Powertrain Control Module
WARNING: This page is about a different car, the 2005 Chevrolet Malibu. However, it is still accessible from the selected car via links, so may be relevant.
The powertrain control module (PCM) is the control center for the throttle actuator control (TAC) system. The PCM determines the drivers intent and then calculates the appropriate throttle response. The PCM achieves throttle positioning by providing a pulse width modulated voltage to the TAC motor.