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Is my brake unit going out?

Discussion in 'Gen 2 Prius Technical Discussion' started by tonybluegoat, May 13, 2019.

  1. tonybluegoat

    tonybluegoat Junior Member

    Joined:
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    Location:
    east texas
    Vehicle:
    2006 Prius
    Model:
    III
    I'm certain that I used to hear my brake unit pressurizing up when I got in my 06. Little buzz and hum. I'm not hearing that anymore. Haven't been for a while. Also about half a dozen times (no pattern that I can detect) I get in the car, put my foot on the brake pedal, start it up, then shift into reverse and it starts going backward with my foot on the pedal. Not too far, maybe 3-4 feet. It feels like there's no pressure. Then it straightens itself out. 20 times, no issues, then 1 time it sneaks back on me.

    About 375K miles on the car. Lots of wear and tear. I live on a dirt road so it gets rattled around a lot.

    Just curious. When I back into something I might get a little more than curious.

    Tony
     
    #1 tonybluegoat, May 13, 2019
  2. ChapmanF

    ChapmanF Senior Member

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    Location:
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    Vehicle:
    2010 Prius
    Model:
    IV
    The system that builds up the brake fluid pressure can wear out, but generally not without multiple trouble codes and (before it gets to symptoms like yours) an ear-piercing continuous high-pitched beep alarm.

    Have you had any warning lights or trouble codes, or asked anybody to cut the wires on an annoying high-pitched beeper?
     
    #2 ChapmanF, May 13, 2019
  3. tonybluegoat

    tonybluegoat Junior Member

    Joined:
    Jul 11, 2017
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    Location:
    east texas
    Vehicle:
    2006 Prius
    Model:
    III
    No, I haven't had any high pitch beeping sounds. I don't think I've had any new codes. I would have to look. I have a number of persistent codes that I just ignore. Cat Converter and hot water bottle. thank for replying
     
    #3 tonybluegoat, May 13, 2019
  4. Skibob

    Skibob Senior Member

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    I have had that high beep come on before but unfortunately I have almost no hearing in that range. I only heard it when I moved my head a certain way. I did notice the brake light comes on at the same time. The same light that’s on when the parking brake is set.
     
    #4 Skibob, May 14, 2019
  5. Skibob

    Skibob Senior Member

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    What do you read your codes with? The generic coda readers might not pick it up.
     
    #5 Skibob, May 14, 2019
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