Since the vehicle is a 2008 it has to be an ls600h. listen carefully to the instructions to disable and you will see why it doesn’t matter if the key is in or out.
To disable the high energy system there are two procedures.
1. a. Confirm status ready indicator in inst. cluster. If ready indicator is illuminated ignition is on. Push power button once to disable ignition. DO NOT PUSH POWER BUTTON AGAIN!
b. Disconnect 12 volt battery cables starting with the negative 1st and 2nd the pos (battery located in trunk driver side behind interior quarter panel. KEEP SMART KEY 16 FEET AWAY FROM VEHICLE AS IT IS AN IMMOBILIZER KEY AND ONLY THE PRESENCE OF THE KEY ALLOWS THE MODULES TO COME ALIVE.
Procedure 2. If the smart key cant be 16 feet away do the same as above but remove IG#2 relay from the fuse box on passenger side engine compartment bay.
[b]NOTE: HIGH VOLTAGE SYSTEM WILL REMAIN POWERED ON FOR UP TO 10 MINUTES AFTER THE HIGH ENERGY POWER SYSTEM IS OFF/DISABLED.
Courtesy of hybrid hazards and of course me.[/b]