Repair Procedures: Inspection

After disconnecting the vapor hose from the PCV valve, remove the PCV valve.
Reconnect the PCV valve to the vapor hose.
Run the engine at idle, then put a finger over 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 in vacuum.

Fig 1: Inspecting Vapor Hose & PCV Valve
Courtesy of KIA MOTORS AMERICA, INC.
If vacuum is not felt, inspect PCV operation. If operating correctly, clean or replace the vapor hose.