Circuit Description
WARNING: This page is about a different car, the 2004 Pontiac Aztek and 2004 Buick Rendezvous. However, it is still accessible from the selected car via links, so may be relevant.
There are 2 different communication networks on this vehicle: The class 2 network and the GMLAN network. The class 2 serial data link, and the GMLAN High Speed serial data circuit link. Modules that need real time communications are attached to the high speed network. The engine control module (ECM) is the gateway between the networks. The purpose of the gateway is to transfer information from one network to another.