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: Disconnecting Ventilation Hose
Courtesy of KIA MOTORS AMERICA, INC.
If vacuum is not felt, clean the PCV valve and ventilation hose in cleaning solvent, or replace if necessary.