lets give this a try....you may nee to take it to the dealer if this dont work
Activating Theftlock IMPORTANT: With the ignition OFF, the THEFTLOCK indicator will flash.In order to activate the THEFTLOCK theft deterrent, perform the following steps:
Disabling the Theft-Deterrent Feature In order to disable the theft-deterrent feature, enter the user code as follows. Do not wait more than 15 seconds between steps.
Previous Track (PREV) Press SEEK down or PREV in order to search for the previous track.Audio is muted during SEEK.Random Playback (RDM) The random playback (RDM) feature allows the tracks on the compact disc play in random order rather than in sequential order.In order to stop the random playback feature, press RDM.During random playback, a RANDOM indicator appears in the display.Next Selection (NEXT) Press SEEK up or NEXT in order to search for the next selection.If you hold the SEEK up or NEXT push button or press the SEEK or NEXT push button more than once, the disc will advance further.Audio is muted during NEXT.Reverse (REV) Press and hold the REV push-button in order to return rapidly to a favorite passage. This is an audible search at a high rate of speed. Release REV in order to resume play at normal speed.Forward (FWD) Press and hold FWD in order to advance quickly within a track. This is an audible search at a high rate of speed. Release FWD in order to resume play at normal speed.Seek (SEEK)
Random (RANDOM) Press PSCAN in order to enter the random play mode. RANDOM will appear on the display. While in the random play mode, the tracks on the disc will play in a random order. If you press SEEK, PREV, or NEXT while in the random mode, the previous or next track will be scanned randomly. Press PSCAN again in order to turn OFF RANDOM and return to normal operation.Recall (RECALL) Press RECALL in order to see what track is playing. Press RECALL again within 5 seconds in order to view elapsed time. Elapsed time is displayed in minutes and seconds. Press RECALL again in order to return to the time of day. The track number appears when a new track starts to play.Tape/Auxiliary (TAPE/AUX) With a disc loaded in the player and the radio playing, press the TAPE/AUX once in order to play the compact disc. In order to return to playing the radio, press AM/FM. If both a cassette tape and the CD are loaded, press TAPE/AUX to switch between the tape and the compact disc.Ejecting a Compact Disc (EJECT) Press the EJECT button on the remote player in order to eject the compact disc. The disc will start at track 1 when the disc is reinserted.
Another Expert here:
The above procedure will NOT work.
Because the Radio is a Class 2 DATA Type Radio, you will need Dealer to connect Scan Tool & download Radio Info to Computer & they then get the UNLOCK Code from GM & Upload back into the Vehicle
There is No Customer Unlock Code
this did notwork radio still says locked when press 1 and 4 button nothing happens held them for 30 seconds
You will need to have the Dealer Unlock it
you will need to take it to the dealer