2021 Model S Plaid Brake Failure - At lower speeds.

[BlueMissile]

So far, I haven't been able to find anything yet anywhere regarding this.

Problem: 2021 Model S Plaid Brake Failure - At lower speeds.

My wife was driving the Plaid home for me and on a left turn, the brakes failed causing a collision with a curb and sidewalk in a neighborhood. After going around another turn, the brake failure occurred a second time. Also, during all of this the seatbelt failed to lock.

Thoughts?


Videos Below:

1st Brake Failure:

Post will follow with video of 2nd Brake Failure.

 

[BlueMissile]

Here is the footage of the 2nd Brake Failure:

 

[mswlogo]

So far, I haven't been able to find anything yet anywhere regarding this.

Problem: 2021 Model S Plaid Brake Failure - At lower speeds.

My wife was driving the Plaid home for me and on a left turn, the brakes failed causing a collision with a curb and sidewalk in a neighborhood. After going around another turn, the brake failure occurred a second time. Also, during all of this the seatbelt failed to lock.

Thoughts?


Videos Below:

1st Brake Failure:

Post will follow with video of 2nd Brake Failure.

Not accusing your wife of anything but two things seem odd.

At those speeds, and a car that could take that turn probable at 50 mph, why did she drive into the curb?

If brakes are failing why did she keep going? Especially through your own neighborhood.

Are sure this isn’t a Yoke issue?

 

[BlueMissile]

Not accusing your wife of anything but two things seem odd.

At those speeds, and a car that could take that turn probable at 50 mph, why did she drive into the curb?

If brakes are failing why did she keep going? Especially through your own neighborhood.

Are sure this isn’t a Yoke issue?

The cars speed was at roughly 20-30 mph. Brake was pushed to the floor only to receive a clicking noise.

We live down the street where the second bake failure happened, she was just trying to get the car there at that point.

Confident it isn’t a yoke issue at this point, both car and user wise.

 

[Ohmster]

So far, I haven't been able to find anything yet anywhere regarding this.

Problem: 2021 Model S Plaid Brake Failure - At lower speeds.

My wife was driving the Plaid home for me and on a left turn, the brakes failed causing a collision with a curb and sidewalk in a neighborhood. After going around another turn, the brake failure occurred a second time. Also, during all of this the seatbelt failed to lock.

Thoughts?


Videos Below:

1st Brake Failure:

Post will follow with video of 2nd Brake Failure.

Brake failure is >0% probability. But not by much.

Possible. But not probable.

 

[BlueMissile]

Brake failure is >0% probability. But not by much.

Possible. But not probable.

The first SC speculated it being the recall for the Retrofit of the Wake-Up Wire.

After talking to them I then went to my normal SC in town. After hearing what happened and me being able to provide the video, they wanted the car towed to them. Tesla Roadside had it towed in that night, and the next morning when I went in to pickup my loaner, they said that engineers for Tesla and the brake systems specifically are now involved.

I’m thinking it was something with the computer failing or being “half awake” as the one tech said.

Either way, the brakes should have responded when being pushed in, right?

 

[Ohmster]

The first SC speculated it being the recall for the Retrofit of the Wake-Up Wire.

After talking to them I then went to my normal SC in town. After hearing what happened and me being able to provide the video, they wanted the car towed to them. Tesla Roadside had it towed in that night, and the next morning when I went in to pickup my loaner, they said that engineers for Tesla and the brake systems specifically are now involved.

I’m thinking it was something with the computer failing or being “half awake” as the one tech said.

Either way, the brakes should have responded when being pushed in, right?

Wow. Apologies for minimizing this. I’m glad your wife is ok and Tesla is looking into it.

 

[BlueMissile]

Wow. Apologies for minimizing this. I’m glad your wife is ok and Tesla is looking into it.

My biggest concern with it was the seatbelt didn’t lock at the same time. My wife is pregnant as well, so the concern is higher. However, my bottom line is that this doesn’t happen to someone else.

I’m hoping that Tesla can resolve it soon, but I have no idea at the moment.

Has anyone else seen or experienced anything similar?

 

[DerbyDave]

It looks like it didn't even slow down. Did regenerative braking also fail?

