Secondary Air Supply

Fig. 95 Secondary air supply system diagram:

Secondary air is used by the catalytic converter to complete oxidation and reduction of exhaust gas emissions. The secondary air supply system uses an electric secondary air control solenoid valve controlled by the ECU which in turn controls vacuum to a secondary air control valve, Fig. 95. When the engine coolant is cold or when the vehicle is decelerating, the secondary air control valve is open. A reed valve (internal to the secondary air control valve) then provides secondary air to the exhaust system.