Barely audible humming/whining sound when brake is pressed after startup

[gsolo]

It's not the A/C compressor (electric) is it? This car makes so many unfamiliar noises i've practically given up trying to identify them. I have a clunk from my tailgate every time i back up. Sounds like a bird hitting the window or something like that.

Me too i hear a clunk. It happens everytime the vehicle is left alone after driving. 3-4 minutes in the driveway and then "clunk".

 

[gsolo]

That is the sound from 5-7 mark, the sound I am trying to identify is from most clear from 14 to 28 second marks.

I started to notice this sound as well. Usually, after driving for a while (engine warm) and then going to a complete stop, but still in D. Sometimes the humming will go on for a while, at first i thought it was the AC. Its definitely humming while the engine is in auto-off

this is my first hybrid, all these noises make me crazy

 

[Bedawson]

Just noticed this on my 1958 after 14k miles. I can’t un-hear it now. Going to ask the dealer about at my next service

 

[b407driver]

That’s just the turbines in the jet engine slowing down nothing to worry about. Jk it sounds like either worn pads or the noise from the TSB.

Classic Reddit response, on several fronts.

 

[Zevgor]

I have also noticed this whine on the brakes this winter (first winter with it) and it’s been driving me nuts. It sounds like it may just be because it’s cold? It hasn’t warmed up past freezing for like 2 months so I haven’t got to check but I definitely know it wasn’t doing it before.

 

[Area 51]

That's the hamster in the wheel cage screaming when its squeezed to slow down.

 

[lar317]

Just noticed my brake humming is gone, I think this may be weather related ? It is now 55 degrees and I did not notice this sound last fall either

 

[Gopack77]

I have the same condition as well. Various degrees of noise depending on the the day and how hard brake is depressed. Ends when pedal released or a few seconds after car stops like a valve is closing. Sound is proportional to braking force applied. It seems to come from dash area. Dealership acknowledged it and replaced the booster pump. It dd not remedy the issue. This is not the booster pump sound. I've checked all lines on the firewall etc. for resonance but have not found anything yet.

 

[katekebo]

I have the same condition as well. Various degrees of noise depending on the the day and how hard brake is depressed. Ends when pedal released or a few seconds after car stops like a valve is closing. Sound is proportional to braking force applied. It seems to come from dash area. Dealership acknowledged it and replaced the booster pump. It dd not remedy the issue. This is not the booster pump sound. I've checked all lines on the firewall etc. for resonance but have not found anything yet.

There are two distinct sounds coming from the brake system, and both are perfectly normal and don't indicate a malfunction.

The first one is the booster compressor. It's the louder one, and you can hear it when you open the driver's door after leaving the car parked for some time. If you press the brake pedal repeatedly, you can hear it again and again, every 2-3 firm brake applications.

The second one is the ABS pump. Unlike other cars with vacuum booster, in which the ABS pump only runs when the ABS systems active, in the LC (and other hybrids), the ABS pumps runs every time the brake pedal is pressed. It's a much fainter noise that can only be heard when applying the brakes at low speed. As soon as the car comes to complete stop, the ABS pump stops and the sound ceases. The sound volume varies with the temperature - it's very noticeable below freezing temperatures, but almost imperceptible in warm weather.

If you have never owned a Toyota hybrid before, you will experience several noises that sound unfamiliar to somebody who has never owned a Toyota hybrid.