2004 Ford F-250 Super Duty - Smog Pump Check Valve

An air pump check valve is one of the components of the secondary air injection or smog system. The air pump check valve allows clean air generated by the air pump or smog pump to dilute the emissions from the vehicle's exhaust while keeping the exhaust from flowing back into the smog system. By monitoring a single direction of air flow, the air pump check valve can help maintain a cleaner exhaust and lower emission levels.