Prius Brake Problem - CONFIRMED BY TECH

Discussion in 'Gen 2 Prius Main Forum' started by grinthock, Feb 3, 2010.

  1. tndriver

    tndriver New Member

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    I have had this happen on pot holes with my 2007 kind of makes your butt pinch the seat for a second don't it. not been a big problem for me though.
     
  2. qbee42

    qbee42 My other car is a boat

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    If my wife is with me, I always yell and say "Whoa, lost the brakes there for a second. Thank goodness we didn't hit anyone." It's become a joke with us due to all of the hysteria on this site.

    Tom
     
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  3. tndriver

    tndriver New Member

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    That is funny right there do not care who you are.
     
  4. okiebutnotfrommuskogee

    okiebutnotfrommuskogee Senior Member

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    I have noticed this on my Prius after hitting a hole or rough spot while braking, but it never has alarmed me because the Civic Hybrid that I owned for almost five years before getting the Prius new in 07 did the exact same thing. If you think about the situation it is easy to understand what is going on.

    The problem with the 2010 models may be something different, or maybe not.
     
  5. fastring

    fastring Junior Member

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    This is true stuff. I have a spot on my commute where I experience this 100% of the time:

    Driving ~25 to 30mph going up hill, on bridge that is a freeway overpass, where I turn into the left turn lane that has a stoplight that leads to the freeway on ramp. If the light is red or I need to slowdown for the turn, when my wheels go over the metal transition plate between the asphalt road and the concrete bridge, if I have my brakes on prior to the transition, the out of control light flashes , ABS engages and after the transition, I lose brakes for a second or two or maybe three. If the light is red it can be a little tricky as I need to stop for the light shortly after the transition. There are two lanes that turn onto the freeway and if someone shifts from one lane to the other for a better light position, it gets even trickier to stop on time.

    For those in San Diego, this is the light at La Costa in Carlsbad, going west on La Costa and entering the I-5 south on ramp.
     
  6. grinthock

    grinthock New Member

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    Fastring: EXACTLY!!

    It has to do with applying the brake BEFORE hitting the obstacle, and then once you clear the obstacle with the brake applied -- you lose brakes on solid ground.
     
  7. F8L

    F8L Protecting Habitat & AG Lands

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    All 5 of the 2000+ GM cars and trucks I owned did the same thing as my 2005 Prius. Not sure it compares to the 2010 problem though.
     
  8. apriusfan

    apriusfan New Member

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    People would seem to be wanting a car that stops evenly. Are you saying they are being unreasonable? BTW, every other car that I presently own (they are MY 2005+, from BMW and Volvo) manages to stop evenly on all surfaces - from washboard to pavement with wet clay overrun from rain washing off the hillside onto the roadway (which is a close approximation to ice).
     
  9. fuzzy1

    fuzzy1 Senior Member

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    I hope you can get the service manager and some higher level Toyota staff to ride along and feel it, then drive through it themselves. When there are doubts, there's nothing like getting the people with the power to do something to experience it.
     
  10. apriusfan

    apriusfan New Member

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    They could still engage in denial. It took a trip by a U.S. DOT representative to Japan to get the senior folks at Toyota to start taking the accelerator problem seriously. That bit of denial is probably going to cost Toyota a couple of million $ U.S. in fines.
     
  11. BBALLSTAN

    BBALLSTAN bballstan

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    The other day it was raining in Southern CA. I went to brake at a stop sign and my car just STOPPED and turned off!! The yellow brake skid light went on. I started the car again with no problem but very fearful that it would do that again. I took it right to the dealership and they couldn't repeat it. They checked it and said there was no problem.

    Today, sunny day, no rain and I went over a bump. The car's yellow light went on again but it didn't stop. I held my breath because I was driving on a busy road. HELP!! This is so scary!! Any suggestions?

    I need the car to get to work.

    Thanks.


     
  12. don_chuwish

    don_chuwish Well Seasoned Member

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    After dropping my kids off at piano lessons my wife and I head back down a long steepish hill. Speed limit is 35 but if I just let the car go it'll get to the mid 40s on one straight portion, so sometimes I have to lightly ride the brakes.
    On wet days (common enough here in Oregon!) if I go over one of the many manhole covers on the road I notice the brief loss of braking power. But it's nothing dangerous in my estimation. Even at 40mph downhill it's over and the brakes are back on task before I've had a chance to do more than blink in surprise. It is an odd feeling but that's about it. I'll have to try it in the Odyssey one of these days, see how it compares.

    - D
     
  13. apriusfan

    apriusfan New Member

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    Out of curiosity, how many PCers (in the U.S.) who have experienced brake problems have filed a report with NHTSA?

