Toyota Lexusc Owner's Handbook Manual page 34

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. Doing so may prevent
the engine from starting, or may cause the engine to
stop soon after it starts.
KEYS AND DOORS
15