Conditions for Setting the DTC
WARNING: This page is about a different car, the 2003 GMC Sierra, 2003 GMC Cab & Chassis Sierra, 2003 Chevrolet Silverado, and 2003 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
A node alive message has not been received from an unidentified module within the last 5 seconds after establishing class 2 serial data communication.