The ETC(Electronic Throttle Control) system which is composed of throttle body, the TPS(Throttle Position Sensor) 1&2 and the APS(Accelerator Position Sensor) 1&2 controls the mass of airflow by driver's intention. The throttle valve opening is controlled by throttle motor which is controlled by the ECM. the TPS is a variable resistance and its value is cahnged by open angle of throttle valve.