Crankcase Emission Control System: Inspection

Disconnect the ventilation hose from the positive crankcase ventilation (PCV) valve. Remove the PCV valve from the rocker cover and reconnect it to the ventilation hose.
Run the engine at idle and put a finger on the open end of the PCV valve and make sure that intake manifold vacuum can be felt.
NOTE: The plunger inside the PCV valve will move back and forth.

Fig 1: Putting Finger On Open End Of PCV Valve
Courtesy of KIA MOTORS AMERICA, INC.