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Serious Issue with our 2021 Model 3 - Reported to TSB

S4WRXTTCS

Well-Known Member
May 3, 2015
6,650
8,100
Snohomish, WA
I got a call today from an investigator with regards to my complaint about phantom braking. Unfortunately I was in meetings all day but I'll call them back tomorrow.
One of the things I find odd about what you're reporting is you have it happening on what appears to be an divided highway.

Most of the PB with Tesla Vision seems to be occurring on undivided highway (based on what I've read on TMC).

When you talk to the investigator make sure they know what road type its happening on. Whether its divided or undivided. It's also important to point out that its with Adaptive Cruise Control as the car doesn't have conventional cruise control.

In my experience I have occasional PB while on divided roadways while under AP or TACC (TACC is tesla's adaptive cruise control). I do find it problematic, but not nearly to the level that people are reporting with undivided roadways.

There is something about undivided road ways that causes Tesla Vision issues.

I don't use adaptive cruise control or AP on undivided roadways.
 
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S4WRXTTCS

Well-Known Member
May 3, 2015
6,650
8,100
Snohomish, WA
I’m on FSD Beta 10.10.2 and the highway driving is vastly improved for me. The only issue I noticed is when passing over interchanges, sometime the posted speed limit will drop to 45mph, thus applying the brakes. This is mostly gone for me now, but it has happened.
If you turn off FSD Beta this will go away.

I'm probably going to create two profiles where one profile has FSD Beta enabled, and the other doesn't.
 

Sam1

Active Member
Sep 11, 2019
1,625
1,718
NV
BTW

If you reported it to Tesla, but didn't report it to the NTSB, you really didn't report it.
That's not the way it works. You report them to the manufacturer to see if it's an issue with your product, then if they say there's no issue - that is when you file a report with the NTSB (if that's who regulates whatever issue you're having).
 
My US Model 3 user manual clearly states that TACC is a beta feature and has a clearly displayed warning that TACC "may occasionally cause Model 3 to brake when not required or when you are not expecting it."

Assuming that the user manual for your car in your country has the same, or similar language, you might want to point out to the investigator that Tesla did warn you about this issue prior to your decision to use TACC.
 
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As said many times before, if your experience is bad, document a specific example, preferably supported by dashcam video, and sent in a report to the NTSB.

That is the ONLY way this situation will get fixed.
You mean NHTSA?
That's not the way it works. You report them to the manufacturer to see if it's an issue with your product, then if they say there's no issue - that is when you file a report with the NTSB (if that's who regulates whatever issue you're having).
Is there a reference or document from Tesla or NHTSA that says to do that and in that order? These don't.

Model 3 Owner's Manual | Tesla doesn't say that either. That said, I generally agree w/reporting to the automaker + NHTSA.

In some cases (not always possible/applicable), it might make sense to report after the issue has been resolved (e.g. safety issue developed and resolution was to replace parts x, y and z that broke) or an attempt has been made to resolve it first.
 
My US Model 3 user manual clearly states that TACC is a beta feature and has a clearly displayed warning that TACC "may occasionally cause Model 3 to brake when not required or when you are not expecting it."

Assuming that the user manual for your car in your country has the same, or similar language, you might want to point out to the investigator that Tesla did warn you about this issue prior to your decision to use TACC.
With regards to safety, this simply isn’t relevant. If the OEM is going to provide a feature, it must be inherently safe to use. With regards to the PB that many people, including myself, are experiencing, it simply isn’t safe. I had a PB issue where the car quite literally slammed on the brakes out of nowhere while using TACC. Had there been a car right behind me, there’s no way they could have kept from hitting me (turns out, the brakes on this car are phenomenal). You don’t get a pass as an OEM because you say “may occasionally cause Model 3 to brake when not required or when you are not expecting it." If it’s a safety hazard, it needs to be fixed or deactivated altogether. Hopefully, the NHTSA will force a solution.

To be clear, as far as pure driving goes, this car is great to drive but the automation features seem inferior to other vehicles I’ve owned. I had a BMW that was made over 15 years ago that had better auto wipers…i also prefer our Toyota’s auto high beams and auto climate, and it’s adaptive cruise control has never once slammed on the brakes without cause in the 5 + years we’ve owned the car.

I love the car, but It’s got to be fixed.
 
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Is phantom braking more likely to occur with vehicles having Tesla Vision cameras vs the radar system used on pre-2021 models?
No. My "radar system...pre-2021 model" is no longer using radar. My car is now vision-only, as part of FSD Beta. "Adaptive" features are significantly better since transitioning to vision-only. Some due to iterations of software non-FSD, some (likely) due to FSD Beta.
 
