What could cause this hissing sound when the brake pedal is pressed?

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by SB6, Jun 26, 2020.

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  1. Tbkilb01

    Tbkilb01 Active Member

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    Try a different tool
    The autel Worked flawlessly
     
    #21 Tbkilb01, Mar 26, 2023
  2. douglasjre

    douglasjre Senior Member

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    Bad master cylinder, usually. What codes show on techstream?
     
    #22 douglasjre, Mar 27, 2023
  3. Tbkilb01

    Tbkilb01 Active Member

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    I had same problem On my 2011 ...206K
    Toyota messed up.. for sure... but ABS failures really happen to allot of makes and models And all expensive to get repaired.. this one is a DIY job...even if replaced booster pump too...
    2287F2FF-38DF-4F3A-926C-864D1F151A40.png
    mine had hissing sound with brake pedal released and stopped when pedal depressed. Hissing gradually got louder and stronger..Had a little fluid weeping at master cylinder connection... Then finally lit up DASH...

    BD3BA549-9994-4BAC-8842-68112957B547.jpeg But only thru a C1256 or at least that’s all AUTEL picked up ...

    I used the AUTEL tool to monitor LIVE DATA and BLEED SYSTEM ..flawlessly. It was a very simple job...once I decided to replace actuator. ..Toyota recommends replacing BOOSTER too but I didn’t want to condemn a good BOOSTER unit...The ABS works now like normal...Smooth replacement of a nonserviceable part. Steady pressure and minimal cycling of accumulator now.
     
    #23 Tbkilb01, Mar 27, 2023
    Last edited: Mar 27, 2023
    bisco likes this.
  4. SB6

    SB6 Member

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    I don't currently have any codes, but a few months ago when my hybrid battery voltage sensor had gone bad, I had C1202 and C1256. When I replaced my hybrid battery voltage sensor and cleared my codes, these two disappeared as well
     
    #24 SB6, Mar 30, 2023
  5. faisalak7

    faisalak7 Junior Member

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    Hi SB6, did you manage to fix the issue ?
     
    #25 faisalak7, Nov 28, 2023
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