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"Chirp" on initial takeoff...

Discussion in 'Gen 4 Prius Care, Maintenance and Troubleshooting' started by RRxing, Aug 25, 2019.

  1. RRxing

    RRxing Senior Member

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    I've had my Three Touring for two years now, and I've heard this "chirp" from day one. It only does it when I first put it in drive and roll a few feet after first starting the car. The noise seems to be coming from the rear of the vehicle, but I can't determine if it's the left or right side. It's just a single "chirp." It's definitely a mechanical, not electrical or electronic, "chirp."

    Since I always use the parking brake I'm thinking it might be coming from there, but I was just wondering if anyone else is hearing the same thing or knows what's making the sound. The car is not throwing any codes (I checked yesterday with Carista) and I'm not having any other issues so I'm assuming it's normal. As I said, it's being doing it since day one.

    Thanks in advance.
     
    #1 RRxing, Aug 25, 2019
    Last edited: Aug 25, 2019
  2. The Professor

    The Professor Senior Member

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    I had the same question a while back. Took ages to figure out out.

    If it's the same thing as what I think it is, you will notice it happening when the car accelerates past 12mph for the first time after the car is first switched on. To me it sounded like a 1/4 second blast from a leaky high pressure air hose from somewhere near the driver's side rear brake.

    Anyway, turns out this is a self test the Prius does on the brakes to make sure they're not seized, to remove the rust from the brake system, and to check the automatic emergency braking system. The Prius is potentially more prone to seizing and greater rust build-up as the friction brakes are used less due to regenerative braking. So, when you hit 12mph for the first time after putting the car into Ready mode, the brakes are engaged gently for a fraction of a second, and that makes the "chirp".

    EDIT: Might be 12, 13 or 14mph.

    PREVIOUS THREAD: Very short screech noise when ICE starts. | PriusChat
     
    #2 The Professor, Aug 25, 2019
    Last edited: Aug 25, 2019
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  3. The Professor

    The Professor Senior Member

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    Found two more threads on this:
    Sound when accelerating the first time after a start | PriusChat
    and
    Squeak from Prius within the first few hundred feet | PriusChat

    The take away from this is:

     
    #3 The Professor, Aug 25, 2019
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  4. nuttydrew

    nuttydrew Junior Member

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    I as well hear a 'new to me' noise from my new 2019 Prius LE. Just got it this prior weekend, 8/24.
    I would call the noise a clank. It sounds dull and metallic. Rather inconsistently, it appears to make this sound one time both on acceleration and deceleration, at mostly low velocities, like stop and go traffic or stop signs.

    I have searched and searched this forum and will continue to investigate this sound. After reading the links above in this post I don't believe that to be the noise. However, description of such sounds are like art and open to interpretation. Chirp, whizz, whoosh, clank, bang, squeak, and or screech.

    Bought it with 210 miles and a bend in the driver door trim that is part of the weather gasket. The black metal trim is bent inwards, at the top and right most corner, with no damage to gasket or door. It doesn't sit flat and flush like the other side of the car. Dealership bent it back a bit and 'assured' me they will fix it and they will pay for it.

    This is my third Prius, each one keeps getting better... '08, '13, and now this '19.

    Good-day and thanks.
     
    #4 nuttydrew, Aug 28, 2019
  5. krmcg

    krmcg Lowered Blizzard Pearl Beauty

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    Onomatopoeia
    .
     
    #5 krmcg, Aug 28, 2019
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  6. The Professor

    The Professor Senior Member

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    Learnt a new word today. Thanks!
     
    #6 The Professor, Aug 28, 2019
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