Buzzing Sound From Underneath While Powered OFF

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by yyyiiikes, Jan 19, 2012.

  1. yyyiiikes

    yyyiiikes Junior Member

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    Location:
    Austin, TX
    Vehicle:
    2011 Prius
    Model:
    Three
    Scenario:
    My car had been sitting in the garage for over 5 hours after short drive this morning. I went into the garage ( without the FOB ) and heard a strange buzzing sound. After walking around I determined it was coming from underneath the rear of the prius. I opened a couple of doors and the hatch and the sound was definitely exterior not interior and continuous.

    I don't know how long this had been going on but it was continuous for at least four minutes. I thought the best thing to do would be to take the car for a short spin. I went inside the house to get the FOB and returned to the garage - the noise was still there? I approached the right rear bumper to get a better listen and it stopped suddenly. I guess the difference was the proximity of the FOB?

    Yes, I am a relatively new Prius owner but I am not bothered by unique sounds the Prius makes. But this was quite unexpected for a car that had been shutdown for so long. Also, I am in the garage quite a bit, back and forth and have never heard this before in about 3 months of ownership.

    Thoughts appreciated... Did a battery vent fan fail to shut off perhaps?

    In case it is relevant, the temperatures here in Texas today are very moderate - mid 60s.
     
  2. Paradox

    Paradox Prius Enthusiast / Moderator
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    It's in the manual, it is the sound of a pump performing a fuel evaporation leakage check.

     
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  3. yyyiiikes

    yyyiiikes Junior Member

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    Location:
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    2011 Prius
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    Three
    Excellent! That fits the description perfectly. Thank you.

    For the record, I have been reading the manual - but have not gotten all the way to the end. :)
     
  4. Paradox

    Paradox Prius Enthusiast / Moderator
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    Five
    Lol, no problem. Another question MANY post about and are not aware the car has is hill assist. When stopped, with the car in drive and foot on the brake, press down hard on the brake pedal and you'll hear a beep and a yellow light comes on the dash. That means hill start assist is activated and if on a hill the car will hold steady a few seconds while you transition from the brake to the gas pedal. You may have known about it but in case ya' didn't now ya' do. :)