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Understanding your braking system

Discussion in 'Gen 3 Prius Main Forum' started by hobbit, Feb 3, 2010.

  1. Rhino

    Rhino New Member

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    I correct myself.

    "Of course, when the brakes becomes momentarily unresponsive, you lose both the safety margin in distance and the safety margin in using additional braking force [during the momentary part. It comes back and is generally sufficient to stop the car in time since most people who experience it do not crash. The temporary feel of losing braking is what's causes people to be concerned. And rightly so. They don't know if it is the beginning of a slow decline (a bad problem going to get worse), a malfunction, or just normal. Silence on the part of the manufacturer does not help.]"
     
  2. KK6PD

    KK6PD _ . _ . / _ _ . _

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    and all the witches too......burn 'em......
     
  3. asv

    asv New Member

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    The braking flaw on the Prius is not a quirk, its a defect, and a huge safety hazard.
     
  4. mitch672

    mitch672 Technology Geek

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    Wrong. It is not much different than it was on the Gen 2 Prius.
    The "defect" is in the new drivers, not knowing what to expect, and thinking the braking should "feel" exactly the same on a traditional car. Newflash, it doesn't, and probably never will.

    If the "fix" for this issue is to lower the effectivness of the regenerative braking system, and enable the hyrdaulic(friction) braking system sooner, I will opt to NOT get the fix, thank you.

    That is really the only thing they could really do, being a software/firmware modification.

    I can't believe the number of people who are bellyaching about this. no one has crashed or been in an accident because of this, at least not published to date. Your prius has BETTER, more EFFICIENT brakes than a regular car, and it recaptures a lot of what would be otherwise be lost energy via the regenerative braking system. This is just one of the ways the MPG is improved.

    Mitch
     
  5. DeanFL

    DeanFL 2010 owner - 1st Prius

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    OK, so just train a relative or your kids if they drive your car:

    "the braking doesn't "feel" exactly the same on a traditional car. It doesn't, and probably never will. This prius has BETTER, more EFFICIENT brakes than a regular car, and it recaptures a lot of what would be otherwise be lost energy via the regenerative braking system. This is just one of the ways the MPG is improved."

    And don't worry because "no one has crashed or been in an accident because of this, at least not published to date."


    Perhaps print out a warning label for the dash too... That should get them through with no bellyachin'..

    I completely disagree with you. This is a defect and must be fixed. Drivers should not have to compensate for a design defect. And if this is not corrected professionally and rapidly by Toyota, sales will be impacted dramatically. Seriously bad publicity and competitive fodder. I'd guess Toyota will do the right thing.


     
  6. asv

    asv New Member

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    Mich, I well aware of how the regenerative braking system works. I really don't need a lengthy explanation thats already been regurgitated throughout this forum.
     
  7. efusco

    efusco Moderator Emeritus
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    My opinion...
    1) I'm glad they're going to adjust the software to smooth the regen to hydraulic transition.
    2) Whether it's a true safety issue is much more a matter of opinion than fact. I can imagine the rare situation where a driver not allowing adequate stopping distance could collide with a pedestrian or have a low-speed impact with another vehicle.
    3) I do not believe this is in any way a major safety issue excepting the above.
    4) Toyota handled this poorly, as they did the accelerator issue and are paying the price now with all the negative press. Someone clearly recognized that this braking sensation was abnormal and more significant than the Gen II, made software changes to account for it, but did NOT notify all the previous buyers of that fact in a timely fashion--boo on Toyota. I haven't searched, but there must be brake cut-out reports here from months back and it's clear that Toyota's been looking at is since December, and yet chose not to make the information public in a controlled manner that would have avoided the hysteria--poor poor choices.
     
  8. a1a1a1

    a1a1a1 Member

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    My man, these statements are so incorrect on so many different levels it is hard to decide where to start.

    First thing is that I am going to implore you to get whatever fix comes out immediately, not just for your personal safety but for the protection of your pocketbook. If you do end up in an accident after ignoring a critical safety system recall, and something really bad happens, you are going to be the corporate insurance company's fall guy, at fault, "whether you like it or not," as Gavin Newsom says.

    The "fix," as it is so aptly known, is to move three lines of code around in a computer program. It is to apply the hydraulic braking system in advance of cutting out the regenerative system. There will be a slight overlap of a few hundred milliseconds in some limited situations which is hardly a factor in efficiency. However, it will guarantee that some braking system is solidly in effect without a cutover delay.

    With all the smoke and noise, do we really know the extend of things? Do you trust Toyota now to babysit your daughter, let alone your Prius? As for those who have never experienced an accident due to braking issues, decide for yourselves, related or not: Seattle News - The Flip Side of the Perfect Prius - page 1 . Are you sure this happens by itself in limited situations without compounding factors? Take it easy!
     
