Parking Brake unexpected Release (MT)

[roddrsw]

That's really odd, looks like real factory issue. Mine doesn't ever did that and I know other MT owners and never heard about it...

It does release automatically but only when I'm in gear and start releasing the clutch

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[Spart]

That's really odd, looks like real factory issue. Mine doesn't ever did that and I know other MT owners and never heard about it...

It does release automatically but only when I'm in gear and start releasing the clutch

Try doing everything the same but go to neutral and try to drive away as if you were in first.

 

[roddrsw]

Try doing everything the same but go to neutral and try to drive away as if you were in first.

Do you mean like try to literally move by pushing the car forward while running and in neutral? Lol

I always when I turn it on, I release the clutch (while in neutral) and go either setup my music or navigation. It never released the parking brake by itself

 

[94boosted]

I just came across this older thread as I went searching to see if others have had this problem.
My 23 MT does this same thing. I turn the car on, take my foot off the clutch and the parking brake releases.
I’m used to it now so I just always keep an eye on it, but I was hoping it was a setting that could be fixed.
This definitely startled me the first time it happened because I was on a slight decline but I learned quick ?

I've just gotten in the habit of following the process below and have never had it release on me:

1. Neutral
2. Foot on brake pedal
3. Set parking brake
4. Foot off brake pedal
5. Turn off car
6. If I'm on a hill, and only then, I'll also throw it in gear to be safe

 

[Spart]

Do you mean like try to literally move by pushing the car forward while running and in neutral? Lol

No.

The car releases the parking brake automatically when you try to drive away with it on. This is a known "feature" and it doesn't have enough safety interlocks to prevent it from activating when it shouldn't, resulting in a rollaway condition.

So just as if you're taking off, let off the foot brake, feed in throttle, and slip the clutch. But be in neutral instead of 1st/reverse. See if the parking brake disengages. Then try it again in 1st/Reverse.

My car does not care that it's in neutral. I can come to a stop in first with the clutch in, set the parking brake, shift to neutral, and then let out the clutch (as if to park with the engine running) and the car disengages the parking brake even though I just set it. It does this almost every time.

 

[roddrsw]

T

No.

The car releases the parking brake automatically when you try to drive away with it on. This is a known "feature" and it doesn't have enough safety interlocks to prevent it from activating when it shouldn't, resulting in a rollaway condition.

So just as if you're taking off, let off the foot brake, feed in throttle, and slip the clutch. But be in neutral instead of 1st/reverse. See if the parking brake disengages. Then try it again in 1st/Reverse.

My car does not care that it's in neutral. I can come to a stop in first with the clutch in, set the parking brake, shift to neutral, and then let out the clutch (as if to park with the engine running) and the car disengages the parking brake even though I just set it. It does this almost every time.

Tested, and my parking brake only releases automatically IF I'm 1st gear or reverse.

 

[Spart]

Tested, and my parking brake only releases automatically IF I'm 1st gear or reverse.

That's what I wish mine would do.

 

[morte]

A couple of months ago, I managed to replicate this problem with a Toyota mechanic sitting next to me. Toyota engineers had the dealer replace the clutch release cylinder and send the old one to them for investigation. This didn't solve the problem, but at least it got the ball rolling on an investigation. They also had a MT Supra in Hawaii under investigation for the same problem. I haven't heard anything since, but at least they have seen the problem and have a TAS case for it. I did not get a case number.

My replication scenario is to release the clutch while shifter is in neutral and brake is on, and 80% of the time that will cause the brake to release. I haven't found any other factor that influences occurrence.

 

[Spart]

A couple of months ago, I managed to replicate this problem with a Toyota mechanic sitting next to me. Toyota engineers had the dealer replace the clutch release cylinder and send the old one to them for investigation. This didn't solve the problem, but at least it got the ball rolling on an investigation. They also had a MT Supra in Hawaii under investigation for the same problem. I haven't heard anything since, but at least they have seen the problem and have a TAS case for it. I did not get a case number.

My replication scenario is to release the clutch while shifter is in neutral and brake is on, and 80% of the time that will cause the brake to release. I haven't found any other factor that influences occurrence.

It's my belief that there are *some* interlocks (or conditions) on the system that have to be met.

I believe one of them is that you have to have recently touched the throttle and brakes.

There also seems to be some conditionality around doing it multiple times in a row, or if the vehicle was recently started.

I can replicate it 100% of the time if I am rolling along at 20-30, come to a stop with the clutch pushed in (I usually downshift or heel-toe, which starts that timer for the "recently touched the throttle" condition) and set the brake then immediately let the clutch out.

Confounding this slightly may be the fact that I'm in the habit of heel-toeing, and even if I don't heel toe, I still place my big old feet on the brake in position to blip the throttle if needed. So it's possible that I'm actuating the throttle like 1-2% - not enough to notice the revs do anything, but enough to satisfy the interlock if it exists.

But the real problem here is that the car knows it's in neutral and it activates the system anyway. It should never activate in neutral due to the rollaway vehicle hazard.

If you've had this problem, please please please report it to NHTSA. It doesn't take much of your time.

https://www.nhtsa.gov/report-a-safety-problem#index

 

[lucky phil]

Does the "drive ready" state on or off buy into this? Section 2.1 page 36 in the owners "quick reference" section.

Phil

 

[FLtrackdays]

Maybe another button would help

 

[morte]

It's my belief that there are *some* interlocks (or conditions) on the system that have to be met.

I believe one of them is that you have to have recently touched the throttle and brakes.

There also seems to be some conditionality around doing it multiple times in a row, or if the vehicle was recently started.

I've had it happen to me on a cold start, no throttle or brake action. Have also had it to me after the car was running for a while. When I replicated it for the tech, I made sure to keep my right foot away from the throttle and brake, and the car had been sitting for a little while.

I thought that there was maybe something going on with data coming in from the throttle sensor, but Toyota pulling the clutch release cylinder threw a lot of cold water on that. Next week I'll get in contact with my service advisor and see if he has any updates to share.

If you've had this problem, please please please report it to NHTSA. It doesn't take much of your time.

https://www.nhtsa.gov/report-a-safety-problem#index

Done.

Does the "drive ready" state on or off buy into this? Section 2.1 page 36 in the owners "quick reference" section.

Phil

Can't replicate it with the engine off. Although weirdly, when I tried doing so, then turned the engine on, I couldn't replicate it as usual. Weird.

 

[swrdply400mrelay]

Anyone have a 2024 and have this happen?


ETA: I tried this (as outlined in post 47 with doors closed) on my 2024 and it didn't happen. Tried twice.

 

[Spart]

Anyone have a 2024 and have this happen?


ETA: I tried this (as outlined in post 47 with doors closed) on my 2024 and it didn't happen. Tried twice.

Follow along with how I replicated it here and see what behavior you observe:

 

[swrdply400mrelay]

Follow along with how I replicated it here and see what behavior you observe:

Didn't do it either

I was in neutral, pushed clutch and gave gas, PB was still on.

Tried again, in N, pressed clutch, then pressed brake and gas, then de-clutch, PB still on.

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