Lexus GS300 1998 Owner's Manual page 85

GAUGES, METERS AND SERVICE REMINDER INDICATORS
4. Turn the ignition key to "ON".
The following service reminder indicators should come on.
or
The following service reminder indicators go off after a few
seconds.
or
72
The lights other than the slip indicator light may come on for
about 60 seconds after the engine is started. It is normal if they
go out after a while.
or