DTC P0733 A/T 3RD Gear Function: Description

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.

This malfunction will not be detected while the A/T Check indicator lamp is indicating another self-diagnosis malfunction.
This malfunction is detected when the A/T does not shift into third gear position as instructed by the TCM. This is not caused by electrical malfunction (circuits open or shorted) but by mechanical malfunction such as control valve sticking, improper solenoid valve operation, etc.

Fig 1: Proper Shift Solenoid Valve Operation Table

Courtesy of NISSAN MOTOR CO., U.S.A.