GMC 2014 Yukon/Yukon XL Owner's Manual page 202

The XM Satellite Radio antenna is
located on the roof of the vehicle.
Keep the antenna clear of
obstructions for clear radio
reception.
If the vehicle has a sunroof, the
performance of the XM system (if
equipped) may be affected if the
sunroof is open.
Do not add any label to a CD.
It could get caught in the CD. 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 player mechanism.
If an error displays, see CD Player
Messages later in this section.
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 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.