Shudder when autopilot brakes

[ModlS3XY]

I've had my Model X for a year now and I absolutely love it. I've had one concern from the beginning but haven't asked about it before in the forums.
Anytime autopilot brakes hard, I hear a loud thud or a shudder if you will. Is this normal? Does this happen with all the cars when autopilot slams on the brakes?

Here's a video for your reference. The sound is more pronounced when you are in the car.

 

[ditzpro]

I have the same problem ..Funny , it only happens when on Autopilot ...The tech on an unrelated repair told me that it was probably the anti-locks /// I could not make it do it while he was at the house ... Next time I'm at the SC , I'll have them check it .
Mine started with 24K on the car ..

 

[Oldschool496]

I have the same problem ..Funny , it only happens when on Autopilot ...The tech on an unrelated repair told me that it was probably the anti-locks /// I could not make it do it while he was at the house ... Next time I'm at the SC , I'll have them check it .
Mine started with 24K on the car ..

Activate antilock yourself by braking hard to see if the sound is similar.

 

[ModlS3XY]

Activate antilock yourself by braking hard to see if the sound is similar.

I tried that. Don't hear the sound when I brake hard. The SC guy said that there is a play between the autopilot hardware and the brake and that's why you hear a thud when it brakes hard. He could be right but sometimes these guys just want to avoid as many repairs as possible and that's why I thought I'll check here.

 

[ditzpro]

My car never did this until recently .. So something is out of whack ...The sound on mine is loud and a definite shudder ..Also sounds like it's coming from the right front only ...

 

[mxnym]

Mine has always done this, only when the brake is activated (not during regen). I have always assumed the mechanical brake mechanism behind the pedal drops faster than the brake pedal itself and I subsequently hear the pedal hitting the mechanism when it "catches up" so I've never been concerned about it.

 

[ModlS3XY]

Mine has always done this, only when the brake is activated (not during regen). I have always assumed the mechanical brake mechanism behind the pedal drops faster than the brake pedal itself and I subsequently hear the pedal hitting the mechanism when it "catches up" so I've never been concerned about it.

This is exactly what I assumed was happening and just let it go. It has been happening on mine right from the beginning. I tried changing the follow distance (increased to 4, decreased to 1) but it still keeps happening.
If this is normal then why does it not happen on cars? That's what bothers me. I am worried that the mechanism hitting the brakes with that sound due to the travel it has will eventually damage something and that it will happen after the warranty expires.

 

[spectrum]

Mine does this too sometimes. 2018 100D.

 

[artc1688]

my 2019 MX does the same thing
yesterday also heard a loud "gearing" engagement sound when breaking hard while the autopilot is engaged
what I am curious about is the motor/transmission is supposed to a single gear..... why is this happening?

 

[mxnym]

my 2019 MX does the same thing
yesterday also heard a loud "gearing" engagement sound when breaking hard while the autopilot is engaged
what I am curious about is the motor/transmission is supposed to a single gear..... why is this happening?

You are definitely describing ABS. I believe ABS became mandatory for passenger cars in US as early as the late 1990's. ABS pumps the brakes for you sooner than you could and faster than you could to stop the car as soon as possible when a wheel would otherwise lock up. If your foot was on the pedal, you would have felt it pulsating.

 

[ModlS3XY]

You are definitely describing ABS. I believe ABS became mandatory for passenger cars in US as early as the late 1990's. ABS pumps the brakes for you sooner than you could and faster than you could to stop the car as soon as possible when a wheel would otherwise lock up. If your foot was on the pedal, you would have felt it pulsating.

You are right about the brake pedal pulsating. You can notice that in the video I posted in the first post on this thread.
If you're sure that it is the ABS, does it damage the vehicle in anyway by engaging frequently when in autopilot?

Also, I changed my follow distance from 2 to 4. That seems to have helped a little. Not as frequent.

 

[mxnym]

You are right about the brake pedal pulsating. You can notice that in the video I posted in the first post on this thread.
If you're sure that it is the ABS, does it damage the vehicle in anyway by engaging frequently when in autopilot?

Also, I changed my follow distance from 2 to 4. That seems to have helped a little. Not as frequent.

I don't have speakers, so I never looked at the video. When I read the OP, I must have stopped at thud. The thud and the shudder would be two different things of which I see we have now discussed both. I'm personally not worried about the thud, as I can't imagine the wear being significant enough to matter much given how robust brakes need to be to begin with (everything between the pedal and the wheels needs to be strong enough to stop a 6000 pound car when no power assist is available). Given how long ABS has been around, I wouldn't be worried about it from a wear perspective, either. I would be concerned about it being frequent, though, assuming it wasn't because people are constantly slamming on their brakes in front of me, as needing ABS for reasonable braking could indicate a problem with your tires (too worn or just crap) or brake pads/rotors (something causing them to catch when they shouldn't).

 

[lohboy]

Mine does this too sometimes. 2018 100D.

Same. It scares the crap out of me when Im not paying attention. I wonder if there is a fix?

 

[The Enterprise]

I have the same problem ..Funny , it only happens when on Autopilot ...The tech on an unrelated repair told me that it was probably the anti-locks /// I could not make it do it while he was at the house ... Next time I'm at the SC , I'll have them check it .
Mine started with 24K on the car ..

The SC told me today that’s “just the way it is and hopefully a future firmware would fix it”. . . Pity, as the car slows down beautifully under Traffic Aware Cruise Control (AP) when the car in front slows down to a complete stop. This shudder happens when TACC in AP is active and IMMEDIATELY AFTER I release the accelerator (I press the accelerator gently to get closer the the car in front of me).

 

[ModlS3XY]

The SC told me today that’s “just the way it is and hopefully a future firmware would fix it”. . . Pity, as the car slows down beautifully under Traffic Aware Cruise Control (AP) when the car in front slows down to a complete stop. This shudder happens when TACC in AP is active and IMMEDIATELY AFTER I release the accelerator (I press the accelerator gently to get closer the the car in front of me).

Are you sure that this happens only on AP and not when on TACC? Seen a few others mention this but haven't tested it myself. Let me consciously keep it on TACC and see if it never happens. Will at least be able to narrow it down to something.

 

[The Enterprise]

I turned off Automatic Emergency Braking and Obstacle-Aware Acceleration but this shudder still persists.

I will see if turning off the Forward Collision Warning helps... will post update later.

By the way, I am on v9.0 (2019.20.4.2 66625e9)

 

[MD JD]

800 miles now after a week driving. I confirmed that every time the car brakes hard during AP (say a car suddenly merges in my lane or the car suddenly thinks a parked car is right in front of me, etc.), there is an exactly the same kind of thud. Feels like ABS.

 

[ModlS3XY]

Lot of people here associate that sound with ABS. Wonder why no one in the SC has come up with that explanation....

 

[The Enterprise]

I turned off Automatic Emergency Braking and Obstacle-Aware Acceleration but this shudder still persists.

I will see if turning off the Forward Collision Warning helps... will post update later.

By the way, I am on v9.0 (2019.20.4.2 66625e9)

No reduction in the shudder. All the programer needs to do is when the car is at crawling speed, eg. less than 3km per hour when the car is creeping forwards at an intersection, allow the car to come to a stop by its own, like when AP is off.

Just upgraded to v2019.20.4.3 ... which appears to have same features as v2019.20.4.2.

 

[bdambrosio]

Aug 2018 MX - has done this on firm autopilot braking ever since new. Finally thought to search TeslaMotorsClub about it. Much relieved to find it so common. Kinda sounds to me like play in some mechanism taking up slack, ABS shudder is faster rate, isn't it?