Bah! - I apparently had picked up a nail that deflated my driver's front tire totally overnight in my garage.
I didn't figure out what the odd noise was until I had travelled 3 block in my neighborhood. The tire monitor system NEVER CAME ON!
As a result - it cost me $$$ for a new tire from the dealer, and a lecture on how the tire monitor system recalibrates on starting.
Thanks for nothing LEXUS!!!