2. Check Harness Between TCM & A/T Device (Manual Mode Switch)

WARNING: This page is about a different car, the 2004 Nissan Maxima. However, it is still accessible from the selected car via links, so may be relevant.

Turn ignition switch "OFF".
Disconnect the TCM connector.
Check the continuity between TCM connector terminals 5, 6, 16, 19 and ground.

Fig 1: Manual Mode Switch Circuit Continuity Specifications
Courtesy of NISSAN MOTOR CO., U.S.A.

Fig 2: Checking Continuity
Courtesy of NISSAN MOTOR CO., U.S.A.
If OK, check harness for short-circuit to ground or power source.

OK or NG

OK: GO TO 4 .
NG: GO TO 3.