Nissan Rogue. Manual - part 1144

STC-6

< SYSTEM DESCRIPTION >

COMPONENT PARTS

EPS Control Unit

INFOID:0000000011279637

• EPS control unit (1) is installed to steering column assembly.

• EPS control unit performs an arithmetical operation on data, such

as steering wheel turning force (sensor signal) from the torque

sensor, vehicle speed signal, etc. Then it generates an optimum

assist torque signal to the EPS motor according to the driving con-

dition.

• EPS control unit decreases the output signal to EPS motor during

continuous extreme use of the power steering function (e.g., full

steering) for protection of the EPS motor and EPS control unit

(Overload protection control).

EPS Motor, Torque Sensor, Reduction Gear

INFOID:0000000011279638

EPS motor (1), torque sensor (2) and reduction gear (3) are installed

to steering column assembly.

EPS MOTOR

EPS motor provides assist torque in proportion to the control signal from the EPS control unit.

TORQUE SENSOR

Torque sensor detects the steering torque and transmits the signal to the EPS control unit.

REDUCTION GEAR

Reduction gear increases the assist torque provided from the EPS motor, and outputs to the column shaft.

JSGIA0852ZZ

JSGIA0853ZZ

SYSTEM

STC-7

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SYSTEM

EPS SYSTEM
EPS SYSTEM : System Description

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SYSTEM DIAGRAM

INPUT/OUTPUT SIGNAL

Communicates the signal from each control unit via CAN communication. 

DESCRIPTION

JSGIA0877GB

Control unit

Signal status

ECM

• Transmits the following signal to EPS control unit via CAN communication:
- Engine status signal 

ABS actuator and electric unit (con-
trol unit)

• Transmits the following signal to EPS control unit via CAN communication:
- Vehicle speed signal (ABS)

Combination meter

• Transmits the following signal to EPS control unit via CAN communication:
- Vehicle speed signal (Meter)
• Receives the following signal from EPS control unit via CAN communication:
- EPS warning lamp signal 

STC-8

< SYSTEM DESCRIPTION >

SYSTEM

• EPS control unit performs an arithmetical operation on data, such

as steering wheel turning force (sensor signal) from the torque

sensor, vehicle speed signal, etc. Then it generates an optimum

assist torque signal to the EPS motor according to the driving con-

dition.

• In case of an error in the electrical system, the fail-safe function

stops output signals to the EPS motor. Refer to 

STC-8, "EPS SYS-

TEM : Fail-Safe"

.

• EPS control unit decreases the output signal to EPS motor during

extreme use of the power steering function (e.g., full steering) for

protection of the EPS motor and EPS control unit (Overload pro-

tection control).

• Extensive steering at low speed will cause the EPS control unit

and EPS motor to heat up. Once temperature reaches the critical

point, the EPS control unit will reduce current to reduce heat up.

System will recover as temperature lowers (reduced or no assis-

tance).

EPS WARNING LAMP INDICATION

• Turns ON when there is a malfunction in the EPS system. If ON, fail-safe mode is engaged and the system

enters a manual steering state (turning force at steering wheel becomes heavy).

• Also turns ON when ignition switch is turned ON, for purpose of lamp check. Turns OFF after the engine

starts, if system is normal.

CAUTION:

EPS warning lamp also turns ON due to data reception error, CAN communication error etc.

EPS SYSTEM : Fail-Safe

INFOID:0000000011279640

• If any malfunction occurs in the system and the control unit detects the malfunction, the EPS warning lamp in

the combination meter turns ON to indicate system malfunction.

• When EPS warning lamp is ON, the system enters into a manual steering state. (turning force at steering

wheel becomes heavy.)

• Under abnormal vehicle speed signal conditions, vehicle speed is judged as constant.

EPS SYSTEM : Protection Function

INFOID:0000000011279641

While overload protection control is activated, assist torque gradually decreases and the steering wheel turn-

ing force becomes heavy. Assist torque returns to normal if the steering wheel is not turned for a while.

JSGIA1102GB

Condition

EPS warning lamp

Ignition switch ON. (Lamp check)

ON

Engine running.

OFF

EPS system malfunction [Other diagnostic item]

ON

DIAGNOSIS SYSTEM (EPS CONTROL UNIT)

STC-9

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DIAGNOSIS SYSTEM (EPS CONTROL UNIT)

CONSULT Function

INFOID:0000000011279642

FUNCTION

CONSULT can display each diagnostic item using the diagnostic test modes shown following:

*: The following diagnosis information is cleared by erasing:

• DTC

• Freeze frame data (FFD)

ECU IDENTIFICATION

Displays the part number stored in the control unit.

SELF-DIAG RESULTS MODE

Refer to 

STC-13, "DTC Index"

.

When “CRNT” is displayed on “Self Diagnostic Result”:

• The system is presently malfunctioning.

When “PAST” is displayed on “Self Diagnostic Result”:

• System malfunction in the past is detected, but the system is presently normal.

FREEZE FRAME DATA (FFD)

The following vehicle status is recorded when DTC is detected and is displayed on CONSULT:

DATA MONITOR MODE

NOTE:

The following table includes information (items) inapplicable to this vehicle: For information (items) applicable

to this vehicle, refer to CONSULT display items.

Diagnostic test mode

Function

ECU identification

The part number stored in the control unit can be read.

Self diagnostic result

Self-diagnostic results and freeze frame data can be read and erased quickly.

*

Data monitor

Input/Output data in the EPS control unit can be read.

Item name

Display item

IGN COUNTER
(0 – 39)

The number of times that ignition switch is turned ON after the DTC is detected is displayed:
• When “0” is displayed: It indicates that the system is presently malfunctioning.
• When except “0” is displayed: It indicates that system malfunction in the past is detected, but the system is pres-

ently normal.
NOTE:
Each time when ignition switch is turned OFF to ON, numerical number increases in 1

→2→3...38→39.

When the operation number of times exceeds 39, the number do not increase and “39” is displayed until self-
diagnosis is erased.

Monitor item (Unit)

Remarks

BATTERY VOLT (V)

Displays the power supply voltage for EPS control unit.

TORQUE SENSOR (Nm)

Displays steering wheel turning force detected by torque sensor.

MOTOR CURRENT (A)

Displays the current value consumed by EPS motor.

*1

MOTOR SIG (A)

Displays the current commanded value to EPS motor.

ASSIST TORQUE (Nm)

Displays assist torque of EPS motor being output by the electric power steering.

C/U TEMP (

°C) or (°F)

Displays the temperature of the EPS control unit.

ASSIST LEVEL (%)

Normally displays 100%. In case of an excessive stationary steering, the assist 
curvature gradually falls. However, it return to 100% when left standing.

*2

VEHICLE SPEED (km/h) or (MPH)

Vehicle speed is displayed from vehicle speed signal via CAN communication.

*3

WARNING LAMP (On/Off)

EPS warning lamp control status is displayed.

ENGINE STATUS (Stop/Run)

Engine speed is displayed from engine status signal via CAN communication.