Digital Radio Receiver
WARNING: This page is about a different car, the 2007 Cadillac XLR. However, it is still accessible from the selected car via links, so may be relevant.
The digital radio receiver utilizes class 2 serial data to determine if it is in the appropriate vehicle. Each time the digital radio receiver receives the "run" power mode message, it compares the VIN information received from the BCM on the class 2 serial data circuit. If a mis-match occurs, the radio display will indicate to the user the digital radio receiver is locked. This will occur if a digital radio receiver is installed from another vehicle. The digital radio receiver cannot be unlocked, it must be replaced.