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What pump starts running under the hood when I open the door?

Discussion in 'Gen 3 Prius Technical Discussion' started by Ripley44224, Jun 9, 2010.

  1. Ripley44224

    Ripley44224 Member

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    III
    Just curious-- After several hours of not running, I open the driver door and hear a pump of some kind start up and run under the hood. Runs for a while then stops. How long seems to depend on how long the car has sat there, but about 30 seconds max. Anyone know what it is?
     
  2. phoenixgreg

    phoenixgreg Senior member

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    I think I read in another thread that it is the power brakes adding some pressure so you have instant braking just in case you run in EV mode briefly.
     
    1 person likes this.
  3. Paradox

    Paradox Prius Enthusiast / Moderator
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    Yes, it's the brake accumulator pump...
     
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  4. Ripley44224

    Ripley44224 Member

    Joined:
    Feb 26, 2010
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    Location:
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    Vehicle:
    2010 Prius
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    III
    Thanks, all!