Circuit/System Description
WARNING: This page is about a different car, the 2013 Cadillac XTS. However, it is still accessible from the selected car via links, so may be relevant.
The devices connected to the chassis high speed GMLAN serial data circuits monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the devices when the ignition switch is in any position other than OFF. The chassis high speed GMLAN serial data bus uses terminating resistors that are in parallel with the chassis high speed GMLAN (+) and (-) circuits.