• The AIR relay supplies power to the AIR pump and drives the pump.

• The AIR solenoid valve opens and closes the valve switching to feed intake manifold vacuum and BARO which is fed to the actuator in the AIR control valve.

• At cold-engine start, the AIR solenoid valve switches for vacuum feed, and opens the AIR control valve. The AIR pump relay also turns on, driving the AIR pump and sending air to the exhaust port through the AIR control valve. As a result, the unburnt gas in the air and exhaust gas are mixed and it recombusts to activate the catalytic converter rapidly.


• At cold-engine start and when the catalytic converter temperature is low, the AIR pump relay turns on to drive the AIR pump. When the AIR pump relay turns on, an on signal is also sent to the AIR solenoid valve simultaneously.

• The ignition timing, the fuel injection amount and the throttle valve opening angle are controlled intentionally so that the air mixes with the exhaust gas easily, and the secondary air amount corresponding to the unburnt gas amount is discharged for rapid and complete reburn.