Lexus LX 470 1998 Owner's Manual page 26

NOTICE
D Do not let the key case become bent as the key may fall out or
become bent also.
D The flat key is designed for emergency use only.
11L021-2
When using a key containing a transponder chip, observe the
following precautions:
D When starting the engine, do not use the key with a key ring
resting on the key grip and do not press the key ring against
the key grip. Otherwise the engine may not start, or may stop
soon after it starts.
11R055
D When starting the engine, do not use the key with other
transponder keys around (including keys of other vehicles)
and do not press other key plates against the key grip.
Otherwise the engine may not start, or may stop soon after it
starts. If this happens, remove the key once and then insert
it again after taking off other transponder keys (including
keys of other vehicles) from the ring or while gripping or
covering them with your hand to start the engine.
KEYS AND DOORS
9