Buick 2007 Terraza Owner's Manual page 116

If the power sliding door(s) is open or in the
process of closing when you shift out of PARK (P),
a chime will sound. This is a warning that the
sliding door(s) is not completely closed. Also, the
Driver Information Center (DIC) will indicate if
the door is open. See DIC Warnings and
Messages on page 230. Stop the vehicle and
close the door.
CAUTION:
{
If you shift the transaxle out of PARK (P)
and accelerate before the power sliding
door latches closed, the door may reverse
to the open position. A child or others
could fall out of the vehicle and be
injured. Always make sure the power
sliding door is closed and latched before
you drive away.
116
If an object obstructs the power sliding door(s) while
it is closing, the door will automatically reverse to
the open position, provided it meets sufficient
resistance. Resistance must be as strong as the
force of the closing door, or stronger. The force of
the closing door increases significantly as the door
approaches the latched position.
The driver's side sliding door is designed to open
only a little if the fuel door is open. If this ever
happens, do not try to force the sliding door. When
the fuel filler door is closed, the driver's side
sliding door can be opened normally.