WARNING: This page is about a different car, the 2005 Saturn Ion 3, 2005 Saturn Ion 2, and 2005 Saturn Ion 1. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: Power, Ground, MIL, and Serial Data Schematics
Courtesy of GENERAL MOTORS CORP.
Fig 2: Engine Data Sensors - 5-Volt and Low Reference Bussing Schematics
Courtesy of GENERAL MOTORS CORP.
Fig 3: Engine Data Sensors - Pressure, Temperature, and MAF/IAT Schematics
Courtesy of GENERAL MOTORS CORP.
Fig 4: Engine Data Sensors Schematics - HO2S
Courtesy of GENERAL MOTORS CORP.
Fig 5: Engine Data Sensors - APP and TAC Schematics