Lexus GS300 1998 Owner's Manual page 118

Jam protection function
During closing operation, the moon roof stops and is open if
something gets caught into the roof opening.
If an impact is given to the moon roof, this function may work
without anything caught.
CAUTION
D Never try jamming any part of your body to make the jam
protection function work intentionally.
D The jam protection function may not work when something
gets caught just before the moon roof fully closed.
EXTERIOR EQUIPMENT
105