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On start up brake pedal drops to floor

Discussion in 'Prius v Care, Maintenance and Troubleshooting' started by fuzzylogic, May 8, 2013.

  1. fuzzylogic

    fuzzylogic New Member

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    Hello, my Prius v has about 18,000 miles and almost since the beginning, about 1 out of ten times upon start up, the brake pedal sinks completely to the floor. If the pedal isn't depressed completely an electrical arcing sound occurs. I have twice requested that the service department check this problem, particularly in the light of the Prius's brake history, and on the second round the service department decided it needed a new master cylinder. They were ready to install, but Toyota put the brakes on (at least they worked for them), siting that no brake problems were recorded on the computer diagnostic.
    Toyota also said this was "normal" when the car was cold, but it happens even when the car has been driven and is warm. This has never happened when the car is in motion, but I have read it has happened to people who's brakes eventually fail while driving.

    Does anyone have any insight or advice on this situation? Of course it's nerve-wracking to think one is sitting on a time bomb waiting for the brakes to fail while the car is in motion.
     
    #1 fuzzylogic, May 8, 2013
  2. -1-

    -1- Don

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    :oops:WOW, sounds like an accident waiting to happen. Problems that are hard to duplicate, are difficult to troubleshoot. Hopefully someone with expertise can offer suggestions.
     
    #2 -1-, May 8, 2013
  3. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    I can't imagine that this is not a dealer, warranty, issue
     
    #3 JimboPalmer, May 8, 2013
  4. Paradox

    Paradox Prius Enthusiast / Moderator
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    OP, do you own a Prius v or c? Your profile says c but your post says v. If yo own a c, you posed in the wrong forum. Let me know here and I will move the post, do not post again in the c forum. Thanks.
     
    #4 Paradox, May 8, 2013
  5. moeu

    moeu Junior Member

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    I think Toyota needs to take a look at the computer diagnostic system that it cannot pick up intermittent problems. I will never buy another Toyota.
     
    #5 moeu, May 8, 2013
  6. css28

    css28 Senior Member

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    You ought to visit the NHTSA website and log that as a safety issue complaint.
     
    #6 css28, May 8, 2013
  7. fuzzylogic

    fuzzylogic New Member

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    Yes, I own a Prius v. I have since changed it in my profile.
     
    #7 fuzzylogic, May 8, 2013
  8. Paradox

    Paradox Prius Enthusiast / Moderator
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    Ok, Thanks. I fixed it for you in your profile because you chose 2012 Prius for the vehicle year and V for the model.

    It's 2012 Prius v wagon for the year from the dropdown menu and then you can go in your profile again and choose two, three or five for the model since I don't know which one you have. Also, just as an FYI, Prius v is a lowercase v. Uppercase roman numerals were only used for model designation in 2010. yep, Toyota sure caused mad confusion with the whole naming schema after using roman numerals for 2010.
     
    #8 Paradox, May 8, 2013
  9. bedrock8x

    bedrock8x Senior Member

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    You should keep a camera ready in the car. When the pedal goes to the floor, hold it there and take a picture. Show it to the dealer as evidence and ask for repair.
    I suspect the brake accumulator pump fails to run when the car is not in Ready. It suppose to run by itself to keep brake pressure up at all times.
     
    #9 bedrock8x, May 8, 2013
  10. spiderman

    spiderman wretched

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    Something similar happened to me once. I was pulling up to a crosswalk at about 15 - 20 mph when I struck a sharp ridge (about 3-5" high) of ice just before the crosswalk (heated crosswalk). I was very gently braking and as soon as I hit it, the pedal sank all the way to the floor, lights on the dash lit up and there was a couple of beeps. I didn't think to lift up and reapply and ended up stopping within the crosswalk. The brakes were still applied though at the same light amount. Good thing there was nobody in it. Scared the crap out of me.

    I really can't attribute this to the switch over between regen and fiction braking. I have felt that before and certainly didn't get the lights and beeps with that happens. To me is seemed like a complete failure, though temporary of the system. I had the ABS update done right after that though. Haven't had it happen since.

    Certainly something to bring up with the dealer as others mentioned.
     
    #10 spiderman, May 8, 2013
  11. Andymon

    Andymon New Member

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    Take video of your brake pedal during start-up the next 10 times you start the car. I want to see this in action.
     
    #11 Andymon, May 10, 2013
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