Diagnostic Aids
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.
Use the DTC Descriptor list to determine the module which is not communicating. If there are multiple non-communicating modules in series on high speed GMLAN, choose the one closest to the data link connector (DLC) for this diagnostic.