How can there be ANY runaway Prius'es if they have brake override?

Discussion in 'Gen 3 Prius Main Forum' started by alokeprasad, Mar 10, 2010.

  1. alokeprasad

    alokeprasad Member

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    Other threads have pointed out that Prius's already have a brake override function (engine power is cut if both pedals are pressed).

    So, the only possibilities that allow runaway Prius (for ANY reason, carpet, sticky pedals, or whatever) are:

    1. the override system is malfunctioning or
    2. the brake pedal was never pressed (despite what the driver thinks)

    It should be easy to determine 1. and no one has claimed that the override was defective. That would leave only 2. as the explanation.
     
  2. paulsha911

    paulsha911 Junior Member

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    The CHP officer reported that he could smell the burning brake pads, and that it was an indication to him at the time that the driver was trying pretty hard to stop the car.
     
  3. alokeprasad

    alokeprasad Member

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    Then the override system failed. It either is a persistent problem, in which case it will be easy to test the vehicle, or an intermittent problem (a tougher case to solve).

    The EDR data will be a big help in understanding this.
     
  4. TheSpoils

    TheSpoils Member

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    How does the CHP (with all due respect) know the difference in smell from the brake, engine, exhaust or antifreeze overflow, which are all possible smell producers in a high speed event?
     
  5. Creaky

    Creaky Still motorin...

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    Here's a thought to consider:

    Perhaps he tried to engage the emergency brake which produced the burnt brake pad smell.

    Which sets of brakes does the emergency pedal link into, the front or the back?

    Whichever, all that needs to be checked is if all 4 sets of pads, front and back are burnt.

    If not, then he attempted to slow down with the emergency brakes which aren't tied into any electronic means of control.

    Anyhow, forensics should be able to show when the brake pedal and gas pedals were depressed.

    I for one am interested in hearing the outcome of this one.
     
  6. Fuel Miser

    Fuel Miser Junior Member

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    I'm not sure about you, but I can easily tell the difference. All it takes is an experience. Each of these components let off a very distinct smell, that once you've smelled it, and been told what it was, you can then identify it in the future.

    Coolant produces a sweet smell, hot exhaust sulfer smell, and brakes are just nasty pungent, you can almost taste it.
     
  7. alokeprasad

    alokeprasad Member

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    Do we all agree with my premise? On vehicles with brake override, either the override system failed or the driver did not apply the brakes.

    Makes it easier to investigate the failures (the focus would be the brake override system).
     
  8. pjksr02

    pjksr02 Active Member

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    Here's a stupid question: Has anyone tried to hit their brakes while still depressing their gas pedal?

    I have. The engine still accelerates! I was surprised. There is no "lock out" override on my 2010 Prius. Try it! (I was going up a hill at about 40mpg when I tried this.)

    That said, shifting into neutral does work, and solves this potential problem...
     
  9. brad_rules_man

    brad_rules_man Hybrid electric revolutionizer

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    It seems to have failed. :( I REALLY feel that if he had pushed and held the power button, or shifted into neutral or even reverse.. then the car would have went into neutral and coasted.

    Sad really.
     
  10. ScottG10

    ScottG10 Member

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    Or, Stikes could have been riding the brakes in an effort to overheat them and lend credibility to his claims. This inturn would support his case to get something free from Toyota. Or, maybe he just thrives on attention.
    I know thats harsh but his story is very suspicious.
     
  11. Prius 06

    Prius 06 Member

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    The answer: "He's not a mechanic, so he wouldn't"
     
  12. ryung2003

    ryung2003 New Member

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    We all here own a Prius. I bought my Prius in Mid-January & everything seemed fine, even though I took it back for the recall & had them fixed. I believe that driver speeded nearly 100mph. For my understanding, Prius do need to take time to slow down its speed & not made for the crazy drivers who want to speed. If he drives 55-60mph or follows the speed limits, it shouldn't have any problem (burning smell & couldn't stop the car?!!) on his Prius. Most of us know that a car wouldn't accelerate its speed on its own, it's always the drivers! Therefore, I wouldn't take it seriously everything what he said about Prius! I don't know if he wants to use this excuse for not getting a speeding ticket because now it costs between $300-411...

    Here are some of my safety tips of driving a Prius:
    1) Keep the distance (the length of a car) between your car & the one in front of yours in case any accidents might happened.
    2) Drive slower & reduce the speed if you're driving during busy hours or in poor weather conditions.
    3) Follow the speed limits.

    Toyota might have some issues that didn't want us (consumers) to know but I'm sure that they are investigating & trying to solve the problems in Prius.
     
  13. ryung2003

    ryung2003 New Member

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    :focus: I totally agree!!! I feel suspicious about his driving skills instead... :rolleyes:
     
  14. Prius 06

    Prius 06 Member

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    My guess is this goof drove with the parking brake partly on, to give the smell.
    The officer said he could smell the brakes, see the lights on and see brake dust.
    Well, it would be easy for the dust...just leave it for a few weeks and it builds up anyways. Rest his foot on the brake for the lights to come on.
    The other thing the cop said is that he could tell he was braking hard. HOW? He could of been stepping on the floor (foot behind the pedals).

    As soon as I heard this story (with very little details) I said to the wife as we were driving in our 06, BS....and I still stick to this story
     
  15. ScottG10

    ScottG10 Member

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    Mechanics are not educated as to what burnt brakes smell like. They are like the rest of us ~ once you have smelled burnt brakes you will always be able to distinguish it. It's a one of a kind smell and I completely trust that a police officer would have smelled this many times in his career.
     
  16. ScottG10

    ScottG10 Member

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    I'm going to try mine tomorrow, but I'm curious, did you have the recall done on yours?
     
  17. mad-dog-one

    mad-dog-one Prius Enthusiast

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    Part of their special trianing, you know ... the long nose of the law.
     
  18. TheSpoils

    TheSpoils Member

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    This has been posted, but i will post again;
     
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  19. Prius 06

    Prius 06 Member

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    Perhaps in the US, but not here.
    And as I stated before, thats exactly what they would use in court....again, at least here.
     
  20. pjksr02

    pjksr02 Active Member

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    No, Scott. I'm not concerned at all about the brakes or the accelerator, actually. I'll get the update next time I'm near a dealer, though, just for liability protection.

    I had thought there was an override, and like I said, was very surprised when my brake application did not stop powertrain output. With the connection between the regenerative braking and powertrain, it really doesn't seem there couldn't be an override. In fact, there is a thread here, that has been closed, where Toyota states that all hybrids have a version of the brake override.

    My conditions, more specifically, were that I was climbing a hill (maybe 6% grade), in the Power section of my HSI, in Eco Mode, about 40mph. I didn't really lay into my brakes, just pressing them moderately; I didn't think to look to see what my HSI monitor did during this, but will look next time. My Prius is a III, the 59,000th off the line.
     
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