WARNING: This page is about a different car, the 2008 Cadillac STS. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: Steering Angle and Acceleration Sensors Schematic
Courtesy of GENERAL MOTORS CORP.
Fig 2: Data Communication Schematic
Courtesy of GENERAL MOTORS CORP.
Fig 3: Active Front Steering Module and Actuator Schematic