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Cold Start - Brake Accumulator Pump

Discussion in 'Gen 2 Prius Main Forum' started by Marvinh, Apr 1, 2009.

  1. Marvinh

    Marvinh Marvin

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    I have a ratchety / pump noise when I start from a cold start and sometime when I switch from 'Park' to 'Drive'. But NOT when I just pump the brake pedal. The dealer correctly diagnosed the brake accumulator pump. (Note: this is NOT the same as the brake actuator pump 'barking' noise or the coolant transfer pump).

    My question is: How many have this noise on cold start?

    Thanks! Marvinh
     
    #1 Marvinh, Apr 1, 2009
  2. jayman

    jayman Senior Member

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    Mine has done that softly from day one, when I press on the brake pedal before pressing Start. Maybe have the dealer bleed the brakes?
     
    #2 jayman, Apr 1, 2009
  3. Mike Dimmick

    Mike Dimmick Active Member

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    No need, it's normal. The brake actuator is depressurized (a bit, not completely) by the car when you switch off, it has to rerun the pump to bring it back up to working pressure when you press the brake pedal.
     
    #3 Mike Dimmick, Apr 1, 2009
  4. Marvinh

    Marvinh Marvin

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    Yes. The dealer did bleed the brakes, but it made no difference. Marvinh
     
    #4 Marvinh, Apr 1, 2009
  5. Marvinh

    Marvinh Marvin

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    Mike, but is it supposed to make ratchety / pump noise that we hear on a cold start? Also if Toyota puts out a TSB, does that mean there could be a problem in the future?

    Thanks - Marvin
     
    #5 Marvinh, Apr 1, 2009
  6. jayman

    jayman Senior Member

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    Hmmm. Is there any way to compare it to another Prius? Although I just sold my '04, the boost pump was very quiet in that car, and it sounded about the same as the boost pump in my FJ

    However, I have heard Prius owners in parking lots power up, and theirs sounded like marbles rattling around in a tin coffee can
     
    #6 jayman, Apr 2, 2009
  7. galaxee

    galaxee mostly benevolent

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    sounds like the self-test. mine does it before i even start up if i take my time to get in the car.
     
    #7 galaxee, Apr 2, 2009
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