What is that mechanical whine noise in the front?

I'm pretty sure I know what the OP is hearing as my 2010 with ~850 miles does the same thing. I'll try to be exact. The sound is very similar in pitch and whine to a small jet engine when you hear it idling at low rpm when you are standing inside the terminal and it bounces off the terminal glass. It's no where near that loud but as to the pitch, it's right on. When I get in the vehicle in the morning after sitting all night, back out of the garage, and then drive 15-20 mph 2 blocks to the security gate, I can hear this whine being reflected back to me when I pass houses, cars, wood fences, etc. with the windows down. It's an exterior sound, as I do not hear it with the windows up. My wife clearly hears it as well. It does not vary with speed and it does not change with regen braking. I have also noticed it at other times long after the car is warmed up and been driven many miles. It's very high pitched. There are times when It does not make the sound but It seems to be there about 85% of the time and you will only hear it if you're going slow enough to hear it echo back to you off of some exterior object. Tapping the brakes soft or hard does not change it either. Also, A/C is off and It's only audible when moving but it's not speed specific or variable as to tone or pitch.

 

Excellent, thank you for the confirmation!

 

I've never noticed mine over 15 - 20 mpg but I suspect that's because the exterior environmental background noise outside the vehicle keeps me from hearing it at faster speeds.

 

Mark, you described the pitch and general sound of this whine to a tee! It reminded me of a small airplane engine whine, as well. However, I hear mine with the windows up, and only when decelerating. If I brake, it's a bit louder, but the whine is audible to me and my wife even when coasting to a stop (but not when gliding). I was reminded by pfreeus's post about the DVD that came with my car, which explains all the normal noises (and which I need to watch!). If not for PriusChat, I was going to drop by my Toyota service manager today and ask him if I had anything to worry about. :wave:

 

Not unless the dealership gives you one filled with coffee as part of the deal.

 

Since there are several "non-Detroit muscle car" noises to get used to, I wanted to be very specific in my description.

If you do mention it to the dealer, let us know what they say.