"P" position

WARNING: This page is about a different car, the 2007 Nissan Quest. However, it is still accessible from the selected car via links, so may be relevant.

The same as for the "N" position, both the forward clutch and the direct clutch are released, so torque from the input shaft drive is not transmitted to the output shaft.
The parking pole linked with the selector lever meshes with the parking gear and fastens the output shaft mechanically.

Fig 1: Identifying Power Transmission N And P Position
Courtesy of NISSAN MOTOR CO., U.S.A.