Air Injection Control Valve: Testing and Inspection

NOTE: Engine must be at normal operating temperature.

1. Disconnect hoses from air control valve, noting which hose was connected to downstream port and which hose to upstream port.
2. Start engine and disconnect vacuum hose from small valve nipple.

NOTE: There should be vacuum at vacuum hose when engine coolant temperature is below about 160° F, and no vacuum when temperature is above 160° F. If coolant is below 160° F and there is no vacuum present at hose, check hose for air leaks. If there are no leaks, replace AGE/CTO switch.

3. Air pressure should be present at air control valve port which connects to downstream hose. A small amount of air pressure should be present at upstream port of air control valve.
4. Apply at least 10 inches Hg of vacuum to small nipple on air control valve. Air pressure should be present at upstream port and very little air pressure at downstream port.