  9. Darwood

    Darwood Senior Member

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    "With all the smoke and noise, do we really know the extend of things? Do you trust Toyota now to babysit your daughter, let alone your Prius?"

    Babysit your daughter??? Really? Do you fearmongers have no limits?

    I trust the safety of the Prius more than I trust that of a group of trolls engaged in a coordinated attack.
     
  10. mitch672

    mitch672 Technology Geek

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    If you are all so upset with your 2010 Prii, I suggest you sell them, take the huge loss and move on. Please stop whining & complaining, and posting thousands of times about this issue. I for one will be keeping my prius, and if there is a TSB and I am notified (which I would not expect for months, BTW), It will be done, since the dealer always applies any TSB's to your car, when you bring it in for normal service/oil changes.

    I am just not worried about this, and refuse to make a federal case out of it, the hysteria is way out of control, and I do feel most of it is politically motivated.

    FYI, I was waiting to buy a Chevy Volt, but I really lost interest/faith in GM, and I have serous doubts they will ever produce the Volt, in large enough quantitys that the "average joe" will ever be able to buy one, and the $40K+ estimated price tag was also not enticing, and buying a Gen1 product from GM is not the same as buying it from Toyota.

    Mitch
     
  11. The Electric Me

    The Electric Me Go Speed Go!

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    Yes, but this is a braking issue. Which I think changes the importance. If Toyota implements a change to how the Verticle Cargo net is attached...I don't think they necessarily need to inform everyone immediately. But imo, you change the software controlling how the brakes react? Then you MUST inform everyone and offer a way that those that have already purchased can get the update.

    We can just disagree on this, but IMO Toyota has handled this very poorly.
     
  12. DaveShepherd

    DaveShepherd Member

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    +1

    I am happily driving my 2010 Prius in snowy, icy weather with no worries whatsoever. I do not tailgate, I do not do all my stopping in the final 30 feet.

    Everybody needs to come in off the ledge.
     
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  13. silverfog

    silverfog New Member

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    So's a squeaking brake.
    Occasionally with my 2010 I brake lightly, feel an apparent slippage and so brake harder. What's the problem?
     
  14. wick1ert

    wick1ert Senior Member

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    I see this issue as a safety issue, but not as a "blow it out of the universe" safety issue as some make it out to be. Anytime a "safety" item is not functioning seamlessly (as this should) then it becomes an issue. If the brakes work one way on a typical, dry surface, the expectation is that it will function the same way on a rough / wet / slippery surface. Will it stop the car in the same distance on that surface? No. It should, however, not provide the lack of braking power.

    I feel that any update, etc. done to a safety function of the vehicle (steering, braking, accleration, etc) SHOULD be communicated immediately to the entire consumer base (owners, dealerships, etc).

    So, would I get rid of my 2010 Prius? No. Will I still drive it everyday without worry? Yes. Will I get any updates done for this? Yes.

    The issue isn't whether you are able to adjust to the sudden cut-out of the braking system, but that you should not have to. This is the reason why it's become an issue.

    I'm not here to bash Toyota, or defend Toyota. They have a requirement to the safety of their owners and I personally feel they may not have met that requirement in the manner that they should have. It is what it is now, and it's time to move forward.
     
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  15. The Electric Me

    The Electric Me Go Speed Go!

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    LOL! You think you could take a smaller portion of my quote a little more out of context?

    My comments aren't based on what you are personally experiencing or even how you want to feel about it. My debate is over how Toyota has poorly handled the software update...not the brake problem itself. If your happy driving your automobile in whatever state it's in? Fine. ....Since you don't think you have a problem I guess you won't be taking your Prius in for the software update "if and when" Toyota decides to share that with you.
     
  16. bighouse

    bighouse Active Member

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    Thank you for your post. I do understand my braking system.

    I also understand that Toyota has now come forward with recognizing this as an issue that requires an adjustment in the car. I also understand that this will likely be available in the near future and I understand that it will quite likely address the issue myself, and others, have experienced with the car.
     
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  17. tpfun

    tpfun New Member

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    Thanks for the interesting detail.
    This would have a negative impact on city mpg numbers. Did Toyota overemphasize fuel economy over common sense ?
     
  18. bwilson4web

    bwilson4web BMW i3 and Model 3

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    Source?

    Thanks,
    Bob Wilson
     
  19. qbee42

    qbee42 My other car is a boat

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    The "three lines of code" doesn't even exist on the same ECU. Braking on the Prius involves inter-processor communication between multiple ECUs, which is just a tad more complex than the simplistic example above.

    Tom