 

[DerbyDave]

Also, please report this to the NHTSA so they can see if a recall is warranted. It is an easy process. Report a Safety Problem | NHTSA

 

[bedoig]

Looks like the car was leaking (brake?) fluid at around 1 second in the first video before the first impact? Even more visible immediately after that first impact. Does your wife recall any notifications on the screen, or did you happen to check the notification log when you got it home? Glad she's safe (and the baby!) and hope everything gets fixed for you.

 

[MorrisonHiker]

Not accusing your wife of anything but two things seem odd.

At those speeds, and a car that could take that turn probable at 50 mph, why did she drive into the curb?

If brakes are failing why did she keep going? Especially through your own neighborhood.

Are sure this isn’t a Yoke issue?

I noticed there also wasn't much braking when the car ran the stop sign.

The cars speed was at roughly 20-30 mph. Brake was pushed to the floor only to receive a clicking noise.

We live down the street where the second bake failure happened, she was just trying to get the car there at that point.

Confident it isn’t a yoke issue at this point, both car and user wise.

If the brakes weren't working, why didn't she just take her foot off the accelerator? With no foot on the accelerator, regen would've kicked in and the car should've stopped right away since there's no longer any creep mode.

Looks like the car was leaking (brake?) fluid at around 1 second in the first video before the first impact? Even more visible immediately after that first impact. Does your wife recall any notifications on the screen, or did you happen to check the notification log when you got it home? Glad she's safe (and the baby!) and hope everything gets fixed for you.

There are also fresh tread marks before the car even hits the curb. Maybe the car just visited a car wash and it's still wet and dripping water?

 

[BlueMissile]

It looks like it didn't even slow down. Did regenerative braking also fail?

The car's charge was full that morning. So at the time it's charge should have been about 360 and maybe even above 370 when she picked it up from my work. Regenerative braking would have been reduced either way. However. there was an error code for something regarding regenerative braking not working.

Also, please report this to the NHTSA so they can see if a recall is warranted. It is an easy process. Report a Safety Problem | NHTSA

I will look into this. Is it worth it?

Looks like the car was leaking (brake?) fluid at around 1 second in the first video before the first impact? Even more visible immediately after that first impact. Does your wife recall any notifications on the screen, or did you happen to check the notification log when you got it home? Glad she's safe (and the baby!) and hope everything gets fixed for you.

The car was recently washed right before it. There is also construction going on down one of the streets. The water drops that you are seeing I believe was water runoff from the car. I've noticed on the Plaids, it likes to build up inside the shiny black pieces of trim.

I noticed there also wasn't much braking when the car ran the stop sign.


If the brakes weren't working, why didn't she just take her foot off the accelerator? With no foot on the accelerator, regen would've kicked in and the car should've stopped right away since there's no longer any creep mode.


There are also fresh tread marks before the car even hits the curb. Maybe the car just visited a car wash and it's still wet and dripping water?

There was no response of braking at all until she reaches right in front of the house. The car free rolled through the stop sign (thankfully not a busy street ever).

Taking the foot off of the accelerator, the car still was free rolling. The state of charge was too high for regenerative braking; as well as, the error codes saying it. There also was an error code regarding the "Hold" not working. All the fail safes for the Plaid not being able to move on it's own, failed.

The car did recently visit the car wash prior. I would say within the hour prior. That is what all the water is that is dripping. I believe the water tread marks are from going over a where the street sweepers have been going or the gutter water from the sprinklers. I'm still leaning towards the car not being fully awake from the going in and out of the different doors at the car wash.

 

[Gninoked]

The car's charge was full that morning. So at the time it's charge should have been about 360 and maybe even above 370 when she picked it up from my work. Regenerative braking would have been reduced either way. However. there was an error code for something regarding regenerative braking not working.


I will look into this. Is it worth it?


The car was recently washed right before it. There is also construction going on down one of the streets. The water drops that you are seeing I believe was water runoff from the car. I've noticed on the Plaids, it likes to build up inside the shiny black pieces of trim.


There was no response of braking at all until she reaches right in front of the house. The car free rolled through the stop sign (thankfully not a busy street ever).

