Faulty Throttle Actuator Control Motor
Throttle Actuator Control Motor harness is open or shorted
Throttle Actuator Control Motor circuit poor electrical connection
Engine Light ON (or Service Engine Soon Warning Light)
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. The TAC system uses the following circuits:
Motor control 1
Motor control 2
Two processors are also used to monitor the TAC system data. Both processors are located within the ECM. Both processors monitor each other’s data to verify that the indicated throttle position is correct.