurd, becuase I was on a freeway with 70mph speed limits, and the train tracks were on the side. I've driven that section of freeway a bajillion times when an oncoming train was approaching at night (very busy train corridor), and never had this happen... So I think it's a new thing... Since I've had way fewer actual phantom brake events with the recent updates, I suppose I'll take the trade, lol...
 
  • Like
  • Informative
Reactions: jsight and DrGriz
I just took delivery of my M3 last week…so far, i find the Cruise and AP to be, essentially, unusable. The amount of aggressive braking for no apparent reason when driving in traffic is just unsafe. I haven’t had the brakes “lock up” yet, but I’ll be driving and , out of nowhere, it will start to slow quite abruptly...to the point I am really concerned that someone behind me might run into me. I’ve stopped using it when cars are following behind.

It simply has to be resolved.…its REALLY bad!