September 30: LEMON manuals is back up on a temporary server! Slowness is possible
Water Temperature Gauge
WARNING: This page is about a different car, the 2009 Nissan Sentra. However, it is still accessible from the selected car via links, so may be relevant.
The water temperature gauge indicates the engine coolant temperature.
The ECM provides an engine coolant temperature signal to the combination meter via CAN communication lines.
Courtesy of NISSAN MOTOR CO., U.S.A.