Infiniti FX35, FX50 (S51). Manual - part 1774

EPS SYSTEM

STC-37

< SYSTEM DESCRIPTION >

[WITH REAR ACTIVE STEER]

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Component Parts Location

INFOID:0000000005235362

Component Description

INFOID:0000000005235363

1.

Power steering solenoid valve

2.

RAS control unit

3.

RAS motor relay

A.

Steering gear assembly

B.

Inside the rear wheel house finisher 
(Left)

: Vehicle front

JSGIA0771ZZ

Component parts

Reference/Function

RAS control unit

• The power steering solenoid valve activation voltage is controlled by each sensor signal.
• The power steering solenoid valve activation voltage is controlled by RAS control unit for 

maintaining the power steering force in the fail-safe mode. (EPS system is controlled by 
the engine speed signal if the vehicle speed signal error is detected.)

ABS actuator and electric unit (control 
unit)

STC-65, "Description"

ECM

STC-69, "Description"

Power steering solenoid valve

STC-83, "Description"

STC-38

< SYSTEM DESCRIPTION >

[WITH REAR ACTIVE STEER]

DIAGNOSIS SYSTEM (RAS CONTROL UNIT)

DIAGNOSIS SYSTEM (RAS CONTROL UNIT)

Diagnosis Description

INFOID:0000000005235364

DESCRIPTION

The RAS warning lamp in the combination meter will flicker according to the self-diagnostic results. As for the
details of the RAS warning lamp flickering patterns.

DIAGNOSTIC PROCEDURE

1.

Start the engine.

2.

Perform the following procedure within 10 seconds after engine start.
• Turn steering wheel left and right at 20

°

 or more and 5 times

• Depress the brake pedal 5 times or more

3.

Read the flickering of RAS warning lamp.
NOTE:
When the RAS warning lamp flashes 4 Hz and continues repeating it, the system is normal.

JUDGMENT SELF-DIAGNOSIS CODE

When a malfunction is detected, the malfunction route is indicated by flickering of the RAS warning lamp.

NOTE:
When the RAS warning lamp flashes 4 Hz and continues repeating it, the system is normal.

SGIA1453E

Flickering 

pattern

Display items

Malfunction detected condition

Check item

11

RAS control unit

Malfunction has occurred inside RAS control unit.

STC-42

, 

STC-48

 or 

STC-50

12

Motor power supply

Battery voltage circuit malfunction of RAS motor

STC-52

13

Motor output

When the RAS motor current value is 10 A or more, 
actual output is excessively low and the condition con-
tinues for some time.

STC-44

21

Vehicle speed signal

• Malfunction is detected in vehicle speed signal that 

is output from ABS actuator and electric unit (control 
unit) via CAN communication.

• Improper signal is input vehicle speed.

STC-65

22

Steering angle sensor signal

• Malfunction is detected in steering angle sensor sig-

nal that is output from steering angle sensor via 
CAN communication.

• Improper signal is input steering angle sensor.

STC-67

, 

STC-71

, 

STC-73

 or 

STC-75

24

Rear wheel steering angle 
(main)

• The rear wheel steering angle sensor (main) output 

signal is malfunctioning.

• The rear wheel steering angle sensor (main) power 

supply value is malfunction.

• The output signal value differs between rear wheel 

steering angle sensor (main) and (sub). 

STC-56

, 

STC-59

 or 

STC-62

25

Rear wheel steering angle 
(sub)

• The rear wheel steering angle sensor (sub) output 

signal is malfunctioning.

• The rear wheel steering angle sensor (sub) power 

supply value is malfunction.

• The output signal value differs between rear wheel 

steering angle sensor (main) and (sub). 

STC-56

, 

STC-59

 or 

STC-62

DIAGNOSIS SYSTEM (RAS CONTROL UNIT)

STC-39

< SYSTEM DESCRIPTION >

[WITH REAR ACTIVE STEER]

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ERASE SELF-DIAGNOSIS

• In order to make it easier to find the cause of hard-to-duplicate malfunctions, malfunction information is

stored into the control unit as necessary during use by the user. This memory is not erased no matter how
many times the ignition switch is turned ON and OFF.

• However, this information is erased or by erasing the memory using the CONSULT-III.

CONSULT-III Function 

INFOID:0000000005235365

FUNCTION

CONSULT-III can display each diagnostic item using the diagnostic test modes shown below.

SELF-DIAG RESULT MODE

Display Item List

Refer to 

STC-102, "DTC Index"

.

FREEZE FRAME DATA (FFD)

RAS control unit can record the following information when a DTC is detected.

26

VDC

• Malfunction is detected in VDC malfunction signal 

that is output from ABS actuator and electric unit 
(control unit) via CAN communication.

•  ABS actuator and electric unit (control unit) outputs 

the malfunction signal.

• Improper signal is input VDC malfunction signal.

STC-77

33

Engine speed signal

• Malfunction is detected in engine speed signal that 

is output from ECM via CAN communication.

