Radio code (by 2 users)

Found this on another site.

General Motors coded THEFTLOCK® radios have a backup unlocking code that can be accessed by a General Motors dealer or a Delco® radio repair center if the owner programmed security code is not available. Honda, Acura and Audi anti-theft radios are examples that will require radio removal to access the radio serial number that a dealer needs to obtain the factory security code. Sometimes the original dealer for a vehicle may keep records of the radio security code for factory-coded radios.

Sounds like you may have to remove the stereo so you can see the code on the back.

Then I would take it to a local dealer and prove its yours and give them the serial number.

They should be able to decipher it for you.