Total braking system failure?

[SSSimon]

Total Brake Failure would almost always mean that the brake pedal was pressed all the way to the floor without actually activating any brake force. There are major components which must fail for this to happen, e.g. front & rear hydraulic brake hoses ruptured as front and rear work on separated hydraulic circuits. Can OP please update the thread title to describe the actual issue, e.g. Brake Pedal Seems Locked in the Up Postion?

 

[Sophias_dad]

Side note: dual brake systems are diagonally connected(and have been for decades, I believe), such that one front and the opposite rear wheel get braking from the same circuit.

This was presumably done because if you lose only the front brake circuit, the rears are really dismal in stopping the car and really great at throwing it out of control.

Its entirely possible to lose both circuits at once, usually because one circuit fails and the operator doesn't notice(or ignores) the light, or the light circuit/switch fails, and then eventually the other brake circuit fails at some random point in the future.

Another somewhat smaller likelihood of dual-failure is if something(like the driveshaft) fails and damages the brake lines that feed the rear brakes(talking to you, Jeep!), or if said lines are quite rusty and someone presses very hard on the brakes.

 

[duncan]

It was probably a failure of the brake booster
And non boosted brakes are HEAVY
The problem is not your leg strength - its what you are used to
Even a fairly weak person will still be able to get full brakes - but they will have to push HARD

Way back in the 80's I had a lovely Lancia Spyder - everything manual
I had to take a company car for a three day trip - I think it was a Ford Escort - power brakes, power steering
When I got back and jumped into my Lancia everything was stuck
the clutch would not move, the steering was solid the gear change was stuck
It took a couple of days before it all felt normal again

The control loads we used to think of as "normal" feel enormous after driving todays cars

 

[Bill25cycle]

As others have pointed out, you really have to use all of your leg muscle and a lot of your back strength to manually brake.

My first car was a 1964 Buick Skylark with manual brakes. My right leg was huge by the time I finally parked that car for the last time.

I bought many old junker cars that always had manual brakes, and manual steering. Maybe slightly built women absolutely needed them but it was second nature for any reasonably fit male.

The issue he is talking about here seems to have a big safety issue. During any kind of power assist failure, the assistance is not supposed to be so much of a hindrance to normal operation of the car - although manufacturers get away with the disclaimer that

"Loss of power assist may require more force than would be required if no assist was normally provided" - in other words, a failure in the power assist system in either brakes or steering requires MORE effort than manual steering or braking requires.....

But here, if the commenter is accurately portraying the situation, and I have no real reason to doubt him, the power-assist failure BLOCKED the manual application of the brakes.....

Very bad if that is the case. The 'assist' should be exactly that - not a 'replacement' that you totally lose if there is trouble.

 

[alsetym]

The physical braking system in my Model 3 completely failed this morning.
I didn't realize it until I got on the freeway ramp and almost hit the car in front of me.
Luckily, the regen braking was enough to slow the car down.

The brake pedal felt like it was in a locked position at the top of its range. Could not depress the pedal at all.

This was an absolute critical safety failure.

The car was acting strange from the first moment this morning.
1. erratic window roll down behavior when I opened the front door
2. dark/blank screen upon entry
3. warning message: vehicle hold feature unavailable
4. warning message: 12 v battery must be replace soon

After I rebooted the car, I drove off to working thinking it was nothing.
After realizing the brake failure, I got off the next freeway and exit and drove it back home safely.
With the road side assistance tech on the phone, I tried rebooting the car with no luck.
Then, tried powering the car off via the lcd screen and waiting a couple of minutes seems to solve the issue this time.

The car is now with the Tesla service center.

How could this happen? This was extremely dangerous and I feel very fortunate.
I could have easily found out the hard way at 70+ mph.

Hope this never happens again to me or anybody else, ever.

Ah jeez. Can we please rename this thread to 'power brake booster stopped working' OR 'why didn't my parents ever pull the vacuum source off the brake booster while teaching me to drive to show me what it feels like and how to brake with no boost'. Could also change it to 'my car warned me the 12v battery was failing, drove any way, then 12v systems stopped working and i'm blaming -insert political affiliation here '

I'd hate to 8magine what will happen to you when your steering boost fails.