I have had multiple issues with phantom braking since i purchased my 22m3lr 2 months ago. this past weekend my wife and i went out to visit our son in Wichita KS. I probably had 3 of 4 braking incidences on the way to Wichita. Unfortunately is was dark on the way home. On a 2 lane highway at 65mph i had 30 to 40 phantom braking issues. This would happen if i was using cruise control or auto steer. probably 1 out of 5 cars or trucks would slow the car down. It was manageable if i kept my foot on the gas and powered through it, but the warning tones went off at lease 20 times. I have taken to car Tesla for service and was told that this was something that i need to get use to with the vehicle. i was told that this will get better with time. Like i said it is manageable during the day but down right scary at night. Does anyone have a solution to this problem?
thanks
 
I have the full automation package including the beta FSD. I had Radar but I guess it's no longer being used. There have been a few slow-downs (very seldom with brakes). But they are always "with a good reason", namely speed limit signs. Driving along at 70 MPH you pass a 55 MPH sign and the car obeys. What's funny is that most of the time it "knows better", but it's unpredictable. It's not obvious how the car should be reacting, so it's not easy to solve. And there are situations where the car over-reacts to potential hazards. Personally I prefer safe over sorry. The solution is to always be ready to adjust the top speed with the scroll wheel and use the accelerator to punch through. Once you're working around it ok, it's a minor nuisance at most.

I suspect TACC has the most problems, it's like half a brain, and I never use it. See if changing the safety parameters and using auto-steer gives better results.
 
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I have had multiple issues with phantom braking since i purchased my 22m3lr 2 months ago. this past weekend my wife and i went out to visit our son in Wichita KS. I probably had 3 of 4 braking incidences on the way to Wichita. Unfortunately is was dark on the way home. On a 2 lane highway at 65mph i had 30 to 40 phantom braking issues. This would happen if i was using cruise control or auto steer. probably 1 out of 5 cars or trucks would slow the car down. It was manageable if i kept my foot on the gas and powered through it, but the warning tones went off at lease 20 times. I have taken to car Tesla for service and was told that this was something that i need to get use to with the vehicle. i was told that this will get better with time. Like i said it is manageable during the day but down right scary at night. Does anyone have a solution to this problem?
thanks
The only solution available to you at this time is to not use TACC/AP on 2-lane roads until you get new software that improves the situation.
 
One of the things I find odd about what you're reporting is you have it happening on what appears to be an divided highway.
PB is definitely worse on 2 lane roads but I’ve experienced it on divided interstates as well.
My US Model 3 user manual clearly states that TACC is a beta feature and has a clearly displayed warning that TACC "may occasionally cause Model 3 to brake when not required or when you are not expecting it."
This is something that a lot of people don’t realize because it’s not shown anywhere on the screen like other beta features are and virtually no one reads the manual, especially for a ‘standard’ feature like cruise control. I still don‘t think it’s an excuse. As I’ve stated in another thread, other carmakers have been making adaptive cruise control systems for 10 years that work perfectly. Labeling it ‘beta’ as an excuse to give consumers a crappy system is a copout.
 
One of the things I find odd about what you're reporting is you have it happening on what appears to be an divided highway.

Most of the PB with Tesla Vision seems to be occurring on undivided highway (based on what I've read on TMC).

When you talk to the investigator make sure they know what road type its happening on. Whether its divided or undivided. It's also important to point out that its with Adaptive Cruise Control as the car doesn't have conventional cruise control.

In my experience I have occasional PB while on divided roadways while under AP or TACC (TACC is tesla's adaptive cruise control). I do find it problematic, but not nearly to the level that people are reporting with undivided roadways.

There is something about undivided road ways that causes Tesla Vision issues.

I don't use adaptive cruise control or AP on undivided roadways.
Yes, I was pretty descriptive in my original report. After talking to the inspector he let me know that there's a number of these incidents that have been reported. There's no pattern. They can happen day, night, clear, overcast, raining, four lane, two lane. Most are regen braking and not the forceful braking that I experienced.
 
Had Tesla come and take a look at the vehicle. We think we know what happened. The vehicle's autonomous driving system saw the vehicle's headlights being reflected in a shiny new road sign which caused the car to think a head-on collision was imminent. That potentially explains the hard braking I experienced and not the regen braking that we still experience daily when just using cruise. In fact it bothers my wife so much, she won't even let me use cruise control any longer. Haven't used autopilot since the original event. Just don't trust it anymore.
 
That's not the way it works. You report them to the manufacturer to see if it's an issue with your product, then if they say there's no issue - that is when you file a report with the NTSB (if that's who regulates whatever issue you're having).
That's not correct. It's good advice to report it to the manufacturer for sure but they are not an objective party. Read the book "Unsafe at any Speed" to get an idea of why what you are saying isn't a good strategy. Also, the recent Boeing fiasco reinforces that manufacturers have too much of a financial stake to be impartial.
 

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