Circuit/System Description (Object Alarm Module)
WARNING: This page is about a different car, the 2009 Cadillac DTS. However, it is still accessible from the selected car via links, so may be relevant.
When the ignition is turned ON, the object alarm module receives the vehicle identification number (VIN) from the body control module (BCM). The object alarm module will compare the VIN received to the VIN stored in memory.