SCV valve( SUCTION CONTROL VALVE) is an inverse proportional solenoid proportional valve controlled by ECU, ECU receives engine speed, water temperature, common rail pressure, suction pressure and other signals, the SCV valve export command current, control the Angle of the SCV valve, in order to control the diesel flow into the oil pump, adjust the common rail pressure. Abnormal conditions will lead to engine output decline, or even shutdown.................................................