Operation principle

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

AWD control unit supplies command current to electric controlled coupling (AWD solenoid).

Fig 1: Identifying AWD Solenoid
Courtesy of NISSAN MOTOR CO., U.S.A.
Control clutch is engaged by electromagnet and torque is detected in control clutch.
The cam operates in response to control clutch torque and applies pressure to main clutch.
Main clutch transmits torque to front wheels according to pressing power.
- Transmission torque to rear wheels is determined according to command current.
  
  Fig 2: I-T Characteristics Graph
  Courtesy of NISSAN MOTOR CO., U.S.A.