rxtimes2

I have two distinct sounds. One when the headlights go off, and a louder one that lasts 5 or more seconds. I was told by a service advisor that the louder noise was coming from a brake system pump, but I don't think so. The noise is coming from the passenger side of the engine compartment seemingly below engine level.

Khides

I have discovered the source of my high pitched sound - it was related to the back seats. I only noticed when my daughter was in the back seat, playing with the seat at the same time that sound was on. We fixed it by just fully folding down the seats and then moving them back to position. Strange there's no light on the dash to tell you that's the problem.

GS350Miami

Mine has the same noise and it lasts for about 5 seconds after I turn her off. I have to be honest and say that I like it because it sounds like those spaceships in movies right after they land

rxtimes2

I am amazed that with all of the accumulated wisdom here, we still don’t know what this sound is.

PeeVee

I am surprised to see this thread and that nobody answered to it.
I could not find it but it has been answered before. I think it was in the "2016 RX 350 Excessive noise and vibration" thread.

The sound is the gaz vacuum pump testing for gaz leak. It is documented also in the user manual. It can decide to perform it from 5 min to one hour after the engine is stopped, and it can last up to 15 minutes (all those number are from the top of my head from what I remember reading in the manual)

SO this sound is very normal.

rxtimes2

Nope, that is not the sound we are hearing. The noise occurs immediately after shut down, and lasts for about 5 seconds. The “gaz” noise you are talking about happens in my vehicles about 5 hours after shutdown.

PeeVee

Are you talking about the automatic hand brake (electric motor)? It should engage as soon as you put on Park, not when the engine is turned off though...

rxtimes2

The car is in a garage (quiet). I put the car in Park (the parking brake sets) ,and I shut it down. As I exit the car I hear what sounds like a motor (perhaps a pump) running. It last for about 5 seconds. I have opened the hood and traced the sound to the passenger side of the engine compartment seemingly beneath the engine toward the firewall. The service manager told me to feel the rubber mounted pump (part of the brake system) which is located on the passenger side of the engine compartment, on top in the back, to see if I can tell if it is running and making the noise. I could not detect any vibration from this unit.