Conditions for Setting the DTC

WARNING: This page is about a different car, the 2008 GMC Sierra, 2008 GMC Cab & Chassis Sierra, 2008 Chevrolet Silverado, and 2008 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

The 4-digit primary data key stored in the SDM does not match the 4 digits stored in the BCM.
The VIN stored in the BCM does not match that of the vehicle.