Hi... for the first time ever, after owning my 2007 GS350 for about 10 years, I was alerted by a two beat tone while driving. This happened twice in the past 2 days, and I can't replicate it. The tone gave me the same impression you might get when you connect a USB device to a PC and it registers a connection. This sound occurred while driving and not messing with any devices.

Any ideas about what this might be?

 

Mark levingston stereo? if so maybe the amp is starting to go bad