Operation Principle

WARNING: This page is about a different car, the 2011 Nissan Murano. However, it is still accessible from the selected car via links, so may be relevant.

During Parking (When Turning The Steering Wheel To The Right.)

Fig 1: Parking Operation Diagram

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

Power steering solenoid valve is closed while a vehicle is stopped.
Pinion "1R", "2R" and "3R" are closed depending on steering torque of steering wheel.
Oil pressure "P" in the gear housing assembly is the sum of oil pressures occurred in "2R" and "3R". This results in a light steering force because of high pressure.

During High-speed Operation

Fig 2: High-Speed Operation Diagram

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

Power steering solenoid valve is opened during high-speed operation.
Pinion "1R", "2R" and "3R" are closed depending on steering torque of steering wheel.
Oil pressure "2R" does not occur because the power steering solenoid valve is on full throttle.
Oil pressure "P" in the gear housing assembly includes only oil pressure occurred in "3R" and results in a heavy steering force.