Taking the foot off of the accelerator, the car still was free rolling. The state of charge was too high for regenerative braking; as well as, the error codes saying it. There also was an error code regarding the "Hold" not working. All the fail safes for the Plaid not being able to move on it's own, failed.

The car did recently visit the car wash prior. I would say within the hour prior. That is what all the water is that is dripping. I believe the water tread marks are from going over a where the street sweepers have been going or the gutter water from the sprinklers. I'm still leaning towards the car not being fully awake from the going in and out of the different doors at the car wash.

The Plaid has hydraulic brakes like most cars from the last ~50+ years. The assist is electric (Bosch iBoost) rather than vacuum and of course the car does slow down under most circumstances via regen too, but the car does not blend the brakes electronically like many other EVs and Hybrids. If you push the pedal it is hydraulically sent straight to the calipers. The car's high voltage and 12V battery can both be 100% dead and the brakes will still work, but they will not be assisted (just like a ICE car that isn't running to produce vacuum to power the assist.)

Someone who has never had the assist go out on them might not realize how hard you have to hit the brakes when it is gone to slow down. To that person it would feel like the car has 'no brakes.'

There are other possibilities but they are even more unlikely - piston seals or lines can go bad but usually they would have to be really old or physically damaged by something. The front and rear brakes have separate loops from the master cyl for this reason, and both would have to go down OR the master cyl itself would have to fail catastrophically. It's also possible to run out of fluid, but again something would have to be leaking profusely for that to happen on a newish car, and that would be from some sort of physical damage.

Very curious what the final answer is!

Edit: Just realized you said that there was an error code for the Hold not working - that is done by the iBoost system, so I'm guessing that failed and she had brakes but they were no longer assisted and she had no idea how hard you have to push to get the car to slow in that case.

 

[BlueMissile]

The Plaid has hydraulic brakes like most cars from the last ~50+ years. The assist is electric (Bosch iBoost) rather than vacuum and of course the car does slow down under most circumstances via regen too, but the car does not blend the brakes electronically like many other EVs and Hybrids. If you push the pedal it is hydraulically sent straight to the calipers. The car's high voltage and 12V battery can both be 100% dead and the brakes will still work, but they will not be assisted (just like a ICE car that isn't running to produce vacuum to power the assist.)

Someone who has never had the assist go out on them might not realize how hard you have to hit the brakes when it is gone to slow down. To that person it would feel like the car has 'no brakes.'

There are other possibilities but they are even more unlikely - piston seals or lines can go bad but usually they would have to be really old or physically damaged by something. The front and rear brakes have separate loops from the master cyl for this reason, and both would have to go down OR the master cyl itself would have to fail catastrophically. It's also possible to run out of fluid, but again something would have to be leaking profusely for that to happen on a newish car, and that would be from some sort of physical damage.

Very curious what the final answer is!

My wife said she pushed the pedal literally to floor and all that happened was a clicking sound. Do you make anything of that? This is our third current Tesla, so we're pretty familiar with some of the weird stuff that has or can happen with a Tesla. However, I have never experienced this problem until now.

 

[Gninoked]

My wife said she pushed the pedal literally to floor and all that happened was a clicking sound. Do you make anything of that? This is our third current Tesla, so we're pretty familiar with some of the weird stuff that has or can happen with a Tesla. However, I have never experienced this problem until now.

I slipped a stealth edit in there - based on the fact that it was saying that it wouldn't go into hold mode I'm thinking the iBoost died and she didn't realize how hard you have to push to get the car to slow down.

The clicking could be the ABS going off, that generally sounds like solenoids switching on and off. I will say that the ABS and iBoost work together to do hold mode. I have heard of other people having issues with wheel speed sensors getting installed improperly and worn through by suspension or the tires. In that case the ABS can exhibit all sorts of wierdness (like turning on when it doesn't need to.) But again the car should still slow down, just not as much as expected.

Coincidentally my wife's Ford Escape Hybrid just had a problem occur again with a bad wheel speed sensor for about the 3rd time - she also is getting clicking and low brake performance when trying to slow down, especially with the steering wheel turned.

