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Home >> Hummer >> 2009 >> H3 Base, Standard >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Engine Controls And Fuel - 3.7L - Introduction >> Description and Operation >> Throttle Actuator Control (TAC) System Description >> Notes

Throttle Actuator Control (TAC) System Description: Notes

Fig 1: Throttle Actuator Control (TAC) System
GM1913732Courtesy of GENERAL MOTORS CORP.

The engine control module (ECM) is the control center for the throttle actuator control (TAC) system. The ECM determines the driver's intent based on input from the accelerator pedal position sensors, then calculates the appropriate throttle response based on the throttle position sensors. The ECM achieves throttle positioning by providing a pulse width modulated voltage to the throttle actuator motor. The throttle blade is spring loaded in both directions, and the default position is slightly open.