Positive Crankcase Ventilation (PCV)

WARNING: This page is about a different car, the 2003 Lexus GX 470. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: PCV valve on this vehicle is called Ventilation Valve.

Install clean hose to ventilation valve. Blow air into cylinder head side. Check that air passes through smoothly. Do NOT suck air through valve. Petroleum substances inside valve are harmful.
Blow air into intake manifold side. Check that air does not pass through smoothly.
If operation is not as specified, replace ventilation valve.
Remove clean hose from ventilation valve.
If circuit or component is faulty, a Diagnostic Trouble Code (DTC) may set. Retrieve DTCs and perform appropriate diagnostic test. See SELF-DIAGNOSTICS - GX470 article.