Infiniti M45 (Y34). Manual - part 794

STC-1

STEERING CONTROL SYSTEM

G  STEERING

CONTENTS

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SECTION 

STC

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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
Wiring Diagram  ........................................................ 4
Control Unit Input/Output Signal Standard  ............... 6
Trouble Diagnosis  .................................................... 7

PRECAUTIONS FOR DIAGNOSIS ....................... 7
INSPECTION BEFORE TROUBLE DIAGNOSIS 

..... 7

DIAGNOSIS PROCEDURE  .................................. 7

TILT/TELESCOPIC

TILT & TELESCOPIC SYSTEM  ................................ 11

System Description ................................................. 11

OPERATION ........................................................ 11

Component Parts and Harness Connector Location 

... 11

Wiring Diagram ....................................................... 12
BCM Input/Output Signal Standard  ........................ 13
Preliminary Check  .................................................. 14

POWER SUPPLY AND GROUND CIRCUIT 
INSPECTION ...................................................... 14

Symptom 1: Telescopic System Does Not Operate ... 15
Symptom 2: Tilt System Does Not Operate ............ 18

STC-2

[EPS]

ELECTRICALLY CONTROLLED POWER STEERING SYSTEM

[EPS]

ELECTRICALLY CONTROLLED POWER STEERING SYSTEM

PFP:28500

Precautions

AGS0003E

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 symptom.

2.

Engine is operation properly

Description

AGS0003F

SYSTEM DESCRIPTION

The power steering system is a twin orifice type, which uses a vehicle-speed sensing, electronic control
design. Solenoid valve sensitivity 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 steering 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”.

SGIA0326E

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]

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F

H

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STC

HYDRAULIC CIRCUIT

Component Parts Location 

AGS0003G

SGIA0327E

SGIA0042E

STC-4

[EPS]

ELECTRICALLY CONTROLLED POWER STEERING SYSTEM

Wiring Diagram

AGS0009N

TGWA0008E