WARNING: This page is about a different car, the 2003 Oldsmobile Aurora. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: Diagnostic System Check Drivers Door Module (DDM)
Courtesy of GENERAL MOTORS CORP.
Fig 2: Diagnostic System Check Powertrain Control Module - 3.5L
Courtesy of GENERAL MOTORS CORP.
Fig 3: Diagnostic System Check Powertrain Control Module - 4.0L
Courtesy of GENERAL MOTORS CORP.
Fig 4: Diagnostic System Check Rear Integration Module
Courtesy of GENERAL MOTORS CORP.
Fig 5: Diagnostic System Check Theft Deterrent Control Module