GMC 2009 Sierra - Manual (Page 223)

When a CD is inserted, the text label DVD or CD
symbol displays on the left side of the radio display.
As each new track starts to play, the track number
displays.
The CD player can play the smaller 3 inch (8 cm)
single CDs with an adapter ring. Full-size CDs and the
smaller CDs are loaded in the same manner.
Care of Your CDs
If playing a CD-R, 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-R(s) or CD-RW(s) 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 CD is damaged, such as cracked, broken,
or scratched, the CD does not play properly or not
at all. Do not touch the bottom side of a CD while
handling it; this could damage the surface. Pick up CDs
by grasping the outer edges or the edge of the hole
and the outer edge.
If the surface of a CD is soiled, take a soft, lint free
cloth or dampen a clean, soft cloth in a mild, neutral
detergent solution mixed with water, and clean it.
Make sure the wiping process starts from the center
to the edge.
Care of Your CD and DVD Player
Do not add any label to a CD, it could get caught in the
CD or DVD player. If a CD is recorded on a personal
computer and a description label is needed, try labeling
the top of the recorded CD with a marking pen.
The use of CD lens cleaners for CDs is not advised,
due to the risk of contaminating the lens of the CD optics
with lubricants internal to the CD and DVD player
mechanism.
Notice: 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.
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