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

[brico84]

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?

Not sure what you mean by full ABS stops?

I haven't had a scenario where I would need ABS to engage like stopping short in the rain or anything. Braking has felt completely normal since "the incident". We had a week of storming here recently but don't think the ABS engaged at any time. I usually drive in a manner that lets regen do most of the braking. I don't often need to brake hard.

 

[brico84]

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.

Not sure what you are implying. I think a normal response to this kind of scenario is take it to Tesla which I have been trying to do. I had a hard time getting an appointment, and when I did, as it approached they gave me this BS estimate. I was then going out of the country for 2 weeks. When I got back I contacted the manager to try and work it out. I got no response and after a week followed up with him yesterday to which he finally responded. Had he responded positively I probably wouldn't have posted here. My goal is to get the issue resolved without wasting a ton of money. I guess I am not as active a member of the community. Is that what you are implying?

 

[jjrandorin]

Not sure what you mean by full ABS stops?

Im not @gsmith123 but that term "full ABS stops" I would normally take to mean driving and then (after you find someplace safe to test this) stepping on the brakes hard enough to activate ABS, which would normally be called "stomping on the brakes". ABS has a specific sensation in the brake pedal that if you are familiar with it is fairly unmistakable.

@gsmith123 is likely asking you that question to see if you have determined if your brakes are still working properly if you "call for maximum braking by stomping on the pedal hard enough to activate ABS".

 

[brico84]

Im not @gsmith123 but that term "full ABS stops" I would normally take to mean driving and then (after you find someplace safe to test this) stepping on the brakes hard enough to activate ABS, which would normally be called "stomping on the brakes". ABS has a specific sensation in the brake pedal that if you are familiar with it is fairly unmistakable.

@gsmith123 is likely asking you that question to see if you have determined if your brakes are still working properly if you "call for maximum braking by stomping on the pedal hard enough to activate ABS".

Gotcha. No I haven't tried that. I mean I was in bumper to bumper traffic when this happened crawling along at 5 - 10mph. I don't think ABS would need to be engaged to stop the car. I even checked the drive on Teslamate and I was definitely only going around that slow speed. So I am not sure ABS would be a factor. I brakes regular and the car kept moving. I only pressed harder and all the way down because of course the car did not brake so I was trying to do all I could to stop. And it still didn't engage the brakes when I did so for a good few seconds. At the last second it stopped. Not like screeching or anything, just like it wasn't working at all for 5 - 7 seconds and then decided to work at the last second (in a regular manner).

 

[gsmith123]

@jjrandorin yes exactly.

I'm not saying ABS typically would be needed in stop and go traffic. But when you press the brake hard, like you describe, one of two things always happen (when the brakes are working correctly): ABS noticeably engages, or you stop.

I suggested doing a few "stomp the brakes" stops mostly as a troubleshooting measure. If I was suspicious something was off with the brakes I'd (safely!) find an open space and try stomping the brakes from 10-20 mph, trying some more gradual braking, etc. Various scenarios to try to see if any of them feel "off". I'd look for things like: poor deceleration, mushy pedal feel, sinking pedal feel, ABS not engaging, etc. Anything abnormal.

On the off chance something feels off, well, then you've got another data point to help diagnose this (and a way for a mechanic to reproduce it!).

 

[brico84]

Thanks I'll see if I can find a spot to try that. I live in the city so it will be difficult but I'll try and figure something out. Appreciate the suggestion

 

[ucmndd]

I think a normal response to this kind of scenario is take it to Tesla which I have been trying to do. I had a hard time getting an appointment, and when I did, as it approached they gave me this BS estimate.

I think your expectations here are simply unrealistic. It appears you want Tesla to diagnose and work on your 7 year old car for free or at minimum significantly less than their normal shop rate. That’s not going to happen. An estimate of two hours to diagnose an issue like this is perfectly within the realm of reason.

Since you’re adamant that there’s no fathomable “user error” explanation and don’t wish to entertain any possibilities there, your choices are really pretty simple:

Keep driving the car until it happens again and you maybe crash into something. Or maybe it never happens again. In any case, the choice here is “accept the risk.”

