Need some explanation for these 2 sounds

Discussion in 'Gen 1 Prius Plug-in 2012-2015' started by Eric Vasaio, Jul 17, 2019.

  1. Eric Vasaio

    Eric Vasaio New Member

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    So I've got this 2013 PiP 2 month ago. I always hear these 2 sounds from this suppose to be very quiet car. I tends to think they're just normal sounds but...

    First, humming electric motor sound. Especially under low speed and gentle brakes, I can hear this bee humming sound relatively loud. If you have an old style not well lubricated electric fan in summer time, that's the sound.

    And then, every time, about 1 minute after I shut the car off, there's always a clunk sound from front of the car, maybe from under hood, or maybe from brakes which is really hard to tell. As if two metal pieces get engaged or disengaged.

    Are they normal Prius sounds? thanks for any input.
     
  2. Tideland Prius

    Tideland Prius Moderator of the North
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    The first is probably the Vehicle Pedestrian Notification System. It cuts out over 10mph or so.

    Not sure about the second.
     
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  3. ChapmanF

    ChapmanF Senior Member

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    Self-test of brake system, couple minutes after power off, every time. If you listen carefully, it's more than just "clunk", but more like "clunk ... clickity squish ... squish clunk".

    Utterly normal.

    Sometimes, it will need to repressurize during the test, so you'll hear the brake pump too ("whirrrrRRPclunk"). Not every time. Depends on what the accumulator pressure happens to be when the test starts. Don't be concerned because you do or don't hear it every time.

    If the car detects any problem, it'll tell you. That's why it self-tests. No news is good news. :)
     
    #3 ChapmanF, Jul 17, 2019
    Last edited: Jul 17, 2019
  4. cnc97

    cnc97 Senior Member

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    I’ve had my Prius 18 months now. I’ve heard just about every noise the car can make. However, some of my family members are still surprised when it starts itself or pressurizes the brakes jaut sitting in the driveway. They think it’s haunted. I tell them the car is just smarter then all of us and is getting ready to leave.
     
  5. bisco

    bisco cookie crumbler

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    you're car starts itself?:eek:
     
  6. ChapmanF

    ChapmanF Senior Member

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    I am Car Starts Itself. There's not room for two of us.
     
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  7. cnc97

    cnc97 Senior Member

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    When parked in “Ready” mode and the ICE restarts. LoL.
     
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  8. 4est

    4est Active Member

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    The first noise is the braking system building vacuum once in a while
     
  9. ChapmanF

    ChapmanF Senior Member

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    ... except that there is no use of vacuum anywhere in the braking system. There is a pump that puts brake fluid into a high-pressure accumulator though.
     
  10. Eric Vasaio

    Eric Vasaio New Member

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    Thanks, I found a video on YouTube, exactly this sound. Link of the video:


    What a relief. Thanks again.
     
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  11. Tideland Prius

    Tideland Prius Moderator of the North
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    From our very own PC member @F8L
     
  12. QuantumFireball

    QuantumFireball Active Member

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    In general: The Prius makes weird noises. You'll get used to it :)
     
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