• Improper signal is input engine speed.

STC-69

No flicker-

ing

Stop lamp switch

Stop lamp switch circuit is shorted or open.

STC-87

Flickering 

pattern

Display items

Malfunction detected condition

Check item

Diagnostic test mode

Function

ECU identification

RAS control unit part number can be read.

Self-diagnostic results

• Self-diagnostic results can be read and erased quickly.
• A vehicle state can be stored when a DTC is detected. (Freeze frame data)

Data monitor

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

Active test

Diagnostic Test Mode in which CONSULT-III drives some actuators apart from the RAS control unit 
and also shifts some parameters in a specified range.

Freeze Frame Data Item

Description

VHCL SPEED SE

A vehicle speed at malfunction detection is indicated.

STEERING ANG

A steering angle at malfunction detection is indicated.

ENGINE SPEED

A engine speed at malfunction detection is indicated.

POWER STR SOL

A current value of the power steering solenoid valve at malfunction detection is indicat-
ed.

RR ST ANG-MAI

A voltage of the rear wheel steering angle sensor (main) at malfunction detection is in-
dicated.

RR ST ANG-SUB

A voltage of the rear wheel steering angle sensor (sub) at malfunction detection is indi-
cated.

RR ST ANG-VOL

A power supply voltage of the rear wheel steering angle sensor at malfunction detection 
is indicated.

C/U VOLTAGE

A power supply voltage value of RAS control unit at malfunction detection is indicated.

MOTOR VOLTAGE

A voltage value of RAS motor at malfunction detection is indicated.

MOTOR CURRENT

A current value of RAS motor at malfunction detection is indicated.

MTR CRNT OPE

A current value input to RAS motor at malfunction detection is indicated.

STC-40

< SYSTEM DESCRIPTION >

[WITH REAR ACTIVE STEER]

DIAGNOSIS SYSTEM (RAS CONTROL UNIT)

DATA MONITOR MODE

Display Item List

ACTIVE TEST MODE

Description

• RAS actuator assembly activation is checked according to the control signal from CONSULT-III.
• The control signal forcibly activates (ON/OFF) RAS actuator assembly, performs the self-diagnosis and

checks each sensor in “SELF DIAGNOSTIC MODE”.

CAUTION:

Perform the active test while the vehicle is stopped.

Standard value

RR ANGLE OPE

A angle command value is indicated for activating RAS motor at malfunction detection 
is indicated.

STOP LAMP SW

A stop lamp switch status at malfunction detection is indicated.

HICAS RELAY

A RAS motor relay condition at malfunction detection is indicated.

FAILSAFE

A fail-safe mode status of RAS control unit at malfunction detection is indicated.

WARNING LAMP

A RAS warning lamp condition at malfunction detection is indicated.

Freeze Frame Data Item

Description

Monitor item (Unit)

Remarks

VHCL SPEED SE [km/h] or [mph]

The vehicle speed signal from ABS actuator and electric unit (control unit) is indicated via 
CAN communication line.

STEERING ANG [

°

]

The steering angle sensor signal from the steering angle sensor is indicated via CAN com-
munication line.

ENGINE SPEED [rpm]

The engine speed signal from ECM is indicated via CAN communication line.

POWER STR SOL [A]

The current value of the power steering solenoid valve is indicated.

RR ST ANG-MAI [V]

The voltage of the rear wheel steering angle sensor (main) is indicated.

RR ST ANG-SUB [V]

The voltage of the rear wheel steering angle sensor (sub) is indicated.

RR ST ANG-VOL [V]

The power supply voltage of the rear wheel steering angle sensor is indicated.

C/U VOLTAGE [V]

The power supply voltage value of RAS control unit is indicated.

MOTOR VOLTAGE [V]

The voltage value of RAS motor is indicated.

MOTOR CURRENT [A]

The current value of RAS motor is indicated.

MTR CRNT OPE [A]

The current value input to RAS motor is indicated.

RR ANGLE OPE [

°

]

The angle command value is indicated for activating RAS motor.

STOP LAMP SW [On/Off]

The stop lamp switch status is indicated.

HICAS RELAY [On/Off]

RAS motor relay condition is indicated.

FAILSAFE [On/Off]

The fail-safe mode status of RAS control unit is indicated.

WARNING LAMP [On/Off]

RAS warning lamp ON/OFF condition is indicated.

Select test item

Control signal

Remarks

SELF DIAGNOSTIC MODE

ON

CAUTION:

Perform the active test while the vehicle 
is stopped.

RAS actuator assembly activates. It acti-
vates in the same direction as the steering 
angle by inputting the steering angle.

OFF

RAS actuator assembly stops the activa-
tion.

Monitor item

Active test “ON”

STEERING ANG

0

°

 (Neutral)

R 90

°

L 90

°

RR ST ANG-MAI

2.4 V

Approx. 4.4 V

Approx. 0.4 V