    If you haven't filed a report with NHTSA, I wouldn't expect to see any resolution of your brake problem any time soon.
     
  14. grinthock

    grinthock New Member

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    aprisufan: In Canada I would have to approach transport canada -- which I have yet to do..

    So... Looks like Toyota is admitting a problem on the Prius..

    Toyota says Prius had brake design problems - Yahoo! News

    However looks like it's GEN III and not GEN II cars that they are talking about.

    Good news! The largest local TV station here in Toronto is coming to do a story on it at my place today, I will capture it, and upload it for everyone to see.



    This sound familiar?

    "He said when the ABS was in operation, there was a small delay switching from regenerative braking - which captures the energy of the car's motion to recharge the battery - to the hydraulic brake."

    Also said by Toyota

    "When the car moves on a bumpy or slippery surface, a driver can feel a pause in the braking when the vehicle switches between the traditional hydraulic brakes and the electronically operated braking system, he said."


    This doesn't sound 100% like the same problem to me - but it is a step in the right direction. This is my last day of vacation so today is my last day to really spend some time highlighting this locally...
     
  15. dapastaguy

    dapastaguy Junior Member

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    I have noticed this issue in my 08 when braking on uneven road services. I must say that your advice on how to create are a little extreme. The ESC light will flash when I am braking over uneven ground at approx. 20 mph, the brakes do not stop working, and the vehicle stops fine. If Toyota comes out with a fix fine, if they don't that is also fine as I do not consider this a dangerous issue for me.

    I have also tried to make my floor mat slide up and jam the gas pedal, it just ain't possible, and I still have the mat installed. Maybe the 2008 was not affected, maybe it was, again no concern to me.

    I had a 2001 Ford Explorere Sport Trac previous to my Prius. It was a great vehicle, no major maintenace issues, but I could not afford gas at approx. 16 mpg.

    I have not owned a GM vehicle for over 25 years. My wife currently has a Chevy Cavalier, and it is junk. I would never switch to GM from Toyota.

    So, having owned this Prius for 2 years, and having driven Toyotas in general for 15 years of the 35 I have been driving, I still think they are the most dependable of all makes, with Ford being 2nd IMO (I have only owned 1 but it was great). Toyota has long had a record of dependability, and the recent issues will be fixed, so let's not all jump ship here
     
  16. ystasino

    ystasino Active Member

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    Count me with the people who momentarily (1 s) lose front braking power over uneven surfaces. This is more frequent when I brake before the uneven surface.

    I would only consider it a major problem if I had to drive over uneven surfaces. I don't expect that many people face this issue.

    In my opinion Toyota tried to implement a system that balances a slipping wheel and they failed. This might be more dangerous in the US where people rarely keep safe driving distances.

    If they could disable the VSC I would be happy.

    Also count me with the people who are not switching to GM before they prove their new attitude in the next 10 years.
     
  17. grinthock

    grinthock New Member

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    ystasino: Your point is right, The problem is specific to braking BEFORE the uneven road surface. then you get onto the uneven surface while braking - the ABS goes nuts and you have far les brake power than you should, and even after you re-enter the smooth road, for a moment the ABS is still pulsing like mad and you have no brakes.
     
  18. ystasino

    ystasino Active Member

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    EDIT: Until I find written confirmation of the NHTSA investigation

    "into allegations of momentary loss of braking capability while traveling over uneven road surfaces, potholes or bumps"

    involves Gen II Prius cars I am recalling :)o)the account of the conversation I heard this morning on MSNBC.

    Current articles suggest that Toyota recalls only Gen III vehicles; however, it is not clear that the NHTSA will only look into Gen III vehicles alone.

    http://www.msnbc.msn.com/id/35214248/ns/business-autos/

    ---------------
    Initial post:

    NHTSA: Formal investigation for momentary loss of braking over uneven surface about
    Generation II. About 140 complaints and 4 crashes.

    Saw it on MSNBC

    That helps with my Prius resale value :(

    Again I don't consider it "stop driving" problem because it's something I knew about for 33 months. It has been a minor concern though.
     
  19. don_chuwish

    don_chuwish Well Seasoned Member

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    I haven't decided that it's a problem worth reporting.

    - D
     
  20. edthefox5

    edthefox5 Senior Member

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    Good post. Excellent explanation.

    I have experienced what the OP posts also. Hit a manhole cover or good bump and get a alittle rear wheel hop just when your trying to pull the car down quickly and essentially it feels like the brakes are shut off for a second or two. Quite thrilling there!!

    I wonder if its exacerbated by both the light weight of the car and the tiny tire footprint?
    But the car does stop well after that I second period. It has made me pay more attention and slow down around town a little.
     
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