EPS system

EPS system enters the fail-safe mode (that allows the steering force to be controlled without impairing the driveability) if any of the input/output values to/from EPS system (power steering control unit) deviate from the standard range.
NOTE: The system enters the fail-safe mode if the engine speed remains at 1,500 RPM or more for over 10 seconds while the vehicle is stopped. This is normal.

The fail-safe function is canceled when a vehicle speed signal of 2 km/h (1.2 MPH) or more is inputted or the ignition switch is turned OFF→ON. EPS system restores the normal operation at that time.

Fig 1: Solenoid Valve Voltage Graph

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

REFERENCE CHART

Mode	Warning lamp	DTC	Detection point (malfunction part)	Error area and root cause
Fail-safe	-	-	Vehicle speed signal input	Engine speed is 1,500 RPM or more and there is no vehicle speed signal input for over 10 seconds during vehicle travel. Vehicle speed signal has abruptly dropped from 30 km/h (19 MPH) or more to 2 km/h (1.2 MPH) or less within 1.4 seconds.