Take it to Tesla, let them diagnose the car, and pay their fee. They’re extremely unlikely to negotiate with you.

Find a third party willing to take a look and pay them instead.


There’s no magic to this. If you have a failing master cylinder / brake booster then you probably want to get that fixed. This is how owning an out of warranty car goes.

 

[zoomer0056]

Not sure what you are implying.

Sorry, no need to read between the lines. Take what I say directly, without implications.

 

[KalJoMoS]

I haven't had a scenario where I would need ABS to engage like stopping short in the rain or anything. Braking has felt completely normal since "the incident". We had a week of storming here recently but don't think the ABS engaged at any time. I usually drive in a manner that lets regen do most of the braking. I don't often need to brake hard.

You have just experienced a seized brake caliper phenomenon. In all of your answers you have indicated that you have never done any brake service on your car. I do not know how does the humidity affects in Florida but I bet it’s far from desert dry conditions. I would use that asked amount in ordinary brake shop to change out the front pads as they are the main factor to get your car to stop. You did described that since the situation you have not experienced that again, this proves that by the braking situation you had, the seizure is not cleared. I would not hesitate to change also the front discs as well, this would be a service that you will not regret. I just did this same change last month and you don’t know how much have the braking now changed! I now alway have a check on my mirror’s as not wanting to get rear ended, the difference is clear as a nigth-and-day effect. If you find the garage to get the change then ask them to lubricate the rear pad’s as well, they would not need to be changed. Have to find that post of the servicing my brakes.
If you take your car to Tesla then they will not work on it before they have upgraded it to recent SW as their new ToolBox3 is not working with your current version (don’t ask me how I know!). If able I would avoid them. And I’m sure you have no data point on the logs as this situation was as ordinary as your every other driving have been.
p.s. That ABS does not work in 5-10mph speed traffic.

edit: found my post about that service…

 

[mykohsu]

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.)

Is that true?

I do have edr logs that posssibly indicates my vehicle speed continued up when accelerator was not pressed and service brake was on. The service brake logs aren't granular enough to be sure, but does indicate for the last 0.5s brake was on whole vehicle gained speed until 0.3s before.

Acceleration data indicates negative g at 0.5s. I think this just means the brake took 0.2s or so before forward acceleration finally became negative because the cruise control was accelerating the vehicle right before.

Personally I think 0.2s is way too long to counter the acceleration, but maybe the same was happening in OPs situation.

 

[cbdream99]

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...

Out of warranty Tesla is never cheap to own. From my experience, Tesla app or at least initially will give stock problems/answers and quotes. Once it got closer to the appointment date, they may look at it more. They have before quoted me fees for suspension checks and charging system checks but didn't charge me at the end, however YMMV and it very much depends on how much time they actually spent on it.

You don't have much choice in terms of service ... TSC, EG. DIY. In the old days, there are Midas, Meineke that do brake check for free but often will give you a quote by looking at your face, if you can find a honest one then you are in luck, most of them however won't touch a Tesla, though it is not much different from other cars in reality.

IMHO, you should have it check out, just for the safety of yourself and others, I have encountered multiple times that stupid teenagers running in front of traveling cars including mine to brake check the drivers thinking it was fun ... In fact, I got dinged for hard braking for that just few weeks ago

 

[brico84]

You have just experienced a seized brake caliper phenomenon. In all of your answers you have indicated that you have never done any brake service on your car. I do not know how does the humidity affects in Florida but I bet it’s far from desert dry conditions. I would use that asked amount in ordinary brake shop to change out the front pads as they are the main factor to get your car to stop. You did described that since the situation you have not experienced that again, this proves that by the braking situation you had, the seizure is not cleared. I would not hesitate to change also the front discs as well, this would be a service that you will not regret. I just did this same change last month and you don’t know how much have the braking now changed! I now alway have a check on my mirror’s as not wanting to get rear ended, the difference is clear as a nigth-and-day effect. If you find the garage to get the change then ask them to lubricate the rear pad’s as well, they would not need to be changed. Have to find that post of the servicing my brakes.
If you take your car to Tesla then they will not work on it before they have upgraded it to recent SW as their new ToolBox3 is not working with your current version (don’t ask me how I know!). If able I would avoid them. And I’m sure you have no data point on the logs as this situation was as ordinary as your every other driving have been.
p.s. That ABS does not work in 5-10mph speed traffic.

edit: found my post about that service…

Humidity here is almost always 99%.

