EPS System Function

WARNING: This page is about a different car, the 2006 Infiniti G35. However, it is still accessible from the selected car via links, so may be relevant.

Vehicle speed sensing electronically controlled power steering (that properly controls the steering force by the vehicle speed) has been adopted. When it is normal, it controls the power steering solenoid valve according to the vehicle speed as shown in the figure and makes the steering force proper.
For schematic, wiring diagram and trouble diagnosis, refer to ,"SCHEMATIC ", ,"WIRING DIAGRAM -RAS - ", ,"DIAGNOSIS CHART BY SYMPTOM 2 ", because EPS is controlled by RAS control unit.

Fig 1: EPS System Function Graph - Voltage To Speed
Courtesy of NISSAN MOTOR CO., U.S.A.