Improper Door Action

If door did not respond as indicated above (did not rise or fall), first check to see if door is binding. If okay, then check air bleed valve.
Disconnect and plug hose leading to air bleed valve, then crank engine for about 5 seconds.
Air control valve door should rise and remain up for at least 3 seconds. If it does, replace air bleed valve and repeat test.
If door does not rise or remain open, proceed with testing of air control diaphragm and check valve.
Disconnect vacuum hose from air control diaphragm and remove deflector plate. Raise air control valve door manually and, while blocking inlet pipe, release valve door.

Fig 1: Air Control Diaphragm & Check Valve Test
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Block inlet pipe as shown.
If valve door remains up, replace check valve and retest. If valve door drops to closed position, replace air control diaphragm and retest.