Slight but annoying whine noise when operating brake pedal

These sort of noises are pretty much normal. The Prius doesn't use conventional hydraulic brakes like the cars most of us grew up driving.

As for high-pitched noises, certain people are capable of detecting higher-pitch frequencies than others, much like some of us can tell the difference between a 60hz refresh rate and a 75hz rate on a TV monitor. The hybrid drivetrain in these cars generates noises very much unlike the noise we're used to from conventional gasoline and diesel engines.

 

I hear mine just like OP. it's a certain amount of pressure on brake pedal whether in motion or stand still, on or off. You're right it's piercing, which is kinda hard to ignore even though its pretty faint. I'm 90% sure it's the inverter or something normal, but I've never noticed it in my Two, and I definitely noticed it right away in the Three. My only logical explanation is that the noise may have been on the Two, but just not as sensitive.

 

So I listened closely this morning and all I heard was the brake pump pumping up the brake fluid pressure. I didn’t hear the inverter till I started the car. This doesn’t necessarily mean anything it just means I didn’t hear any whining sounds until the car was in full operation. The 2013 could have a slightly different sequence to the 2012 or you are able to hear something I can’t. I highly doubt there is anything wrong with the car, but you can always have the service department check it out. The Prius makes a lot of different sounds to a regular gas only vehicle. If the sound is really objectionable to you, they make sound deadening material that can be placed around the source, as long as it doesn’t interfere with cooling, which can help. Do a search here on PC, there are several threads on this matting and it can be quite effective. Good luck.

 

Thanks Reedja42, I'm gonna give it a bit more and see how I acclimate to it. I'd say about 10-20% of my driving is with the radio off, so if it just gets too distracting, I'll take it to the dealer. I only have 700 miles on the odometer, so I got some time left.

 

Lets hope it's not the onset of this: The $3000 Brake Job | PriusChat

 

Yikes, Ok I'm definitely gonna take it in just to be on the safe side and have it on record.

 

The good news is you are under warranty and the car is brand new. It certainly wouldn’t hurt to have the service center take a look at things just to have it on record; then make sure you keep up the maintenance on the car and you should be fine. Remember there are now 5,000,000 Prii on the road and only a tiny fraction ever have trouble like that.

 

Yup, I just set up an appointment with the service dept. this coming monday afternoon. Will update with any further news. Wish me luck!

 

I have the same noise in my 2012 III, always thought it was something to do with the breaking and never thought it wasnt suppose to do it since i bought the car with less than a couple miles on it

 

It most likely is normal functioning. But I'm just gonna have em diagnose it just to be double sure and make sure there's no doubts while I'm still under warranty. At the same time, I wouldn't just take a car to the dealer for any little rattle or squeak. This sound is definitely noticeable, but may be ignored by non-prius drivers from being drowned by the other hybrid noises. Only reason I was able to distinguish it is because I've never heard it in my Two.

 

Report back what they say. I hear the same high pitch noise when I brake. This car has so many rattles, creaks, whistles and other mystery noises I can't describe, I just assume everything is normal.

 

A38A4480-FDB7-4EFD-9D38-CCFF939351AA-9872-00000546FDC27AFF.mp4 Video by p00kienrayray | Photobucket

Here's a vid I recorded of me slightly stepping on the brake while car is off. Im not sure if its recognizable in the vid or just too faint. If you can recognize it, please lemme know if this is normal and im just making something out of nothing. The faint sound you hear is the high pitch I'm talking about and it's actually more noticeable when car is in motion. One thing I realized today while driving home is that the sound can be heard while my foot is on the gas while car is in motion as well. So I'm kinda stumped.

It almost sounds like its some kind of electronic frequency coming from the speakers but I suspect it's from the bottom of steering column. Is this how the inverter sounds?

 

lol I will. All those rattles, creaks, and whistles are normal. The 2012s and up even has that proximity notification UFO-hovering sound on top of that. Only this high pitch sound that I'm not 100% sure of.

 

You guys are the people who drive OEM technicians insane Hybrids make weird noises. You have inverters, electric water pumps, electric motors, brake accumulators, shit-tons of relays, battery fans, electric steering motors and oh so much more... They're going to make odd noises even when functioning reliably for 100,000+miles. It's okay. Don't panic! No worries, I promise!

In fact.. go drive a 100% stock, mint condition car from 1991. Maybe even 1981! Your Prius won't seem anywhere near as noisy or awful as you might think it is! It's all a matter of perspective. Automobiles are mobile electro-mechanical wonders of mankind's own design. 100% silent is not natural or realistic

 

Im not panicking. More curious and distracted by the sound. I dont mind the rattles and other noise, i think some of its cool. But this piercing sound is borderline irritating. I believe it's most likely nothing problematic. I just want clarification, which to be honest, I'm not entirely sure even taking it to a Toyota tech would give. And if its something they or I can't fix, then I'll just leave the radio on and hope I grow accustomed to it. Thanks for your input. It is indeed helpful.

 

Also out of curiosity, since the general consensus suspects regen braking, does easing up on gas pedal activate regen braking? Would explain why I hear the sound with pressure on gas pedal as well.

 

If you're talking about the noise 10 seconds in,it's faint, but it sounds like the brake accumulator pumping up. It can come on at any time the system needs the reserve topped off, and that can even happen before the ready light is on. Normal.

 

Actually the noise is heard as soon as the video starts. It doesn't sound like a pump sound if that's what u were referring to.

 

The really high pitch sound that starts at the beginning is probably the inverter. You can pop the hood and put your ear by it to confirm.

 

Sounds like inverter whine to me; never heard it when the car was off before, but it sounds just like my inverter does. Maybe the 2013 switches it on when you touch the brake pedal. I think you're fine, I wouldn't worry about it.