Air Injection System (Secondary Air Supply)
The air injection system consists of a secondary air filter, reed valve, secondary air control valve and secondary air solenoid valve. This system reduces exhaust emissions by promoting oxidation of exhaust gases.
The ECU monitors engine speed, intake airflow, coolant temperature and idle position. When all required conditions are met, the ECU activates the solenoid valve to supply secondary air to exhaust manifold during engine warm-up, hot-start and deceleration modes of operation.
When the ECU activates the solenoid valve, intake manifold vacuum opens the secondary air control valve. The control valve allows additional air to enter the exhaust manifold. The reed valve, actuated by vacuum pulsations in exhaust manifold, controls the amount of additional air entering the exhaust manifold.