Powertrain Control Module
WARNING: This page is about a different car, the 2004 GMC Envoy XUV, 2004 GMC Envoy XL, 2004 Chevrolet TrailBlazer, and 2004 Buick Rainier. However, it is still accessible from the selected car via links, so may be relevant.
The PCM determines the driver's intent and then calculates the appropriate throttle response. This information is sent to the TAC module through a dedicated serial data line.