Parking Brake unexpected Release (MT)

[Kroberter]

Anyone have the parking brake release randomly on a manual transmission?
I was chillin after starting it, selecting some music and I rolled out of the parking space. Never hit the clutch or brake besides the initial start. The parking brake released a solid 20-30 seconds after I was sitting there.
I initially thought it released with a clutch friction sort of logic like the hill hold feature but what happened today makes me think it’s defective.
I’ve also had the brake release right after I set it before I was able to hit the engine stop.

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[Davidr3]

That's pretty scary. I'd be paying a visit to the dealer asap

 

[Adrenaldestruction]

I experienced something similar last night. I say similar because I might have fat fingered it - but I don’t believe so.

Experienced the immediate (unintentional) release after setting.

I was shuffling cars in the driveway, intending to jump out and back in pretty quickly… I’m glad I didn’t leap out* too quickly. Would have rolled into another car in the garage.

 

[DMV Supra]

I’d say for some reason…Everytime I turn on the vehicle, there is a 50/50 chance that the parking break releases. Not sure what’s going on

 

[puckshaw]

I haven’t had any issues with mine so far. I always park it in gear though out of habit.

 

[Joker328]

This is...concerning. Definitely report it to your dealers. Sounds like this could end up being recall worthy, and the sooner Toyota hears about it, the better.

 

[6SPDA91]

I've had no issues with mine. Just out of curiosity, were you in gear with your foot depressing the clutch.

The car will automatically release the parking brake if you go into first and start trying to move.

Just trying to rule out other scenarios.

 

[Kroberter]

I've had no issues with mine. Just out of curiosity, were you in gear with your foot depressing the clutch.

The car will automatically release the parking brake if you go into first and start trying to move.

Just trying to rule out other scenarios.

neutral just after pressing the clutch for engine start. Started it, lifted off clutch pedal in neutral and adjusted radio and when I looked up I was a whole car length forward out of the parking spot.

I’ve been experimenting and it is really inconsistent. Sometimes it holds the parking brake until I start letting out the clutch in gear to begin moving and sometimes it releases without selecting a gear. I’d love to see the If/then programs that are driving this behavior because I’ve tried every sequence I can think of and it does something different seemingly whenever it feels like it.

 

[6SPDA91]

neutral just after pressing the clutch for engine start. Started it, lifted off clutch pedal in neutral and adjusted radio and when I looked up I was a whole car length forward out of the parking spot.

I’ve been experimenting and it is really inconsistent. Sometimes it holds the parking brake until I start letting out the clutch in gear to begin moving and sometimes it releases without selecting a gear. I’d love to see the If/then programs that are driving this behavior because I’ve tried every sequence I can think of and it does something different seemingly whenever it feels like it.

Wow that really is odd behavior. I haven't seen that yet (luckily). Maybe it's a bad parking sensor and the dealer can diagnose the issue.

 

[Kroberter]

I confirmed the parking brake can release on its own.
Always place your MT in gear when you park. DO NOT TRUST the ebrake.

My wife and I parked at a rest stop. I made sure to set the ebrake and I got out, locked the car, did the obligatory backward walk while I stare at the machine I climbed out of. We did our business and as she came into view of the car, 5 or so minutes later she could see the car rolling forward. It luckily rolled into a low curb with no damage but could have been much worse if the slope was not in our favor.
I know I set the brake and the fact that it took minutes before it moved makes me think it randomly released while we were away. I took a good long look at it as I walked away too so I’m fairly certain MT owners need to be wary of this and always stick it in gear as well.

 

[XtremeMaC]

I confirmed the parking brake can release on its own.
Always place your MT in gear when you park. DO NOT TRUST the ebrake.

My wife and I parked at a rest stop. I made sure to set the ebrake and I got out, locked the car, did the obligatory backward walk while I stare at the machine I climbed out of. We did our business and as she came into view of the car, 5 or so minutes later she could see the car rolling forward. It luckily rolled into a low curb with no damage but could have been much worse if the slope was not in our favor.
I know I set the brake and the fact that it took minutes before it moved makes me think it randomly released while we were away. I took a good long look at it as I walked away too so I’m fairly certain MT owners need to be wary of this and always stick it in gear as well.

WTF. One of you MT owners will have to sacrifice your Supra for NHTSA/Toyota/BMW to do something about it.

Cross check with BMW MTs for sure before you roll it down a hill though.

 

[Spart]

As far as I can tell, this is related to the function that automatically disengages the parking brake if you try to drive away with it engaged. Steps to replicate:

1. Come to a complete stop with the clutch in, car in neutral.
2. Keep clutch held in.
3. Set parking brake, let go of brake pedal.
4. Let the clutch out.
5. Observe that the parking brake releases and you start rolling.

Edit: see post #47 for more concise instructions on how to replicate this, link: https://www.supramkv.com/threads/parking-brake-unexpected-release-mt.16262/post-272871

I have noticed that it will also only do this once. If you clutch in, foot brake, set the parking brake, release the foot brake, and release the clutch, it would not release the parking brake a second time on me.

That perhaps also means that if you don't manually disengage the parking brake before you drive off after starting the car for the first time (i.e. you let this system disengage the parking brake for you) that it may be defeated until the next time the car is turned off and back on again. That could explain some of the inconsistency. I'm not sure, I don't make a habit of trying to drive off with the parking brake applied because it's a bit slow to disengage.

The stupid part about this is that the car KNOWS it's in neutral, unlike some other cars with manuals that only know if they're in reverse or not. There should at least be a defeat on this that prevents it from working if the car is not in gear.

If anyone else can replicate these steps and confirm the problem, I think we've got pretty solid grounds to report this issue to NHTSA (several of us should do it in order for them to take action) to force Toyota/BMW to do something about it.

 

[CULaterJimzo]

As of late I’ve noticed my P-brake being released randomly too, not consistent on how its happening.
By starndard it would either turn off manually or when you start rolling .
To explain my experience. cold or warm start, clutch in, foot on brake, gear to neutral and start, the moment i disengage clutch it’ll release on its own. it would sometimes do this.
Other example it keep turning itself off everytime i disengage clutch.
Video is me just turning on the car and letting go of the clutch.

 

[DEupra]

As of late I’ve noticed my P-brake being released randomly too, not consistent on how its happening.
By starndard it would either turn off manually or when you start rolling .
To explain my experience. cold or warm start, clutch in, foot on brake, gear to neutral and start, the moment i disengage clutch it’ll release on its own. it would sometimes do this.
Other example it keep turning itself off everytime i disengage clutch.
Video is me just turning on the car and letting go of the clutch.

How about starting the car without having your foot on the brake pedal? Maybe the car auto disengages the parking brake when you depress the clutch while having your foot on the brake pedal and the car is assuming you are either ready to go or the car thinks since you have the brake pedal depressed it no longer needs the emergency brake.

In my mind, I would be most worried if the car decided to disengage the parking brake if my foot is not on the brake pedal while disengaging the clutch.

 

[CULaterJimzo]

Maybe the car auto disengages the parking brake when you depress the clutch while having your foot on the brake pedal and the car is assuming you are either ready to go or the car thinks since you have the brake pedal depressed it no longer needs the emergency brake.

opps i meant it would happen with and without foot in brake. ( was reading OP and got stuck in my head )

this morning cold start, foot on brake, it didnt turn off on its own. Had to manually press the button/gear clutch and go to turn off

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