GMC 2011 Sierra Owner's Manual page 249

If a label is added to
a CD, or more than one CD is
inserted into the slot at a time,
or an attempt is made to play
scratched or damaged CDs, the
CD player could be damaged.
While using the CD player, use
only CDs in good condition
without any label, load one CD at
a time, and keep the CD player
and the loading slot free of
foreign materials, liquids, and
debris.
If an error displays, see CD
Messages later in this section.
Care of CDs and DVDs
If playing a CD-R or CD-RW, the
sound quality can be reduced due to
CD-R or CD-RW quality, the method
of recording, the quality of the music
that has been recorded, and the
way the CD-R or CD-RW has been
handled. Handle them carefully.
Store CD-Rs or CD-RWs in their
original cases or other protective
cases and away from direct sunlight
and dust. The CD or DVD player
scans the bottom surface of the
disc. If the surface of a disc is
damaged, such as cracked, broken,
or scratched, the disc does not play
properly or not at all. Do not touch
the bottom side of a disc while
handling it; this could damage the
surface. Pick up discs by grasping
the outer edges or the edge of the
hole and the outer edge.
I n f o r ma t i o n P r o v i d e d b y :
Infotainment System
If the surface of a disc is soiled,
clean it with a soft, lint free cloth or
dampen a clean, soft cloth in a mild,
neutral detergent solution mixed
with water. Make sure the wiping
process starts from the center to
the edge.
Audio Output
Only one audio source can be heard
through the speakers at one time.
An audio source is defined as DVD
slot, CD slot, XM, FM AM, front
auxiliary jack, USB port, or rear
auxiliary jack.
O
Press the button to turn the radio
on. The radio can be heard through
all of the vehicle speakers.
7-23