Disconnect the vacuum hose (A) and remove the PCV valve (B).
Remove the PCV valve.
Insert a thin stick(A) into the PCV valve(B) from the threaded side to check that the plunger moves.
If the plunger does not move, the PCV valve is clogged. Clean it or replace.
Install the PCV valve and tighten to the specified torque.
PCV Valve installation :
7.8 ~ 11.8 N·m (0.8 ~ 1.2 kgf·m, 5.8 ~ 8.7lbf·ft)