Conditions for Setting the DTC

WARNING: This page is about a different car, the 2010 GMC Sierra, 2010 GMC Cab & Chassis Sierra, 2010 Chevrolet Silverado, and 2010 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

The VIN embedded in the slow-down request does not match the VIN stored in the ECM.
The rolling code counter embedded in the slow-down request does not increment for ten consecutive messages.