Communication Enable Circuit Description
WARNING: This page is about a different car, the 2012 Buick Verano. However, it is still accessible from the selected car via links, so may be relevant.
Control modules on GMLAN high speed type networks, excluding the Mid Speed GMLAN Bus and CAN Graphical Interface Bus, enable or disable communication based on the voltage level of this circuit. When the circuit voltage is high (around 12 V), communications are enabled. When the circuit is low, communications are disabled.
The CAN Graphical Interface Bus is similar but uses different voltage levels. See description above for the CAN Graphical Interface Bus.