Car continuing to move forward even with brake pressed down all the way

[brico84]

So I am sure I am going to get all sorts of people replying telling me how this is impossible, and the only way this happened was if I was pressing the accelerator. I urge you to keep those replies to yourself as that is not what happened. Here are the details...

2017 S75 RWD. Running Software version 2021.44.6 (did not want to upgrade to v11 interface and lose 90 mph autopilot, so I haven't upgraded). I am looking to find out if anyone else has experienced something similar, and how to navigate this with Tesla. Nothing like this has ever happened to me before in the many ears of driving the car, nor sense. Here is what happened.

About a month ago, in bumper to bumper traffic, stop and go, my car was approaching the car in front of me, about 10 - 15 feet away, and I hit the brake. Except the car didn't slow down... at all. As if the brake wasn't pressed. I was only going about 5 - 10 mph. I pressed harder and harder... Basically pressing the brake down to the floor like you do when you put it in hold mode. There was no chance my foot was on the accelerator, if it was, I would have slammed in to the car in front of me, and would have been picking up speed. Instead the car ignored my brake pressing until it was about 2 - 3 feet from the car in front of me and then finally stopped. There was no screeching, or hard stop or anything like that, because as I mentioned I was only going about 5 - 10 mph. I was completely freaked out, but glad that I didn't get in an accident. I immediately submitted a bug report through the steering wheel option. At no point did my foot move from one pedal to the other, so again, no chance it was the accelerator. The whole time I was pressing on a single pedal... the brake.

I did have autopilot engaged on and off through the bumper to bumper traffic. I don't recall exactly if it was on prior to me pressing the brake for this instance, but even if it was, it would have disengaged right away with the brake pedal press (and if I was pressing the accelerator, it would have slammed in to the car in front of me)

I set a service appointment with Tesla and asked them to review the logs. I got an estimate to look at the logs for 2 hours, at $610 ($305 per hour). Absolutely outrageous. I followed up with the service manager who I have worked with before advising him that this is kind of ridiculous. Asking why can't they look at the logs remotely. In my experience with Tesla, likely if I pay this money, they are going to come back and say they couldn't find anything wrong.

I got a response from the manager as follows....


"I truly understand your concerns about the diagnostic fees being applied but for us to consume a technician's time on reviewing vehicle logs we are obligated to charge for these services.

Our Virtual teams offer an overview of the vehicle at no cost which I see was already done but we are recommending the vehicle come into service in order to have an actual technician root cause your concern.

I see you’re set to come into service on the XXXX of this month please let us know if you would like for us to further investigate this issue and you can do so by approving the estimate provided."


Now, if I had pressed the accelerator, not only would I have crashed in to the car in front of me, but I'm pretty sure they would have seen that in the remote diagnostics and told me as much.

I am trying to navigate how to proceed here, because I don't have $610 to waste. If there is a valid part failure (though for the life of me I can't think of a part that would fail that would cause something so crazy as this), then I am fine paying for a fix. But I am not ok wasting $610 for them to look at something that should never happen, and to have them tell me that nothing is wrong with the car.

I thought about reporting this to NHTSA, or responding advising as such, but I am not sure that will get me anymore. If i was a twitter celebrity, I would just post this and tag Elon and I'm sure I would get a quick response to get this handled, but sadly, I am not. You would think Tesla would WANT to investigate stuff like this.

Anyone have any good suggestions on how to get Tesla to look at this without charging me an arm and a leg?

 

[ucmndd]

Questions that come to mind reading your description:

Was it raining? What you describe sounds a lot like an ABS engagement.
Is it possible the car in front of you was rolling backwards instead of you rolling forward? Very easy to get disoriented like that in heavy traffic with things moving all around you.

In any case, we're talking about 6+ year old car. I don't think Tesla is being unreasonable in terms of not wanting to work for free in this case.

 

[brico84]

Not raining. No ABS engaged. Car was not rolling back to me.

