Originally Posted by jzheng

Got car back yesterday. Apparently, the issue had been fixed. Lexus South Pointe (Edmonton, Alberta) checked the area I mentioned above discussion thread and did following:
CAUSE: poor fit of hv cable to firewall
CORRECTION: insulated high voltage orange wire on firewall. removed clip and applied felt to secure cable properly

I have driven the car a couples of times for total about 1 hour since yesterday afternoon and confirmed that the noise is gone. Current the temperature is around -20 c

hope it helps others