Cadillac 2005 STS Manual page 120

Lock/Unlock
This feature allows you to change the automatic door
locking and unlocking and the keyless access transmitter
locking and unlocking.
5-6
The following choices are available:
Automatic Door Unlock
If you turn this feature on, you may choose one of the
following options:
DRIVER unlock at OFF: This feature allows the
driver's door to automatically unlock when the ignition is
turned off. When this feature is turned on, the button
will appear highlighted next to the feature name.
ALL doors unlock at OFF: This feature allows all of
the doors to automatically unlock when ignition is turned
off. When this feature is turned on, the button will
appear highlighted next to the feature name.
DRIVER unlock in PARK: This feature allows the
driver's door to automatically unlock when the
transmission is shifted into PARK (P). When this feature
is turned on, the button will appear highlighted next
to the feature name.
ALL doors unlock in PARK: This feature allows all
doors to automatically unlock when the transmission is
shifted into PARK (P). When this feature is turned on, the
button will appear highlighted next to the feature name.