Mercedes-Benz S 350 Owner's Manual page 280

Controls
Key positions
Removing the KEYLESS GO button
You can pull the KEYLESS GO button out of
the ignition lock and start the vehicle using
a key in the conventional way.
1 KEYLESS GO button
2 Ignition lock
i
When you change back from using the key to
using the KEYLESS GO function, the system re-
quires 2 seconds recognition time before you
will be able to use the KEYLESS GO button as
normal.
i
It is not necessary to remove the KEYLESS
GO button from the ignition lock when you leave
the vehicle.
258