The position of the turbocharger nozzles is controlled by the ECM. The ECM utilizes the turbocharger control solenoid valve and boost pressure sensor to control the turbocharger nozzles. When no load is applied to the engine, the turbocharger nozzle is open or there is no boost pressure. When load is applied to the engine, the ECM controls the control solenoid valve and closes the turbocharger nozzle. As a result, boost pressure is increased. The ECM controls changes in boost pressure according to the load requirements of the engine. The ECM uses pulse-width modulation (PWM) in the control circuit to control the opening of the solenoid valve.