Throttle Control actuator(ACV) helps EEGR actuator in EGR control as controlling throttle flap position with the method of duty control. In EURO 3 diesel engine, precise EGR control is more difficult than in EURO 4 engine. Even though EGR actuator opens exhaust gas outlet fully, it is difficult for exhaust gas to be inhaled at intake manifold because intake air is already exist to be inhaled at there in EURO 3 engine. However in EURO 4 engine, controlling throttle flap position, it is possible to regulate the differential pressure between exhaust and intake air. With the control of the differential pressure, the amount of exhaust air to be recirculated is regulated. Besides, When turning engines OFF, Throttle control actuator cuts intake air to prevent dieselling.(In spite of turning engine OFF, engine does not stop and runs for a while due to rotating inertia of engine and fuel leakage at injector nozzle. )

P2101 is set When target throttle position is not match with actual throttle position in Throttle Actuator control logic.

Fig.1) Waveform of Throttle Actuator(ACV) at IDLE - Not Operation status.

Fig.2) Wavrform of Throttle Actuator(ACV) after Engine "OFF".