Secondary Air Supply

Fig. 45 Secondary air supply system (Federal):

FEDERAL VEHICLES

Secondary air is used by the catalytic converter to complete oxidation and reduction of exhaust gas emissions. On Federal vehicles, Fig. 45. 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. The secondary air control valve is opened by the ECU based on coolant temperature, engine speed, time, and idle position. The air control valve is supplemented by a second reed valve which supplies additional air to the upstream side of the rear catalytic converter.

Fig. 46 Secondary air supply system (California):

CALIFORNIA VEHICLES

Secondary air is used by the catalytic converter to complete oxidation and reduction of exhaust gas emissions. On California vehicles, Fig. 46. 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. The secondary air control valve is opened by the ECU based on coolant temperature, engine speed, time, and idle position.