Circuit/System Description
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2009 GMC Yukon XL, 2009 GMC Yukon, 2009 Chevrolet Tahoe, 2009 Chevrolet Suburban, and 2009 Chevrolet Avalanche. 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.