WARNING: This page is about a different car, the 2004 Cadillac CTS. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: Power, Ground, Serial Data, DIC and Indicator Schematic
Courtesy of GENERAL MOTORS CORP.
Fig 2: Engine Data Sensors Schematic - 5 Volt and Low Reference Buses
Courtesy of GENERAL MOTORS CORP.
Fig 3: Engine Data Sensors Schematic - ECT, MAF and IAT Sensors