WARNING: This page is about a different car, the 2005 Cadillac CTS. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: Schematic - Module Power, Ground, Serial Data, and MIL
Courtesy of GENERAL MOTORS CORP.
Fig 2: Schematic - Engine Data Sensors - 5-Volt Reference
Courtesy of GENERAL MOTORS CORP.
Fig 3: Schematic - Engine Data Sensors - Low Reference
Courtesy of GENERAL MOTORS CORP.
Fig 4: Schematic - Engine Data Sensors - Pressure, Temperature, and MAF
Courtesy of GENERAL MOTORS CORP.
Fig 5: Schematic - Engine Data Sensors - Oxygen Sensors