Conditions for Setting the DTC

WARNING: This page is about a different car, the 2019 GMC Savana 3500, 2019 GMC Savana 2500, 2019 Chevrolet Express 3500, and 2019 Chevrolet Express 2500. However, it is still accessible from the selected car via links, so may be relevant.

The local interconnect network bus circuit has an open/high resistance, short to ground, or a short to voltage.
The ignition voltage circuit of the RCM is open or shorted to ground.
The ground circuit of the RCM is open.