The air cut solenoid valve is installed in the rear of the cylinder head and opens or closes the passage of the secondary air to the engine exhaust port. When activating the air pump, the ECM turns the air cut solenoid valve ON and opens the valve so that the air is supplied to the exhaust port. The ECM turns the air cut solenoid valve OFF and closes the valve to prevent air blow back. Then the ECM deactivates the air pump. The ECM does not activate the air cut solenoid valve directly. The ECM controls the air cut solenoid valve by turning the air cut solenoid valve relay ON/OFF.