Air Injection Control Valve: Description and Operation

AIR Shut-Off Valves
The AIR shut-off valves are named combination valves and are vacuum operated. These components incorporate a shut-off valve and a check valve assembled together in one unit and are serviced together as an assembly. When the AIR system is commanded ON, engine vacuum is applied to the valves by the AIR solenoid. The vacuum opens the AIR shut-off valves and allows air from the AIR pump to enter into the exhaust stream.

Check Valve
The check valve that is designed and incorporated in the combination valve prevents back flow of exhaust gases into the AIR system. Any pipes/hoses that have shown indications of having heat damage may indicate a check valve failure.