Buzzing/electrical sound from transmission area

4runner SR5, 2019, 63k.
Recently I noticed an electrical buzzing sound coming from underneath the the truck, around transmission area.
It’s constant while truck is ON, it doesn’t change when going from N to D.
No slipping or any transmission problem. Any idea what could this be?

 

Probably a loose heat shield but no way to tell until you get under there.

 

Could it be evap system ?

 

Kind of like a humming noise? That is the evap system. Totally normal. It does it while the vehicle is parked and off as well.

 

Update. I spoke with a Toyota mechanic. He said it is completely normal to have that buzzing/hummung sound.