GMC Yukon Denalid Owner's Manual page 308

If there is no apparent damage, try a known
good CD.
Notice: If you add any label to a CD, insert
more than one CD into the slot at a time,
or attempt to play scratched or damaged CDs,
you could damage the CD player. When
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.
Do not add any label to a CD, it could get caught
in the CD 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 soft marker instead.
If an error appears on the display, see "CD
Messages" later in this section.
308
CD (Eject): Press and release the CD
Z
eject button to eject the CD-R that is currently
playing in the bottom slot. You will hear a
beep and Ejecting Disc will be displayed. Once
the disc is ejected, Remove Disc will appear
on display. The CD-R can be removed. If the CD-R
is not removed, after several seconds, the CD-R
will be automatically pulled back into the player.
If loading and reading of a CD cannot be
completed, such as unknown format, etc., and the
disc fails to eject, press and hold the DVD eject
button for more than five seconds to force the disc
to eject.
DVD (Eject): Press and release the DVD eject
Z
button to eject the CD-R that is currently playing in
the top slot. You will hear a beep and Ejecting Disc
will be displayed. Once the disc is ejected, Remove
Disc will appear on display. The CD-R can be
removed. If the CD-R is not removed, after several
seconds, the CD-R will be automatically pulled back
into the player. If loading and reading of a CD
cannot be completed, such as unknown format,
etc., and the disc fails to eject, press and hold the
DVD eject button for more than five seconds to
force the disc to eject.