The TheftLock in the 2000+ radios operates differently than TheftLock in the older vehicles (which work using a simple code that you key in). 2k+ TheftLock checks the VIN number of the vehicle it is in, to verify that it is in the vehicle that it should be. If you put an OEM radio from another Bonneville in, the radio will be looking for a different VIN and thus will not operate. The only way too fix this is to have the radio re-programmed to look for the correct VIN number. This could be a costly reprogramming.