Circuit Description
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.
Each time the ignition cycles from OFF to ON, the digital radio receiver receives VIN data over the class 2 communication circuit. If the VIN data in the digital radio receiver memory matches the VIN data it receives over the class 2 communication circuit, the digital radio receiver will operate normally.