 

[BlueMissile]

I slipped a stealth edit in there - based on the fact that it was saying that it wouldn't go into hold mode I'm thinking the iBoost died and she didn't realize how hard you have to push to get the car to slow down.

The clicking could be the ABS going off, that generally sounds like solenoids switching on and off. I will say that the ABS and iBoost work together to do hold mode. I have heard of other people having issues with wheel speed sensors getting installed improperly and worn through by suspension or the tires. In that case the ABS can exhibit all sorts of wierdness (like turning on when it doesn't need to.) But again the car should still slow down, just not as much as expected.

Coincidentally my wife's Ford Escape Hybrid just had a problem occur again with a bad wheel speed sensor for about the 3rd time - she also is getting clicking and low brake performance when trying to slow down, especially with the steering wheel turned.

It is definitely interesting. She grew up driving a huge truck with older brakes. So I'm going to still stick with that she had it to the floor trying to stop the car. Especially after the first time it happened.

If this were to be the problem, is it the fault of Tesla? The parts specific manufacture?

Tesla now let me know earlier they are still reviewing everything on their end and they will follow up with me again on Monday. Who knows how long this will take.

One of the service managers did mention to me when I was picking up my loaner that they wouldn't release the car back to me without them being able to diagnose the problem if the brakes did fail in anyway and resolve it? What happens then? I'm out the car?

 

[Gninoked]

It is definitely interesting. She grew up driving a huge truck with older brakes. So I'm going to still stick with that she had it to the floor trying to stop the car. Especially after the first time it happened.

If this were to be the problem, is it the fault of Tesla? The parts specific manufacture?

Tesla now let me know earlier they are still reviewing everything on their end and they will follow up with me again on Monday. Who knows how long this will take.

One of the service managers did mention to me when I was picking up my loaner that they wouldn't release the car back to me without them being able to diagnose the problem if the brakes did fail in anyway and resolve it? What happens then? I'm out the car?

If there's not some physical damage that could be done by a person or road debris it's definitely a warranty issue. They don't want to give you back a car without being able to explain what failed, why and a complete repair with any sort of brake issue.

I haven't heard of any ABS failures, the car uses a fairly standard Bosch unit.
I know they have already revised the iBoost unit, and I've heard of a failure or two, but that system is not Tesla specific and used on some other cars. No one as far as I can tell has determined why they changed the part, could simply be a vendor revision.
The brake capacity is generally fairly low (due mainly to the low friction pads they selected and identical to the non-plaid car) but I haven't heard of any failures in the other hydraulic components and they all seem to be fairly high quality.
We had a different failure in a extremely rare condition on our Plaid and Bosch/Tesla were very interested and able to resolve it for everyone everywhere.

 

[BlueMissile]

If there's not some physical damage that could be done by a person or road debris it's definitely a warranty issue. They don't want to give you back a car without being able to explain what failed, why and a complete repair with any sort of brake issue.

I haven't heard of any ABS failures, the car uses a fairly standard Bosch unit.
I know they have already revised the iBoost unit, and I've heard of a failure or two, but that system is not Tesla specific and used on some other cars. No one as far as I can tell has determined why they changed the part, could simply be a vendor revision.
The brake capacity is generally fairly low (due mainly to the low friction pads they selected and identical to the non-plaid car) but I haven't heard of any failures in the other hydraulic components and they all seem to be fairly high quality.
We had a different failure in a extremely rare condition on our Plaid and Bosch/Tesla were very interested and able to resolve it for everyone everywhere.

The car was immaculate besides any small rock chips on my PPF and the door handles still needing alignment for the "due bill" items.

I am hoping they can resolve this fairly quickly while fixing whatever the problem is so that it doesn't occur to anyone else or at all for that matter. However, going from three newer Teslas (19-21) to '15 loaner isn't a fun adventure.

 

[Gninoked]

The car was immaculate besides any small rock chips on my PPF and the door handles still needing alignment for the "due bill" items.

I am hoping they can resolve this fairly quickly while fixing whatever the problem is so that it doesn't occur to anyone else or at all for that matter. However, going from three newer Teslas (19-21) to '15 loaner isn't a fun adventure.

I hear that - hope they figure it out quick. I suspect they might.