A mechanical noise of braking system

Discussion in 'Gen 1 Prius Plug-in 2012-2015' started by starrain, Jan 11, 2017.

  1. starrain

    starrain New Member

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    My 2013 prius plug-in had a mechanical noise after shutting off engine about 90 seconds. And sometimes I also could hear the same noise when powering on vehicle. The noise seems comes from the braking system.
    I uploaded a video about the noise. It happened at 1'38" of the video. Is there any prius owner having the same problem? I tested my friend's 2015 prius. The 2015 prius didn't have the noise.


    Thanks for response! I was not meaning the sound like when opening the door. I mean the sound happened at 1min and 38 seconds exactly.
    The sound also happened when on the vehicle. I also uploaded a video. I known prius had a sound when depressurizing. However, the sound of my vehicle was too loudly. I thought it still had some problem.

     
    #1 starrain, Jan 11, 2017
    Last edited: Jan 15, 2017
  2. QuantumFireball

    QuantumFireball Active Member

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    This is normal, don't worry about it. Can't say why it doesn't happen on the 2015, maybe it's specific to the Plug-in?
     
  3. bisco

    bisco cookie crumbler

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    welcome!
    are you talking about the loud clicking at the beginning, or the buzzing at the end?

    the buzzing is normal for all prius when you open the drivers door, and intermittently when driving and applying the brakes. that's refilling the brake booster.

    i've never heard the clicking on any of my 3 pri.
     
  4. QuantumFireball

    QuantumFireball Active Member

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    I think he's talking about click/buzzing near the end. It sounds similar to the servo noise when opening the door, but this is related to a short period after turning off the ignition and not the door. I notice the same whenever I hang around my car long enough after turning it off (e.g. when plugging it in). Sounds a bit flatulent from outside :oops:
     
  5. bisco

    bisco cookie crumbler

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    it's definitely activated by the door.

    and if he's not talking about the loud clicking noise, he should be.:p
     
  6. Pluggo

    Pluggo Senior Member

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    Listening at 1:32, that's the same electric motor noise I always hear after opening the driver's door and shortly after shutting down. I think it's the fuel tank pressurizing and, later, de-pressurizing. Keeps the old fuel fresh or something. I am still waiting to hear this one: "Approximately five hours after the hybrid system is turned off, you may hear sound coming from under the vehicle for several minutes. This is the sound of a fuel evaporation leakage check and, it does not indicate a malfunction."
     
  7. QuantumFireball

    QuantumFireball Active Member

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    I don't think it's the fuel tank, because I get the same noise and don't have a pressurised tank (it was not required outside of the US). It sounds like it's coming from the front of the car, I always assumed something to do with the brake servo.
     
  8. Pluggo

    Pluggo Senior Member

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    Well, yes, there is that slightly annoying servo sound that comes on for 3 or 4 seconds every time the car begins to come to a complete stop. It most noticeable while driving from stop sign to stop sign in neighborhoods.
     
  9. QuantumFireball

    QuantumFireball Active Member

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    Sorry, I'm aware of that but that's not what we're talking about here. It's some noise that happens some time after shutting down the car (90 seconds in the OP's case), and it's also not related to opening doors (I don't see the door light in starrain's video anyway, unless it's different on US cars).

    I might try and record this from my car if I get a chance. There's a whole page in the manual which is pretty much "this car makes lots of weird noises" and even though it's not very specific on this particular noise (it does mention the door opening brake servo stuff) I assumed it was normal.
     
  10. bisco

    bisco cookie crumbler

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    some clarification from the o/p might be helpful at this point.
     
  11. PRPrius

    PRPrius Active Member

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    That is a perfectly normal noise caused by the car as it depressurizes the Brake Pressure Accumulator. This is also the reason why the car has to activate the Brake Booster Pump when you open the driver's door. It has to pressurize the system when it thinks the car is about to be moved. I would assume that Toyota feels there is no point in leaving the accumulator pressurized when the car is park. It may extend the life of the accumulator by reducing the stress on the metal plunger within the accumulator.
     
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  12. starrain

    starrain New Member

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    Prius owners,
    I uploaded another video also had the mechanical noise. However, the second video was in the status of power starting. I thought the cylinder should not depressurize in the power starting status. Does yours prius/prius plug-in also had the loud sound when power starting?
     
  13. bisco

    bisco cookie crumbler

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    what do you mean by power starting?
     
  14. starrain

    starrain New Member

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    I mean starting the hybrid system not turning on the power mode.
     
  15. bisco

    bisco cookie crumbler

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    i see, well the drive modes have nothing to do with the with the brake accumulator. it operates the same way all the time.
     
  16. bisco

    bisco cookie crumbler

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    are you talking about the crunching noise?
     
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