 

[bay74]

Car of mine does similar because it has a leaky master cylinder: you press and get almost no response, pump again and get some response, another pump and you've got brakes. For a few seconds, then you feel the pedal moving down again as it leaks. But it's consistent behaviour in that it's always like this. Weird if a Tesla did this 'cause they're still so new (my vehicle with the dodgy master cylinder is 54 years old) but I guess there could always be a manufacturing defect.

Wasn't explicit from your post but I assume your incident was a once-off so my experience is probably not helpful to you - though it sounds to me like a brake hardware issue in any case.

Good luck. Cheers.

 

[MP3Mike]

About a month ago, in bumper to bumper traffic, stop and go, my car was approaching the car in front of me, about 10 - 15 feet away, and I hit the brake. Except the car didn't slow down... at all. As if the brake wasn't pressed. I was only going about 5 - 10 mph. I pressed harder and harder... Basically pressing the brake down to the floor like you do when you put it in hold mode. There was no chance my foot was on the accelerator, if it was, I would have slammed in to the car in front of me, and would have been picking up speed. Instead the car ignored my brake pressing until it was about 2 - 3 feet from the car in front of me and then finally stopped. There was no screeching, or hard stop or anything like that, because as I mentioned I was only going about 5 - 10 mph.

Tesla has a traditional braking system, short of a physical part failure, pressing the brake pedal applies the brakes. There is nothing in software that can prevent, or delay, that, short of ABS activation. (Which you say didn't happen.)

 

[Tam]

Not raining. No ABS engaged. Car was not rolling back to me.

When braking didn't slow down the car, did you take your foot off the pedal the tried again? Or it was one continuous press until the car finally stopped?

I am trying to figure out whether pumping the brake repeatedly a good idea.

 

[brico84]

When braking didn't slow down the car, did you take your foot off the pedal the tried again? Or it was one continuous press until the car finally stopped?

I am trying to figure out whether pumping the brake repeatedly a good idea.

I didn't take my foot off, just pressed harder until it was all the way down...still nothing for a second or two... prepared for an accident, foot still on the brake all the way down, and then all of a sudden it stopped.

 

[brico84]

Car of mine does similar because it has a leaky master cylinder: you press and get almost no response, pump again and get some response, another pump and you've got brakes. For a few seconds, then you feel the pedal moving down again as it leaks. But it's consistent behaviour in that it's always like this. Weird if a Tesla did this 'cause they're still so new (my vehicle with the dodgy master cylinder is 54 years old) but I guess there could always be a manufacturing defect.

Wasn't explicit from your post but I assume your incident was a once-off so my experience is probably not helpful to you - though it sounds to me like a brake hardware issue in any case.

Good luck. Cheers.

Was a once off, did not happen before, and has not happened since.

 

[jjrandorin]

So I am sure I am going to get all sorts of people replying telling me how this is impossible, and the only way this happened was if I was pressing the accelerator.

My first thought reading what you wrote is not "only way that could have happened is if they pressed the accelerator" (because the brake pedal overrides the accelerator).

My first thought reading what you wrote is that you had something failing in your braking system, either a leak in your brake lines or something else in the brake line that needed to be looked at. I certainly didnt think it had anything to do with autopilot, fsd etc, just an issue with your brakes that you probably should get looked at.

The second thing I thought of was, " I wonder if the OP is wasting their time contacting Tesla since tesla will probably say the car should be updated to a later firmware version, or worse, simply do that if they take the car in to look at it, and it does not appear the OP wants that".

 

[brico84]

Yes, I am also worried about them updating my software as an excuse to fix the issue, but you would have to think that...regardless of the software version... the brake should brake. But yes, I am fairly certain they are going to force update me even though they haven't in the past at my request.

I am ok with being updated if it is needed to fix this issue because obviously I never want this to happen again. But I am concerned that is going to be there only "fix", and I am not convinced updating the software will fix whatever is wrong.

So I am worried I am going to spend $610 to have them say "nothing is wrong but the software needed to be updated" (if nothing else then because of the recent "recall"), and end up with updated software I don't like, and the issue might still happen again.