 

[Stratman]

I have an electronics engineering background and I think its highly likely given all of the random errors and happenings the Op experienced are all related to the low voltage from the12 Volt battery (and the systems software response to this low voltage) . Given the fairly common failure of the 12 volt battery in the M3 (most of the first shipments of cars delivered to Australia had all of their 12 volt batteries replaced prior to delivery... mine included) Depending on each module in the car and its level of complexity , its ability to correctly function with lower voltage and also the systems software responses to low voltage and errors could lead to something like this.

From my working experience the FIRST two steps for a technician in repairing anything electronic is 1. Observation 2. Check system voltages. So many strange fault / errors / issues can be related to low system voltages. 12 volt systems are notorious because of wiring looms and connecters which can easily drop 50-500mV if not securely seated or dirty/ old etc. The terminals on the 12 volt battery itself could drop voltage.

I have no doubt Tesla will treat this issue with high importance. Given the common place issues with the 12 Volt battery we should have an option to display the battery voltage and a graph trending 12 volt performance over time- without having to buy a 3rd party dongle.

Unless the 12 Volt batteries are dying suddenly, the cars software should be able to advise us when the 12V battery is degrading and give a replacement an alert before it fails.

It is possible there was also a mechanical fault preventing the brake pedal being pushed, but in this case I think this is unlikely given the other errors that had just occurred. Probably the Op just didn't push hard enough for mechanical application of the brakes.
This would not be unusual as the force required is quite high.

 

[RayDiPaola]

Cars with no power brakes and drums all around are much easier to stop than cars with disk brakes where the power boost system fails. It takes an enormous effort and can be very scary the first time it happens. If you had to drive such a car for a bit of time while scraping up the nickels to get it fixed you will never forget the feeling...

 

[alsetym]

was it the explicit battery warning message that tipped you off?

Sounds like a dying->dead 12V battery problem. What year is the car? A lot of 2018s with dying batteries lately. You probably shouldn’t have drove off after the first warning.

 

[acasano]

The brakes are a mechanical system with electronic power. Like GoSharks said the power boost goes out you will have to "lean in" to get them to work. Just think a few decades ago most brakes didn't have power so it was a leg "workout" just driving.

I have a 2018 Model 3 and the 12v battery was replaced. I had many of the symptoms described as well. Owners, as others in this thread have stated, must be aware of the risk of driving with the 12v warning sign on display. Besides having the brakes feel odd the driver side window had to be adjusted by the Tesla Tech who replaced the battery.

 

[DDotJ]

Just wanted to add my .02 to give OP the benefit of the doubt. If my car had several errors on the display I would personally call Tesla before taking it out on a drive but I can also see why some people may not.

1. erratic window roll down behavior when I opened the front door

This is a bit odd, but I probably wouldn't have given it too much thought. I may have reset the window module and went on my merry way.

2. dark/blank screen upon entry

This I find is not uncommon for me, especially after not being driven for a while sometimes the screen will be dark upon entry and takes up to 30 seconds to "boot up".

3. warning message: vehicle hold feature unavailable

IMHO this warning is the one that would give me pause. I probably would have rebooted the car via the service menu to clear the error. I have seen this error briefly flash on screen before, IIRC it went away with a reboot.

4. warning message: 12 v battery must be replace soon

I had this error message on my Model X a couple months ago. I called Tesla Roadside/Tesla Service and they told me that with this error it was perfectly safe to drive. The person I spoke with over the phone said it just means that I should take it to service ASAP as in their experience it's about a 1 week warning before the 12v battery kicks the bucket. But they emphasized it was okay to drive.

