CD Player fix for "Check Disc" won't load - SINGLE
Basically, to make a long story short, I bought an '07 Colorado that came with an AM/FM radio only. Picked up an MP3 deck from eBay and flashed it to work with the truck (see other threads if you need more info about flashing the radio to work with your truck). All was working well except that the deck would not load any CD's. It would take it in, then spit it out saying "Check CD", and the whole time the motors would be either pulling in or pushing out the CD. Since this was not the original radio that came with the truck, I didn't want to take it back to the dealer and ask them to take care of it. Here goes how this problem was fixed:
First, remove the entire deck (how-to's can be found on other posts).
The good thing about the latest MP3 deck for these trucks is that when you look at the deck, you'll notice that there is a metal top plate that is only held in by tabs, and not any screws. Working carefully, you can bend the tabs around the plate to remove it. Set the large top plate aside, and peer into the inside of the CD deck.
Once looking down inside the unit, you'll notice a metal plate that covers the top of the actual CD drive (tray?). Remove the two screws and carefully lift up the metal plate on the inside top of the deck (should be pretty obvious, mine were marked with a blue pen from the factory). This plate had pieces of felt tape on my particular deck. Set this plate and screws aside.
Keep in mind that you should NOT be messing with the lower (black) CD spindle or lens assembly, only a top plate that's hinged. This plate should also be holding a plastic arm and a metal arm that move together and share a spring. You'll notice that the top of the CD drive (which contains the top spindle to hold the CD in place - the one on mine was a white piece of plastic) is held in by two tabs and a spring on the right edge of this top metal plate. You'll have to pivot this whole plate up while sliding it to the left to get it off the rear left tab. Once you've done that, work back to get the plate off of the right rear retaining tab. After that, carefully remove the spring from the right front of the plate (the spring should stay in its place even after being disconnected from the top plate, do not mess with any other springs.) If you lose a spring, they are usually easily recovered by shaking the unit upside down.
Now, with the top metal plate in your hand, look on the underside of it. Chances are that there is a rectangular piece of plastic that has worked itself loose. This piece is the plastic piece that is responsible for using the force of the CD being pushed in to lower the metal plate and secure the CD in the reader, which only THEN will the deck read your CD. I did it fairly quickly and hastily, but after a few minutes, You'll start to see how it all works. The CD is pushed in, which eventually hits a plastic piece connected to a plastic arm, which pushes a metal bar to push a toothed track (on the right rear corner of the CD deck) into a motor. This toothed track then slides a plastic arm on the deck forward, which makes the spring-held top metal plate drop, locking the CD into place for play. Anyway, the plastic piece that first makes contact with the CD (It is curved and has stops) fell out on my deck, getting in the way of loaded CD's and preventing the magic from happening. I was really disappointed with the quality of the build of the CD mechanism, it's acceptable for cheap toys, but not a automotive stereo system.
In short, if you're in a situation where you're out of warranty, etc., and have a CD deck that won't take in your CD's, it's worth a shot to get in there and make sure that something didn't fall loose. The top metal plate in the CD deck is relatively simple, and it's hard to break anything provided that you are patient and don't get too deep into the CD mechanism (two screws and 1-2 springs are all you should need to remove). I would have posted pictures, but I was really expecting the worst by the time I ripped out the deck in my truck. Incidentally, I forgot to re-install the metal plate that's held in by two screws (too excited to see the CD player actually working). I'll post pictures when I get around to taking the radio out again. Also, while I don't recommend it, this fix was done partially with the radio still plugged into the truck (to watch how it takes in CD's).
2008 Colorado Z85 Crew Cab I4
Flowmaster Delta 40, Pioneer FHP-8000BT
Had 2007 Colorado LS Ext. Cab 5 Speed I4
(0% financing sale got me to upgrade)