md1twal3
I'm not a GM Tech, but I am a service engineer at GM.
Is this a remote CD unit? If it is it could be a communication error between the CD unit and the head main unit.
If the CD player is part of the head unit then all you can do is remove the unit and try to clean the lens with a qtip and lens cleaner. If this does not work then the unit will need to be sent to a radio repair shop.
GM does not recommend the use of CD lens cleaner discs. The risk of contaminating the lens of the CD optics with lubricants internal to the CD mechanism.
Sorry for the bad news,
I have a 99 STS the remote CD changer works good, but the one disc player in the head unit gives me a CD error. Somthing happens internal to the unit that causes a no disc read condition.