WARNING: This page is about a different car, the 2002 Nissan Sentra. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: Engine Speed Signal Circuit And Identifying Connectors
Courtesy of NISSAN MOTOR CO., U.S.A.
TCM TERMINALS AND REFERENCE VALUE MEASURED BETWEEN EACH TERMINAL AND 25 OR 48 (TCM GROUND)
Fig 2: Transmission Control Module Terminal Reference Values