Powertrain Control Module
WARNING: This page is about a different car, the 2002 Oldsmobile Bravada, 2002 GMC Envoy XL, 2002 GMC Envoy, and 2002 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.
To program the Powertrain Control Module (PCM), see POWERTRAIN CONTROL MODULE under PROGRAMMING in SELF-DIAGNOSTICS article in FAULT ISOLATION in ENGINE PERFORMANCE.