Lexus RX 450h 2010 Owner's Manual, Quick Manual page 82

What to do if ...
If the hybrid system doesn't start
Make sure that the correct operating procedures have been followed.
Brake pedal
Steering wheel lock
If the hybrid system still does not start, see the Owner's Manual for more information or
contact your Lexus dealer.
81
Make sure that the brake pedal is firmly
depressed when attempting to start the hybrid
system.
Make sure that the steering wheel lock is
released.
To release it, press the "POWER" switch while
gently turning the wheel left or right.