WARNING: This page is about a different car, the 2005 Infiniti G35. However, it is still accessible from the selected car via links, so may be relevant.
Check the resistance between terminals 1 and 2.
Fig 1: Fuel Level Sensor Unit (Sub) Terminals Resistance Table
Courtesy of NISSAN MOTOR CO., U.S.A.
Fig 2: Checking Resistance Between Terminals 2 And 5 Of Fuel Level Sensor Unit (Sub)