My radio/ 6 disc CD player.

Car CD Players get dusty from road grime. Buy a CD Cleaning Disc and run it is a couple of times. The laser that reads the tracks is much lower power, and if it can't read the whole tracking system, it ejects the CD. The cleaning disc has little brushes that cleans the optic lenses.

https://www.google.com/search?q=CD+Cleaning+Disc

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There is an arm in/on the left side of the disc player. Most likely the spring inside it is broken. Leaving the arm in the pushed back position. Some times kids put coins in there also. This will cause things to happen, to include killing the radio and/or cd player.

Last radio I had that done the same problem I replaced the radio with an aftermarket radio and pulled my stock radio apart to get my cd out

Either the unit's motor is bad or the mechanical parts are dirty not allowing the unit to change CD's or load them.

Subject: Radio With Six Disc CD Changer Does Not Recognize Loaded CD And Displays An "INITIALIZING" Message, CD Will Not Play, CD Cannot Be Ejected, Or Disc Icon Does Not Illuminate (Reprogram Radio)
Models:
2005-2006 Chevrolet Avalanche, Suburban, Tahoe
2005-2007 Chevrolet Colorado, Express, Silverado Classic, TrailBlazer
2005-2006 GMC Yukon, Yukon XL
2005-2007 GMC Canyon, Envoy, Savana, Sierra Classic
2005-2006 HUMMER H2 with Six Disc CD Changer Equipped Audio System (RPO UC6)
Condition
Some customers may comment on any of the following conditions:
• The CD loaded in the radio will not play.
• The CD loaded in the radio will not eject.
• The disc icon on the radio will not illuminate.
• The radio displays an "INITIALIZING" message for approximately 30 seconds after vehicle start up.
Important: Do not attempt to play CDs with paper labels on them in this CD player. The labels may warp or wrinkle and jam the CD player mechanism. Refer to the Compact Disc Care and Cleaning procedure (Document ID# 1656123) in SI for more information.
Technicians are to reprogram the radio with new operating software using the following procedure:
1. If the radio has a CD(s)2008 General will be necessary to reset the radio and remove them
before the radio is reprogrammed. Remove and reinstall the radio fuse to reset the radio and then eject the CD(s). If cycling the power to the radio does not allow the CD(s) to be removed, the radio may have another failure that will not be corrected by the reprogramming procedure that follows. Refer to the Diagnostic Starting Point - Entertainment procedure in SI to begin your diagnosis of this failure to eject CDs concern before reprogramming the radio.
2. Reprogram the radio using the Service Programming System (SPS) with the latest software available on TIS2WEB. Refer to the SPS procedures and the Radio Programming and Set procedure in SI for more information. As always make sure your Tech 2® is updated with the latest software version.
3. Verify proper operation of the radio and make sure that all CDs can be ejected.

Hope helps (remember to rate this).

One thing have you tried to pull the CD out?

If it has a 6 cd cartridge, try this.Press and HOLD eject button, insert credit card under cartridge move left to right to locate micro switch which will release cartridge so then you can see if one of the discs has jammed.good luck.

Your car is in warranty; go back to the dealer.

dear friend- the error code means the lazer is not reading your cd,if it is a pirate cd it might be the problem,or the lens must be cleaned.

I had same problem with a 2005 Envoy in Jan '09. I took it to the ex-GM dealer. He said he'd try. The unit would only play using radio.
Mechanic took unit out of dash, and top off of unit. Ejected CD bu moving the eject mechanism. Replaced top and unit.
Works and plays cds. Cost $25.00 And i tipped the mechanic $10.00 for his knowledge.