To be more precise, the car made a rather low-pitched, faint buzzing noise from the rear of the car (somewhere near the rear wheels) after the car has been sitting in the garage for a few hours. The buzzing continued for about a minute or two and went away on its own. This is the first time that I've heard the noise. Is that normal? What could it be since the noise was not coming from the front?

 

Might be heat causing metal or plastic expand or contract? I don't know~

 

could it be the air suspension?

 

I also think it might be related to the air suspension.

I noticed a similar noise, but for me it happened shortly after I had turned the car off.

I never noticed this sound on my 2006 GX, so I wonder if it has something to do with KDSS.

 

This is the gas tank fuel pump - circulates the fuel in order to facilitate fuel tank venting. O so I have been told by the dealer.

 

My GX doesn't have air suspension, so that can't be it. I was thinking it could be the gas tank fuel pump too, as gsobol suggested, but my car was in the garage - with the ignition off - for a few hours, and the pump was still moving? That's the "mystery" to this noise!

 

Look through the manual. I think it mentions somewhere that the fuel pump can activate an hour or two AFTER the vehicle was parked.

 

No, this is not in the manual.

 

OK, no wonder I couldn't find it.

But I tried googling more about fuel pump buzzing, and it seems normal that the fuel pump might activate a few hours after the ignition has been turned off. My previous car never had this buzzing, so I thought there was something strange going on this time.

 

We have also heard noises in our garage long after the car is cooled. Although it is nothing we can observe with any regularity or reliability, we have heard noises the next day when we are in the garage, but before we fire up the GX.

Page 20 of the owner's manual for the GX 460 has this reference, from which I quote:

https://secure.drivers.lexus.com/lex...html&locale=en

"Approximately five hours after the engine is turned off, you may hear sound coming from under the vehicle for several minutes. This is the sound of a fuel evaporation leakage check and, it does not indicate a malfunction."
Regards,

SaniDel

P.S. Off-topic, but related. Our 2006 RX 400h that we owned prior to and traded for the GX made so much noise in our garage that we nicknamed it the "electric calliope"!

 

Thank you for the reference, SaniDel, greatly appreciated it.