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High frequency clicking by driver footwell

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by bulldog, Jul 27, 2006.

  1. bulldog

    bulldog Member

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    I searched, but wasn't able to find a topic containing my specific issue.

    We just got our Prius on Saturday, so I'm not sure of this sound is normal as it sure does have a lot of pumps, etc running at odd times.

    My concern is that when driving slow (less than 5MPH or so) and hitting the brake lightly there is a rapid clicking sound in the drive foot well area. It also happens sometimes when accelerating at low speeds by just touching the gas pedal. I sounds like relay chatter to me, which is not a good sign. Is this normal or is it an issue that needs to be addressed? If it is an issue what is the problem?

    Thanks
     
    #1 bulldog, Jul 27, 2006
  2. Betelgeuse

    Betelgeuse Active Member

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    <div class='quotetop'>QUOTE(bulldog @ Jul 27 2006, 03:39 AM) [snapback]293048[/snapback]</div>
    Sounds like the brake accumulator pump, to me. Here's a way to test it: bring the car to a stop and put it in park. Wait for the gas engine to shut down if it hasn't already. Pump the brake pedal a few (i.e. 4 or 5) times. You should hear that same sound.

    Here's the deal (as I understand it; I'm not an absolute expert on these things): the brake pressure in "normal" cars is powered off the engine. The difference with the Prius is that you want brake pressure all the time (i.e. not just when the ICE is on). So, there's an electric brake accumulator pump that makes that clicking sound. I actually often hear the clicking sound right after I turn off the car.

    P.S. The reason I know the answer to this question is that it scared me when I first got the car, too. :)
     
    #2 Betelgeuse, Jul 27, 2006
  3. bulldog

    bulldog Member

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    <div class='quotetop'>QUOTE(Betelgeuse @ Jul 27 2006, 05:20 AM) [snapback]293079[/snapback]</div>
    Thx, I will try that this evening. I have a new generation 4Runner as well. They aslo have the new electric brakebooster systems, but the sound is very different on those brake systems. Nevertheless I will check it out.
     
    #3 bulldog, Jul 27, 2006
  4. SomervillePrius

    SomervillePrius New Member

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    <div class='quotetop'>QUOTE(bulldog @ Jul 27 2006, 02:01 PM) [snapback]293297[/snapback]</div>
    I think it's normal break pump sounds you hear. Having the ICE of makes the noise that much louder as the car is so quiet. I know this sound freaked me out in the beginning as well. Note that it's not the same as a brakebooster system. This is a way to keep break pressure up even when you shut down the gas engine.
     
    #4 SomervillePrius, Jul 27, 2006
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