lili43

Car is off, open driver door, and it sounds like a humming sound under the engine for less than 10 seconds. It’s not a bad sound, just like something is priming? I also hear it a few seconds after I turn off the car and lock the doors.

This is not my first Lexus, but first LS.

What is it?

BB9

I believe it is a vacuum pump (or something of that nature) for the evap system. My LS does it as well.

DJWLDW

Are you sure it is not your hearing aids being overly sensitive? I thought my new P7 tires were really loud until I remembered I was now wearing hearing aids.

Dennis

Gerf

It's your brake actuator, always primes when you first open the door for about 10 seconds.

lili43

I can find no information on WHY this is happening. Do you? Ive had other Lexus’, and they didn’t do this. What makes the LS (or V8 versions?) do that?

Also, what makes it run after you turn off the car?

Gerf

This happens because you have electric brakes, it can run after the car is shut off because it's designed to do so to maintain pressure in the system in case of any loss.

dlbuckls10

I have 2010 LS 460L the bussing/humming sound is normal for a few seconds after pushing the stop button.