Throttle Actuator Control
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The Throttle Actuator Control (TAC) system uses vehicle electronics and components to calculate and control the position of the throttle plate. In order to decrease idle speed, the TAC system closes the throttle plate reducing air flow into the engine. In order to increase idle speed, the TAC system opens the throttle plate allowing more air flow into the engine. If actual idle RPM does not match the desired idle RPM within a calibrated time, a DTC will set.
The TAC system components include the Accelerator Pedal Position (APP) sensor, throttle body assembly, throttle actuator control module and PCM. See Figure and Figure .