Strange buzzing sound

[smc733]

Hi All,

Thanks to everyone's suggestions, I had a water pump replaced in my 2011 Corolla about a month ago, fortunately covered just under the wire by the powertrain warranty.

Today in my garage, however, I've noticed a sound I haven't heard before when the key is on ACC. I'm hoping someone may be able to tell me if this is a problem, and if so, what it is.

I've posted a video below of the sound with the hood popped (the best way to hear it). I don't think it is anything actually under the hood making the noise:
http://tinypic.com/r/1zl4sar/8

If I start the car, the sound goes away, as it does immediately when I turn off ACC. I know the fuel pump goes on when ACC is on, could that be it? Is this a bad sound (I have never heard this before, but I've only recently gotten a garage, otherwise I was always outside)?

If fuel levels have any relevance, I have almost exactly half a tank.

Thanks,
smc

 

[sxg6]

My 2009 Subaru Legacy has always made a buzzing sound when the key is in the ACC position, and I just hit 176k the other day. My buzzing sounds a little different, but I think it's probably just because of different car brands, and different parts used.

There's a guy on youtube called "briansmobile1" who has some pretty good car repair videos, I've watched a number of his Subaru videos. I can't remember exactly what he said, but in one of his Subaru videos he mentions that sound is caused by the drive by wire throttle system. This makes sense to me because my buzzing noise is the loudest at the throttle body. I just recorded an audio clip from my car. The video starts inside my car, then I get out and hold the camera over the throttle body.

http://youtu.be/wZg4mNZuaY4