Infiniti F50. Manual - part 819

STC-1

STEERING CONTROL SYSTEM

G  STEERING

CONTENTS

C

D

E

F

H

I

J

K

L

M

SECTION 

A

B

STC

STEERING CONTROL SYSTEM

EPS

ELECTRICALLY CONTROLLED POWER STEER-
ING SYSTEM  .............................................................. 2

Precautions .............................................................. 2

BEFORE DIAGNOSING THE POWER STEER-
ING SYSTEM, ENSURE THAT  ............................. 2

Description ............................................................... 2

SYSTEM DESCRIPTION  ...................................... 2
FAIL-SAFE FUNCTION ......................................... 2

HYDRAULIC CIRCUIT  .......................................... 3

Component Parts Location  ....................................... 3
Trouble Diagnosis ..................................................... 4

WIRING DIAGRAM  ............................................... 4
PRECAUTIONS FOR DIAGNOSIS  ....................... 6
INSPECTION BEFORE TROUBLE DIAGNOSIS ..... 6
DIAGNOSIS PROCEDURE  .................................. 6

Control Unit Inspection Table .................................... 9

STC-2

[EPS]

ELECTRICALLY CONTROLLED POWER STEERING SYSTEM

[EPS]

ELECTRICALLY CONTROLLED POWER STEERING SYSTEM

PFP:28500

Precautions

EGS0007V

BEFORE DIAGNOSING THE POWER STEERING SYSTEM, ENSURE THAT
Vehicle Stopped

1.

Power steering components (gears, oil pump, pipes, etc.) Are free from leakage, and that oil level is cor-
rect.

2.

Tires are inflated to specified pressure and are of specified size, and that steering wheel is a genuine Nis-
san part.

3.

Suspension utilizes the original design, and is free of modifications which increase vehicle weight.

4.

Wheel alignment is adjusted properly.

Vehicle In Operation

1.

Understand the trouble symptom.

2.

Engine is operation properly

Description

EGS0007W

SYSTEM DESCRIPTION

The power steering system is a twin orifice type, which uses a vehi-
cle-speed sensing, electronic control design. Solenoid valve sensi-
tivity is controlled in response to vehicle speed to achieve optimum
steering effort.

FAIL-SAFE FUNCTION

The fail-safe function operates to regulate solenoid valve operation
in response to engine speed, thereby maintaining the required steer-
ing force.

Fail-Safe Input Conditions

NOTE:
When the engine is revved up to 1,500 rpm or more for at least 10 seconds with vehicle at standstill, the fail-
safe function operates; however, this is not a matter of concern. The fail-safe function can be released by driv-
ing vehicle of a speed of greater than 1.4 km/h (0.9 MPH) or by turning ignition switch from “OFF” to “ON”.

SST696CA

SST697CB

Fail-safe input conditions

Release conditions

No vehicle speed signal entered for at least 10 seconds while 
driving at an engine speed of greater than 1,500 rpm.

●

A vehicle speed signal of greater than 1.4 km/h (0.9 MPH) is 
entered,

●

Ignition switch is turned from 

″

OFF

″

 to 

″

ON

″

. 

A vehicle speed signal of greater than 30 km/h (19 MPH) or 
abruptly drops below 2 km/h (1 MPH).

ELECTRICALLY CONTROLLED POWER STEERING SYSTEM

STC-3

[EPS]

C

D

E

F

H

I

J

K

L

M

A

B

STC

HYDRAULIC CIRCUIT

NOTE:
On models equipped with active damper suspension system, the solenoid valve is controlled by active damper
suspension control unit, as shown in the above drawing. For 

″

 Wiring Diagrams 

″

 and 

″

 Trouble Diagnoses 

″

 of

these models. Refer to 

SCS-2, "TROUBLE DIAGNOSIS FOR ACTIVE DAMPER SUSPENSION"

 .

Component Parts Location 

EGS0007X

SST838C

SGIA0042E

STC-4

[EPS]

ELECTRICALLY CONTROLLED POWER STEERING SYSTEM

Trouble Diagnosis

EGS0007Y

WIRING DIAGRAM

TGWM0001E