Envoy 4WD V8-5.3L VIN M (2005)
Engine Control Module: Description and Operation
Throttle Actuator Control (Tac) System
ENGINE CONTROL MODULE
The engine control module (ECM) is the control center for the throttle actuator control (TAC) system. The ECM determines the drivers intent and then
calculates the appropriate throttle response. The ECM achieves throttle positioning by providing a pulse width modulated voltage to the TAC motor.
