Circuit/System Description
WARNING: This page is about a different car, the 2008 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
Modules connected to the low speed GMLAN serial data circuit monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the modules when the ignition switch is in any position other than OFF. The low speed GMLAN serial data circuit must be operational for the vehicle to start so the theft deterrent module (TDM) and body control module (BCM) can communicate. The low speed GMLAN serial data circuit uses JX200 and JX209 (splice pack combs) as a common connection between some modules and the DLC.