Data on "brake loss" (aka "sudden acceleration") after bump

Discussion in 'Gen 2 Prius Technical Discussion' started by 2009Prius, Apr 27, 2011.

  1. jstraw20

    jstraw20 Member

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    I think I'd need a motion sickness bag if I tried this!
     
  2. 2k1Toaster

    2k1Toaster HID Guru

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    Not if you keep your eyes shut. Motion sickness is usually because things don't line up. Your brain gets confused. But if there is no vision to counter the eardrums, you shouldn't be sick (if you are prone to be sick to begin with).
     
  3. VoicesInMyHead

    VoicesInMyHead New Member

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    Not to hijack the thread, but as a chronic motion sickness sufferer from inner-ear damage from meningitis, I can say with authority that you can most definitely have motion sickness, even with your eyes closed. It sucks.
     
  4. fuzzy1

    fuzzy1 Senior Member

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    Ditto for genetic inner-ear issues. Motion sickness is very easy to achieve with eyes closed.
     
  5. xs650

    xs650 Senior Member

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    That sounds backwards. If you are in a windowless cabin on a ship it's worse than if you can see the horizon so your brain agrees with your inner ear.
     
  6. 2k1Toaster

    2k1Toaster HID Guru

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    Well then I must be backwards. The only time I have ever felt motion sick is when I had an ear infection and the world was spinning when i wasn't. Shut my eyes, and all was well.

    Perhaps different from those with chronic sickness.
     
  7. cwerdna

    cwerdna Senior Member

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    Are you referring to SSC-A0B that only applied to the 3rd gens (2010 models produced before the production change sometime in January 2010)? That did become a recall.

    For the 2nd gen, unless I've missed something (or it didn't apply to my 06), I don't think there was ever an update. There was even this post about the 2nd gens: http://priuschat.com/forums/prius-h...call-little-more-information.html#post1060629.
     
  8. liskipper

    liskipper Member

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    This confirms what I have always believed about the loss of braking - it has nothing to do with the BS explanation given by Toyota that it is the way that ABS is supposed to work, but is a defect in the system itself causing regen to stop when going over a bump. I encourage everyone who has experienced this problem as I have to post it with the NHTSA here: https://www-odi.nhtsa.dot.gov/ivoq/
     
  9. dogfriend

    dogfriend Human - Animal Hybrid

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    And so it begins.
     
  10. jdcollins5

    jdcollins5 Senior Member

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    Don't confuse me with facts, I have made up my mind :D
     
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  11. jdcollins5

    jdcollins5 Senior Member

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    2009Prius

    Off topic, but how has your PriiDash project come along? Have you ever decided to make this available to others?

    Thanks,

    Dwight
     
  12. 2009Prius

    2009Prius A Wimpy DIYer

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  13. cwerdna

    cwerdna Senior Member

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    Sigh... Not this again! [​IMG]

    There are hundreds of posts over MANY threads over this in the 3rd gen area and well, you guys got your SSC-A0B recall. If you still don't like it and feel that a true safety issue remains, fine, file a safety complaint. Same goes for the 2nd gen (but there was no software update).

    The OP posted his data on his 2nd gen and this is in 2nd gen area. I hope you realize that the braking system is quite different between the 2nd and 3rd gen and Toyota claims that 90% of the HSD system was newly developed/redesigned on the 3rd gen.

    As a side note, Bob Wilson did post this somewhat confusing poll at http://priuschat.com/forums/gen-iii-2010-prius-main-forum/74199-poll-prius-brakes-problem.html prior to SSC-A0B being announced and before the running production change to 3rd gens happened.

    My vote (from http://priuschat.com/forums/gen-iii...99-poll-prius-brakes-problem.html#post1031776) was:
    Interestingly, http://green.autoblog.com/2011/04/19/countdown-to-earth-day-regenerative-braking-102/ sort of discussed the scenario that could cause the switchover.

    I do also recall previous chatter about it being done to protect against voltage fluctuations. From http://www.evworld.com/library/toyotahs2.pdf :
    Yeah... Unfortunately. :/
     
  14. qbee42

    qbee42 My other car is a boat

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    Yes, I was referring to the Gen III recall. The Gen II never exhibited this behavior to the extent shown by the Gen III.

    Quite the contrary. This data shows that it is regen cutting out over a bump. It's not a defect, it's simply an artifact of braking with only two wheels.

    Tom
     
  15. uart

    uart Senior Member

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    Or to put it another way. If braking on a rough or uneven road surface you may need to adjust your braking effort (force on the brake pedal) as you're stopping.
     
  16. moresee11

    moresee11 New Member

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    just curious as anyone who thinks that the brake loss or sudden acceleration ever experience the ABS releasing the brakes while coming to a stop on a hill on a dry day. I have. I know this may or may not be related to the brakes switching but increase in braking distance as you approach a cross walk is not an acceptable "response" from any car. I am just waiting to sell my 2010 unless Toyota fixes this problem. I tried to find another thread on this topic but I couldn't. This has happened many times and is not a feeling or sensation but an actual release of the brakes at less than 5mph by the ABS. If anyone can help, please chime in or point me to the thread

    note brake complaints are still being reported

    2010 Toyota Prius Electric Brake Complaints
     
  17. cwerdna

    cwerdna Senior Member

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    Any reason why you posted this to a Gen 2 thread? You have a Gen 3.

    What was the build date of your 2010? If it was an early 2010 before the running change, then you need to have SSC-A0B (aka brake recall firmware update) applied. More info at FAQs on the 2010 Prius Recall | PriusChat. There are a ton of threads on this on the 2010 where this topic has been beaten to death like http://priuschat.com/forums/gen-iii...ot-into-accident-today-due-brake-problem.html, http://priuschat.com/forums/gen-iii.../78515-recall-brakes-did-not-fix-problem.html, http://priuschat.com/forums/gen-iii...ot-resolved-even-after-dealer-correction.html and http://priuschat.com/forums/gen-iii...eshooting/72650-felt-brake-cut-out-thing.html others....

    If you already have the change, if you truly think it's a problem, file your own safety complaint w/NHTSA then you may as well sell your Prius now, to take advantage of the price spike/low supply and relatively high gas prices.
     
  18. SageBrush

    SageBrush Senior Member

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    Vertigo is a complicated symptom. The brain interprets signals from vision and the inner ear. Incoherence leads to the symptom. For most causes shutting down the faulty signal solves the problem.
     
  19. qbee42

    qbee42 My other car is a boat

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    Sell now. The market is hot for Prius, and I can guarantee that there will be no fix for this problem. What you perceive as a problem is just physics, so it won't be "fixed". Cut your losses while you can and move on.

    Tom
     
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  20. fuzzy1

    fuzzy1 Senior Member

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    This contentious issue has been discussed very heavily in the GenIII forums, not here in GenII.

    This happens at less than 5 mph? Are you sure that it isn't the normal but less-than-seamless switchover from regenerative braking to pure friction that happens at 7 mph?

    If the later, I experience it only with light to moderate braking, when braking distance is not important. When braking distance is important, drivers are usually applying hard braking, which is always friction braking. I have never felt this release under those conditions.

    If this is what you are feeling, and it is still unacceptable to you, I'll echo the comments to sell the car now, while the value is high. There are plenty of others who can readily adapt to this feeling.
     
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