Glad OP is safe though, definitely let us know what Tesla Service says. I will definitely be more cautious regarding these errors.
I'm one of those people that have never driven a car without power steering or braking assist so I've learned a great deal on how to deal with a brake booster failure thanks to this thread. Hopefully it never comes to that

 

[Backpacker42]

The physical braking system in my Model 3 completely failed this morning.
I didn't realize it until I got on the freeway ramp and almost hit the car in front of me.
Luckily, the regen braking was enough to slow the car down.

The brake pedal felt like it was in a locked position at the top of its range. Could not depress the pedal at all.

That sounds like a booster failure. If the failure is due to low 12 Vdc, I agree it is a poor design. I can't get into the car without 12 V, and if I have no cell service that is a real issue, and doubly so if the emergency brake is also dependent on 12 Vdc. At the very least the car should warn me weeks in advance that I have a potential 12 V battery failure.

As an aside, I no longer let people drive my 69 wagon because everyone these days are so used to power brakes. Even after being warned, their reaction at the first stop sign is always "MY GOD! Your brakes can't be working properly!!". You can imagine how hard it was for me to adapt to power brakes when I'm so used to slamming the pedal hard with both feet for emergency stops.

 

[Backpacker42]

That sounds like a booster failure. If the failure is due to low 12 Vdc, I agree it is a poor design. I can't get into the car without 12 V, and if I have no cell service that is a real issue, and doubly so if the emergency brake is also dependent on 12 Vdc. At the very least the car should warn me weeks in advance that I have a potential 12 V battery failure.

As an aside, I no longer let people drive my 69 wagon because everyone these days are so used to power brakes. Even after being warned, their reaction at the first stop sign is always "MY GOD! Your brakes can't be working properly!!". You can imagine how hard it was for me to adapt to power brakes when I'm so used to slamming the pedal hard with both feet for emergency stops.

 

[M109Rider]

Hey do you even get a warning message for this?

View attachment 596289

loss of cabin pressure?

I was waiting for you to dive into this incident. You’ve made several references already within this braking thread. I’m surprised you waited this long, you must have been jumping up and down for the opportunity.
I’m wondering how many times you’ll use this one in your on going effort to get back at Tesla.

 

[carletonm]

This sounds like the MCAS problem with the Boeing 737 MAX!

 

[erb2000]

OP, that's terrifying. One thing I learned after reading your post is that there is a way to trigger the emergency brake.

Hopefully whatever failed in your car does not also take out the ebrake. If so, the lack of redundancy is poor design indeed!
View attachment 595669

I did that once by accident trying to wash my windshield...

 

[Sam1]

The fact that people are actually disagreeing with this, just reinforces my point. It would be like learning how to skydive and not ever inquiring on how to pop the reserve chute when you have an issue and loose the main. good grief

 

[iwannam3]

View attachment 596341

The fact that people are actually disagreeing with this, just reinforces my point. It would be like learning how to skydive and not ever inquiring on how to pop the reserve chute when you have an issue and loose the main. good grief

The button has a P on it, and indicates P on the display, not an E for emergency. Would you slam an auto transmission in to park at 60 mph if your brakes were funny?

 

[Mash]

The button has a P on it, and indicates P on the display, not an E for emergency. Would you slam an auto transmission in to park at 60 mph if your brakes were funny?

No, but I would spend 20 minutes of my time reading the manual on a car that I just bought...

 

[CertLive]

What this seems to suggest until proven otherwise is that 12v warning can possibly have more repercussions if it fails than simply powering general electronics or getting the car going.

The safety question here is when there is a loss of 12v power while driving do you lose the brake booster and can it lock the brakes out? Which feels a little ironic sitting on a huge battery.

For the babies doing rattle shaking ill translate.... Go to press brakes they didn't work, not the OP;s fault in any way. He is asking questions as anyone would.

 

[Pilot1226]

No, but I would spend 20 minutes of my time reading the manual on a car that I just bought...

+1, though I do recognize that I am probably among the minority of people that have read manuals cover to cover. There were 4 manuals with my Subaru: owner’s manual, warranty and maintenance manual, eyesight manual, and Starlink (infotainment) manual. Each one was pretty heavy but had useful info that seems to be overlooked due to thread postings.