I tried to find the PCV valve location in the workshop manual but the pictures/illustrations were very vague. I looked at parts suppliers website which showed the valve as fitting into a rubber grommet which leads me to believe the PCV valve is in one of the valve covers. The PCV valve in the previous series of Nissan/Infiniti engine was screwed into the intake manifold and had a rubber hose connecting it to the valve cover. Look for a hose going from the valve cover to the intake manifold to the intake manifold. The outside diameter of the black rubber hose will be about 11/16ths of and inch (17mm) in diameter.
If a PCV valve fails shut an engine may develop oil leaks, if PCV valve fails open it will affect the way an engine idles and may cause emission failure or stalling.