2021 SR+ auto-braked for no reason today, help?

[ottermode]

My new 2021 Model 3 did a hard auto-brake for no reason about an hour ago and I can't figure out why. I've only driven the car a handful of times for very short distances (under 20 miles total now) so I'm really concerned about driving it now.

You can see after I pass the crossing I pretty much almost come to a complete stop for a second. My pregnant wife was in the car with me and this could have gone really bad, I'm honestly pretty upset that this happened. If this is the wrong place to post this please let me know.

https://i.imgur.com/EVLPHEi.mp4 Also want to add that this was not on autopilot.

 

[MasterC17]

My new 2021 Model 3 did a hard auto-brake for no reason about an hour ago and I can't figure out why. I've only driven the car a handful of times for very short distances (under 20 miles total now) so I'm really concerned about driving it now.

You can see after I pass the crossing I pretty much almost come to a complete stop for a second. My pregnant wife was in the car with me and this could have gone really bad, I'm honestly pretty upset that this happened. If this is the wrong place to post this please let me know.

https://i.imgur.com/EVLPHEi.mp4 Also want to add that this was not on autopilot.

Were you using Traffic Aware Cruise Control? The cameras have some trouble with overpasses as shown in your video. The car is going to be overly conservative, so if it thought you were about to hit something it may slam the brakes. It happens pretty infrequently these days but it's certainly not unheard of. I highly doubt there is an issue. I think most of us just get used to having our foot over the go pedal to over-ride the automatic braking when it does this.

 

[ericem]

did look that dramatic IMO.

If you were paying attention you would have been accelerating and the auto braking would not have even done anything.

 

[designrs]

I’ve had the Model 3 SR+ with standard AP and I am actually surprised that this did not happen to me. My standard AP has been pretty much flawless. Yes, I do cover the accelerator occasionally for overpasses and shadows... and I do shut off AP in complicated situations, such as construction zones.

 

[designrs]

The environment in your video is very complex with overpasses, concrete walls and shadows. Lane markings are not great either. I would not be using AP or FSD in that environment.

 

[jjrandorin]

Search TMC for the term "phantom braking" and you will read quite a bit about this topic. Take a look at this thread below, but ignore any of the posts around grammar. I linked a few threads there regarding phantom braking that you can read.

Auto Pilot unexpectedly breaking?

 

[ottermode]

Were you using Traffic Aware Cruise Control? The cameras have some trouble with overpasses as shown in your video. The car is going to be overly conservative, so if it thought you were about to hit something it may slam the brakes. It happens pretty infrequently these days but it's certainly not unheard of. I highly doubt there is an issue. I think most of us just get used to having our foot over the go pedal to over-ride the automatic braking when it does this.

I was not using any AP or cruise control, my foot was on the accelerator the whole time (though not pressing super hard) and it braked very hard (it doesn't look that way on camera but it went from ~20-25 to almost dead stop in l second.

I’ve had the Model 3 SR+ with standard AP and I am actually surprised that this did not happen to me. My standard AP has been pretty much flawless. Yes, I do cover the accelerator occasionally for overpasses and shadows... and I do shut off AP in complicated situations, such as construction zones.

I wasn't using AP is the thing, if I was I would just chalk it up as a quirk of the system

The environment in your video is very complex with overpasses, concrete walls and shadows. Lane markings are not great either. I would not be using AP or FSD in that environment.

Wasn't on AP.

Search TMC for the term "phantom braking" and you will read quite a bit about this topic. Take a look at this thread below, but ignore any of the posts around grammar. I linked a few threads there regarding phantom braking that you can read.

Auto Pilot unexpectedly breaking?

I did look up phantom braking but most responses have said its during auto pilot or adaptive cruise control (both of which I did not use). Does autobraking occur on any other settings?

 

[jjrandorin]

the only other time I know the car attempts to brake is if it thinks there is na obstacle and obstacle aware acceleration is on, or if it thinks a crash is imminent and it applies the brakes to slow down in an attempt to lessen damage in an accident.

I am not an expert on this though, but those Are the instances I know of. I didnt watch your video though, so I dont know your exact circumstances.

 

[stopcrazypp]

I did look up phantom braking but most responses have said its during auto pilot or adaptive cruise control (both of which I did not use). Does autobraking occur on any other settings?

Yes, there is a AEB (Automatic Emergency Braking) system (independent of autopilot) that many cars have now given NHTSA is pushing manufacturers to include it as standard equipment. It is always active. If that was what was activated, there should have been a chime and an alert on the dash when it activated. You are right that phantom braking is usually autopilot or ACC, and not this.

You can read the manual online, page 114 which describes it in detail. You can also disable the feature if you don't want to use it under Controls > Autopilot > Automatic Emergency Braking, but you have to disable it for every drive. There is also a related Obstacle-Aware Acceleration setting that mainly prevents the car from hitting walls from a standstill and that can be disabled permanently.

 

[drtimhill]

The environment in your video is very complex with overpasses, concrete walls and shadows. Lane markings are not great either. I would not be using AP or FSD in that environment.

The OP said nothing about using AP. This looks like a phantom braking issue, and these do occasionally happen.

Sadly any safety system will generate an occasional false positive, but that is the price you pay for the extra safety. You might want to read this post: Autopilot saved our lives

 

[momo3605]

That sucks. I had my SR+ for over 18 months and never had a phantom brake off autopilot. Usually it will start beeping that there is an obstacle ahead of you before it resorts to braking.

One thing I would suggest is changing the collision warning from early to medium. The early one would beep way too much even if I know I was safe.