 

[jjrandorin]

So I am worried I am going to spend $610 to have them say "nothing is wrong but the software needed to be updated" (if nothing else then because of the recent "recall"), and end up with updated software I don't like, and the issue might still happen again.

if I was in your shoes, that would be what I was worried about too, since you have a problem, and are on very old software. Your car isnt under warranty, but Tesla even gates warranty service to "keeping the software up to date" in their warranty paperwork, so they "can" force people to upgrade for warranty service.

Not applicable to you of course, but I could see them starting there and saying "try it now" or something.

Have you had your braking system fully inspected? If it were me I would start there, since functioning brakes override any acceleration input, and "brakes to the floor" does not sound like functioning brakes.

 

[cbdream99]

If I were you, I will take it to the SC to have them inspect it. I have the same model and year, never seen this before. Also, I assume you have stiooed driving the car..

 

[brico84]

if I was in your shoes, that would be what I was worried about too, since you have a problem, and are on very old software. Your car isnt under warranty, but Tesla even gates warranty service to "keeping the software up to date" in their warranty paperwork, so they "can" force people to upgrade for warranty service.

Not applicable to you of course, but I could see them starting there and saying "try it now" or something.

Have you had your braking system fully inspected? If it were me I would start there, since functioning brakes override any acceleration input, and "brakes to the floor" does not sound like functioning brakes.

I could try taking it to electric garage, they would probably look at it for me without forcing an update, but short of that, I am not sure where else i could take it to have the brakes look at specifically in that manner. Plus having access to the logs is also useful I think for overall diagnosis.

I have X-Care warranty coverage, so any real issue will be covered and reimbursed, but I need to have a claim created first, and have it approved by them before the work is done or they wont cover it after the fact.

 

[brico84]

If I were you, I will take it to the SC to have them inspect it. I have the same model and year, never seen this before. Also, I assume you have stiooed driving the car..

You assume wrong, I have to get around so I have been driving it since the issue (about 5 weeks now) and nothing else has come up like it, though obviously it only needs to happen once to be a problem. I was pretty freaked out at first, but everything seems normal, and I can't get to work or do anything else without a car, so I have mostly not worried about it in that sense, but obviously I am trying to get this fully looked at and resolved.

And yes, I recognize that it is probably stupid of me to be driving it, and the safe thing to do would be to not drive it...

 

[zoomer0056]

From your post and the responses it does not seem like a software issue (I can only speculate). Just have your brake system checked out. Like one poster said, in the ICE ages with no brakes, it's instinctual to pump 'em.

Edit: I see more posts. I am surprised it's been more than a month and your just now coming to us with this because its not resolved yet. For safety, I would've taken it in right away and started with a brake system inspection.

 

[chronoreverse]

If this happened like you said, there's most likely a physical fault in the traditional braking system (possibly including fluids) that needs to be looked into.

 

[fholbert]

Questions that come to mind reading your description:

Was it raining? What you describe sounds a lot like an ABS engagement.
Is it possible the car in front of you was rolling backwards instead of you rolling forward? Very easy to get disoriented like that in heavy traffic with things moving all around you.

In any case, we're talking about 6+ year old car. I don't think Tesla is being unreasonable in terms of not wanting to work for free in this case.

I'm with @ucmndd . Someone in front of you, or beside you was rolling. It was an optical illusion.

Or you've been smoking "medical marijuana".

 

[brico84]

I'm with @ucmndd . Someone in front of you, or beside you was rolling. It was an optical illusion.

Or you've been smoking "medical marijuana".

I'm pretty sure I saved the dashcam footage, I'll have to check, but no.... that is not what happened. Nobody was rolling, nor smoking. Just me not braking.

 

[fholbert]

There is only one other answer.

You were caught in a tractor beam.

 

[gsmith123]

If this happened like you said, there's most likely a physical fault in the traditional braking system (possibly including fluids) that needs to be looked into.

If we take the report as completely true, then we can go further and say there must be a fault with the hydraulic brakes. Working normally the mechanical brakes alone in a car should be able to override the motors (regardless of how software may be inappropriately requesting motor torque).

And ABS didn't engage per the report so that rules out some weird oil spill or slick surface as the sole cause.

Post incident have you tried any full ABS stops from 20-30 mph? Do they feel normal?