Just picked up my RX 350 yesterday. I was playing the radio and speaker settings in my garage today. I noticed a buzzing noise most likely from under the hood when I press the engine switch once or twice to Accessory or Ignition On mode. The engine is not running for this case (maybe it still has this noise when engine is running but couldn't hear). The noise goes up and down a little bit but just not goes away even after half hour. This is much more noticeable when all the front windows are open and in a quite garage environment. Does anyone notice this and can you explain a little bit if you know what it is? Hopefully it is normal but just want to confirm with you guys!

Jack

 

Could be fuel evaporation leakage check. It's something the 3RX does up to five hours after the vehicle is turned off. I haven't looked through the 4RX manual but that would be my best guess. The noise is normal.

 

Was reading the manual yesterday and yes, that is the noise it could make.

 

Thanks for your reply! I have stayed in the car for more than half an hour but still can hear the noise. As soon as I turned off the car completely (engine switch in OFF position), the noise goes away. Hopefully it is what you explained. Will confirm with dealer next time.

 

does that even when off. don't worry about it.

 

What he's describing doesn't sound like the evaporator check, which comes on a good number of hours after the car is shut down. Sound like its some solenoid or switch in the engine bay. More than likely normal. With the engine off, it's easier to hear all the electronic actuators and other parts moving.

 

has anyone else heard a buzzing noise from the rear wheels. Mine was specifically on the passenger side.

the noise happened when the car had been parked all day and was off. I noticed it when I stepped in the garage to throw out trash. The noise was not there right after I parked or maybe an hour or two after when I was in the garage for something else.

it almost sounds like a small motor actuator or something. heard twice in the last two days. It stopped when i started the car and then turned it off. It also stopped when I kicked the tire. Not sure if this was a coincidence.

 

chunktwo, the buzzing noise is probably from the RX doing the fuel evaporation leakage check. It can come on immediately after turning off the vehicle to several hours later. There's a short paragraph on page 8 of the owners manual regarding it.

 

There should be a "Sticky" across all forums. It gets asked all the time.

 

thanks to you both. My wife was “freaking” out about it. And that of course means I needed to freak out about it. I had done a quick search and got some threads about the air suspension on the GX.

thanks again alleviating my concern without flaming me to search first.

 

First of all - Happy New Years to all!

Tonight I was in my garage and I heard a constant vibrating, almost electrical sounding tone/rattle coming from the bottom rear of the RX. The engine had been off for about 5 hours. I started the RX and ran it for about 10 seconds and then shut it off. The noise stopped. Since I am not a big believer of coincidences, I am wondering if the following set this off: Earlier in the evening after I garaged the RX and shut off the engine, I poured 12 ounces of isopropyl dry gas into the tank (temps here have been below 10 degrees). I'm wondering if this set off anything related to the emissions system. Any thoughts on this would be appreciated.

 

It is the fuel evap check, or something like that. It's discussed in the manual, and all over CL lol.

https://www.clublexus.com/forums/gs-...is-normal.html

 

I wonder why lexus/Toyota didn't make this "check" quiet? I also think the mirrors moving and hatch/opening closing are too loud as well.

 

 

If it is a hizzing noise that you hear after engine is shut-off or not running, it is most likely, evaporation leakage check. There are few threads here that talked about it. It is completely normal. Check this extreme example of this sound(video):