Air Supply Control Valve

Verify that air is being supplied to valve inlet by disconnecting inlet supply hose. Disconnect hoses at valve outlets "A", "B" and at vacuum nipple. With engine speed at 1500 RPM, airflow should be heard and felt at valve outlet "B" and little or no air at valve outlet "A". See Figure .
Using a direct vacuum line from manifold vacuum source, connect line to vacuum nipple. Airflow should be detected at valve outlet "A" and little or no air at valve outlet "B". If valve fails any test, replace valve. Reconnect all lines.