Toyota 12204-20010 Valve Sub-Assy, Ventilation

The PCV valve and hose is located in the valve cover. To check it, disconnect the hose and pull the PCV valve from the cover, then reconnect the hose. With the engine idling at normal operating temperature, place your finger over the valve opening. If there's no vacuum at the valve, check for a plugged hose or valve and replace any plugged or deteriorated hoses. After this, turn off the engine and remove the PCV valve from the hose. Blow through the valve from the valve cover (cylinder head) end. If air will not pass through the valve in this direction, replace it with a new one. To check the PCV valve, first attach a clean section of hose to the cylinder head side of the valve and blow through it - air should pass through easily - then blow through the opposite side of the valve and verify that air doesn't pass through it. When purchasing a replacement PCV valve, make sure it's for your particular vehicle and engine size. Compare the old valve with the new one to make sure they're the same.