Strange cycling noise after brake release

Discussion in 'Gen 4 Prius Technical Discussion' started by Craig L, Apr 5, 2021.

  1. Craig L

    Craig L New Member

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    Vehicle:
    2016 Prius
    Model:
    Three Touring
    I have a 2016 3 Touring with approx 89k miles. Just noticed (heard) yesterday that when releasing the brake pedal at anytime (Doesn't matter if moving or in gear or neutral) I get an electrical cycling sound for about 3-5 seconds that sounds like it is coming from under the front left grill. Applying the brake pedal cancels it and then all I hear is the regular clicking in the back brakes. I've got about 300k miles driving Priuses and I've never heard this sound.
     
  2. bisco

    bisco cookie crumbler

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    can you post a video?

    does it sound like the pedestrian warning system?

    is it a buzzing sound like the brake accumulator?
     
  3. Craig L

    Craig L New Member

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    2016 Prius
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    Three Touring
  4. Craig L

    Craig L New Member

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    Location:
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    Vehicle:
    2016 Prius
    Model:
    Three Touring
    yeah sorry, had to figure out how to do the video.
    I just uploaded a video, hopefully it helps. I don't believe it to be part of the ped warning system because friends of ours that always comment on how quiet the car is were the first to notice the sound and alert me. I'm the original owner.

    Thanks
     
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  5. bisco

    bisco cookie crumbler

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    good job recording.
    yep, that''s the pedestrian warning system. not sure why you never heard it before.

    the volume is adjustable, maybe someone bumped it. you can find it in the o/m.
     
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  6. FuelMiser

    FuelMiser Senior Member

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    bisco nailed it. Sounds just like our '16 Three Touring. At the end of the recording, you actually hear the brake booster/accumulator pump just before the pedestrian warning comes on for the last time.
     
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