High pitched sound normal?

I'm taking mine in to the dealer for my 5k miles checkup, will have them check the sound as well. Mine it louder with the ICE running, not sure if it's normal since it started after ~1k miles. Will let you know what the dealer says soon.

 

+1)

Exactly right, my last hearing test gave me the hearing of a 20 year old, and yes I hear it, and it is normal. If it bothers you too much you could try adding some sound deadening material to the car to reduce it.

I should add that many if not most people can't hear it, because the frequency is so high.

 

ZEEEEEEEEEEEEEEEEEEEEEEEEEEEEEE.

 

Hi All, I'm electrical engineer (even though I don't work as one right now). I will try to convey my understanding of this issue.

I can think of several possible sources of buzzing:

1) Invertor cooling pump (runs all the time when car is in ready). Kind of low - frequency hum.
2) Invertor (HV to 12V DC/DC convertor) (runs all the time when car is in ready to supply 12V)
3) Air Conditioning motor (in my car gives more like low-pitch hum or vibration)
4) Motor-Generator/Invertor MG drive (this one will only apply when moving, and the pitch will change as you release/push gas/go regeneration braking)
5) Battery cooling fan (at the back, only would run when battery is hot)
6) Engine water pump (on G3 only, and I have not heard any noises from it yet)

The principal reason for all these buzzing sounds is the presence of alternating current in circuits. Magnetic forces that appear as a result will try to move conductors/wiring back and forth. If these conductors have any play, they will vibrate and make sounds.

Another issue to consider here is that different people have different frequency threshold of their hearing. I can hear sine wave up to ~ 17 kHz, some people can hear up to 20 kHz, and some can not even hear 16 kHz. Its all individual. So mechanic at Toyota you complain to can be hearing nothing while you can.

Thanks,
- Alex (2005 G2 and 2010 G3 )

 

Correct; I can hear around 17KHz as well.

 

I recently bought a used 2006 and noticed the sound immediately after driving on a smooth, flat freeway. Mine is audible between 50-70 MPH and only when pressing on the gas petal, though i can just barely rest my foot on the petal for it to kick in. I'm a sound engineer and its driving me absolutely crazy. Is this as far as the conversation goes?...we should just live with it? I can't believe how common this issue is w/o toyota formally documenting it.

any info on how to further pursue this issue would be appreciated.

 

I spent some time listening to the sound and I’m sure it is the motor/generators. The problem is that this sound is at a fairly low level, so no one is in any danger of hearing loss or anything like that; thus for those who can hear the sound, it is only an irritant. Most people these days have cooked their ears with their ear buds and can’t hear it anyway, so Toyota is not going to make the Prius heavier, with sound dampening material for the few of us who can hear it. As a former broadcast engineer, now AV tech, I realize that for some it will be annoying, but honestly, though I can hear it, I don’t find it that much of an issue; but when the guy pulls up next to me with his 2,000 watt sub-woofer blaring; now that’s annoying! If it really bothers you, a search of the PC forum will turn up a recommendation for sound absorption material that can be installed under the interior carpet. This may reduce the level and the irritation for you. I do find it odd that you hear it between 50-70 mph. At that speed mine is totally drowned out by the road noise. For me it is most noticeable when driving slowly through parking lots, especially when on electric power only. Are you sure you aren’t hearing some kind of wind whistling on some part of the car?

 

It is annoying and is not unique to the Prius. A couple years back I had a Prius Gen II and then an Edsel HS250h and it was quite pronounced in that car too. I'm back in the hybrid group but with the ES300h. Finally, no more high pitched whining. Well, with the windows up I hear nothing. Windows down, slight but not as loud as I recall.

 

The noises don't bother me, I just like to know what they are. The other day, I was adding washer fluid and I heard a sound. It was on the passenger side of the engine compartment and sounded like it was coming from behind the engine. The car was in ready mode and HVAC was off.

 

I just purchased a 2015 Prius 2 with 12k miles. I hear the same high pitched sound. Annoying.

 

congrats and welcome! wait a few years, pretty much all the sounds go away...

 

My Prius has the same high pitched sound too. I love the high pitch sound. It sounds high tech and futuristic.

I heard it only during Regen or Ev drive though.

 

When you open the door of a Prius, a pump pressurizes the power brake system. In a conventional car, engine vacuum does this, but when you start a Prius, there may be no engine turning.

Also, when the engine is hot, a pump can turn on to pump cooling fluid over the power inverter.

 

just came across this old thread and I know exactly what this high pitch noise is, let me post the solution here just in case somebody wants to know how to fix it in the future.

basically I have high pitch noise on two of my Prius (I have total of 4), this high pitch noise can only be heard by sensitive ear and mostly children around age of 10, this noise is OK for some people, but very annoying and sometime cause headache for others. The root cause is the stereo head unit, most likely due to faulty component that fail to isolate the high frequency interference from the inverter, the solution is to replace the head unit with either aftermarket or factory stereo head unit, that solve the problem on both my 2006 and 2010 Prius.

 

does the h/u have to be on to hear the noise?

 

how long ago did you have the edsel?

 

the h/u doesn't have to be on to hear the noise, apparently the signal travel through the cable go all the way to speakers to give you a surrounded high-pitch experience.

 

wow, that's incredible. and good news for those stricken with the problem.

 

Thank you for this post! I have that sound and I was starting to research this. I noticed two things: 1) the high pitch sound and 2) when I turn on the car, if I put my ears close to the speakers there is a little static noise - is this also related?

Is the radio head unit the whole radio/screen assembly - this part that this mechanic takes out? Eng is is not my mother tongue and I wanna make sure I understand this technical bit

 

yes, that is the h/u