Thanks for this info.

 

[brico84]

Out of warranty Tesla is never cheap to own. From my experience, Tesla app or at least initially will give stock problems/answers and quotes. Once it got closer to the appointment date, they may look at it more. They have before quoted me fees for suspension checks and charging system checks but didn't charge me at the end, however YMMV and it very much depends on how much time they actually spent on it.

You don't have much choice in terms of service ... TSC, EG. DIY. In the old days, there are Midas, Meineke that do brake check for free but often will give you a quote by looking at your face, if you can find a honest one then you are in luck, most of them however won't touch a Tesla, though it is not much different from other cars in reality.

IMHO, you should have it check out, just for the safety of yourself and others, I have encountered multiple times that stupid teenagers running in front of traveling cars including mine to brake check the drivers thinking it was fun ... In fact, I got dinged for hard braking for that just few weeks ago

Thanks I'm gonna do some research and see if I can find a decent regular shop that will do an inspection for free and has experience with Teslas. I'm also gonna reach out to EG because I have a few small things I haven't taken it in for as they weren't major but if I'm bringing it in would get fixed (eyebrow burnout, driver window screeching on opening, rear ac vent clip broken).

 

[KArnold]

I'm gonna do some research and see if I can find a decent regular shop that will do an inspection for free and has experience with Teslas.

EG is always a good option but any decent shop can troubleshoot hydraulic brakes - there is nothing special about Tesla brakes that can cause this. Many backyard mechanics can as well. I agree it has to be hardware, no doubt - leaking hydraulics being my first guess but also the basics - rotors, calipers, pads. Again any shop can deal with those. They are actually pretty easy to diagnose and repair, relatively speaking. No need to pay Tesla shop rates. I'm sure many would also do a free eval. If you know how to check your brake fluid level, I'd start there - if low (or old) you have a major clue. Or perhaps moisture/air has entered the system. If nothing definitive is found I would replace/bleed the hydraulic fluid at minimum which is also good regular preventative maintenance.

Or if you have a jack, put the car in neutral, chock the wheels, lift one corner at a time off the ground, manually spin the wheel, and apply brakes. They should stop immediately. With the brake applied try to manually turn the wheel and it should not budge.

Did you say how many miles? Ever have brakes serviced?

It's not software. No way.

Personally I would not drive a car with a potential fatal flaw more than 10 feet, not even to a shop.

 

[vcor]

Looking at all the prior responses, I'm not sure it was clear to you that the brakes will work even if the CPU is down, and even if the 12v power is dead. Looking at the logs is pointless. While software can activate the brakes, there is no way for it to stop the brakes from functioning if you are pressing on the pedal. You could lose the power assist if there was no electrical power, but the brakes still work. So pressing hard on the brake and having it not work indicates to me a mechanical issue.

Others have chimed in with some reasonable ideas, but the brake system really should be physically looked at, and perhaps some proactive work done, even if the problem is not duplicated. Perhaps Tesla's diagnostic might even be cheaper if they are looking for a hardware brake problem, and not wasting time looking at the logs as you were trying to force them to do.

 

[Gumball]

So you are worried about your brakes failing on a seven year old car, had never any brake work done, and now want Tesla to diagnose the issue for free. I would say dream on, but that would be rude.
If you really are that worried about your car having failing brakes, pay for a diagnose. Next time you could kill someone or yourself, if the brakes are really failing.

 

[Jbuntz]

I had a similar situation in my Nissan Leaf when the 12v battery was low and so the brake booster was not working. It felt as though the brake was not working but in fact if you used both feet full force it would stop.