High-pitched electrical humming sound from the hood in Ready mode

Found the answer to my own question.
Page 153 Prius 2010 Owner's Manual.
Brake actuator - You may hear a sound in the engine compartment. This is not a mulfunction, if the driver's door is oponed with the hybrid system turned off.

 

My 2010 Prius is 4990K miles and just started doing the noise 3 days ago!! and is driving me crazy!!! I'm going to complain next Friday to the dealer when I get the first oil change, I will let you guys know my findings

The noise from the inside is like coming from the passengers door and is high pitched electrical with some crackings!!

This is an RECALL for sure coming down the pipe!! because the car never made this noise before since I bought it 6 months ago

 

My '04 Prius in Ready, engine off, made a softer noise of about similar charaterstics

My '07 FJ, Ign On but engine off, makes a VERY loud noise similar to yours. In the case of my FJ, it's the electric throttle body. That actually took me very much by surprise the first time I had the hood up, Ign On, motor off

 

That's quite a leap...

 

Well I'm in the dealer right now they informed me that the oil change is for 10.000 miles, I hope they change the software to reflect that service interval change, now for the noise they said IS NORMAL?? I knew was going to happen!! My noise has weeks they told me you didn't notice that before!!! they blamed the ABS pump as the noise source??

this is my first TOYOTA I have been always a HONDA guy but fell in love with the prius, I'm aware that TOYOTA is being known to avoid customer complains until someone really gets in trouble

My noise is actually getting worst, is a high pitch electrical noise and constant crackings you can hear actually cruising and in highway

I will continue to investigate and let you guys know

NOT HAPPY!!

 

I am having the same buzzing electrical noise. I get it when I'm on the highway going faster than 30-40 mph. It stops when I slow down below those speeds. The noise is a constant sound. I first though something loose was shaking but it was coming from under the hood and sounds like electric sounds statically buzzing.

Please let me know if you know how to fix or if anyone else does.

 

I hear a constant high-pitch humming from the ventillation fan all the time, but it was not unbearable "noise".

Try turning off the ventillation fan and see if this high-pitch humming constant noise is gone. If so, your fan motor may need fixing.

 

I actually have noticed that the car with all off only in ready "mode" the humming noise which is normal from the inverter is accompanied with the cracking noise !!! I haven't had time to record and post also need to go back to toyota dealer, hope other people have the same problem is very annoying I get people asking me what is that noise dude?

 

I believe what you are hearing is the electric power brake booster pump pre charging the system.

 

This is indeed a Gen III specific issue and a serious design flaw. Attached is a recording of the noise that I captured with my iPhone while sitting in the driver's seat. (use headphones when you listen to it).

Please voice your opinion directly to Toyota by calling 1-800-331-4331 and opening a case #. If enough people call, perhaps Toyota will do something about it. Let them know that you are dissatisfied the irritating high frequency pitches coming from your Gen III Prius.

Also here's is a frequency analysis chart taken from the attached recording that shows a spike in the high frequency range.

 

All my other vehicles make an "annoying" sound of the engine running. Get over it, it is just a little noise.

 

Sheesh, try driving a diesel instead, it makes a far more annoying noise.

 

If you think a diesel makes an annoying sound, try driving with your spouse!

:bolt:

 

I'm reasonably sure this is the throttle servo. It's a DC motor that's PWM driven that allows the ECU to open and close the engine throttle body. To test if this is the case, try manually moving the throttle body and listen for change.

Hint: it's below the air cleaner and before the intake manifold (mounted on the intake manifold)

The PWM noise is likely normal, but some throttle bodies are going to be noisier than others due to manufacturing and tolerance differences. If the noise is truly bothering you (for instance if you can hear it inside while driving), I'd get the stealer to replace it under warranty. The noise does not affect it's operation or reliability in most all cases.

 

Jesus!! what a shame I found part of the source of buzzing noise was on my prius!!

I bought from a friend an Ion Breeze car ionizer who has LED light for under the console in the 12V power outlet ! the thing started doing noises some times I took it off now and the only buzzing I have is coming from the inverter which is normal!!

For the inverter noise there is nothing we can do unless Toyota find a better way to seal that noise in the inverter chamber! I have been lucky I don't have the DVD navigation cracking noise but the front speakers are driving me bananas!!

I have been back twice to the dealer for the speakers rattle, they tightened them and then some days later starts rattling again!

Now I wonder if people with the PLASMA CLUSTER in Priuses level 4 or 5 have this problem too?

 

You beat me to it. I was going to say the only annoying noise in my car comes from the passenger seat!

 

Hey those "noisy" passengers provide your livihood? You're Grumpy! lol

 

lol I should have added that it only occurs when my gf is travelling with me!

 

Left side of the engine? That whine is definitely the ICE water pump. Easiest way to test is unplug the wiring harness to the pump, which is easy to reach after removing the air intake hose. Of course, only do it when the car is cold, and only run it for a minute or so to verify!