Infiniti G35 (V35) Sedan. Manual - part 1286

STC-34

< FUNCTION DIAGNOSIS >

[WITH 4WAS]

4WAS SYSTEM

- The steering gear ratio changes according to the vehicle speed.

The steering wheel operation (steering angle) load decreases.

When Driving at Low Speed

• Increased front wheel angle gains the best front wheel angle by

minimum steering wheel operation (steering angle).

When Driving at Middle Speed

• Increased steering angle and controlling the rear wheel steering

angle (steering angle) same as the steering wheel operation ele-
vate the reaction of the vehicle yaw rate and lateral acceleration. It
decreases the vehicle sideslip angle.

When Driving at High Speed

• Controlling the rear wheel steering angle (steering angle) same as

the steering wheel operation and decreasing the front steering
wheel angle elevate the reaction of the vehicle and the vehicle sta-
bleness.

Operation Feature

4WAS FRONT ACTUATOR

• It is driven by 4WAS front motor.
• The front steering gear ratio (4WAS front actuator) changes with 4WAS front motor and the gear shaft when

releasing the lock structure (4WAS front lock solenoid valve).
NOTE:
The lock structure is released when turning 4WAS lock solenoid valve ON.

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4WAS SYSTEM

STC-35

< FUNCTION DIAGNOSIS >

[WITH 4WAS]

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• The lock structure (holder) absorbs force and applies the lock when applying strong force to 4WAS front

actuator.

CAUTION:

Replace 4WAS front actuator when the system returns an error because excessive force (rotating
direction) outside is applied to 4WAS front actuator.

4WAS REAR ACTUATOR

• It is driven by 4WAS rear motor.
• The toe-stiffness of rear wheels is maintained against the road external force because the irreversible effi-

ciency performance hypoid gear is used.

• The power from the pinion gear (motor side) is transmitted, but the pinion gear does not rotate as caused by

the gear mechanical characteristics (teeth angle) even though the ring gear (tire side) starts to rotate.

Component Parts Location

INFOID:0000000000958736

1.

Steering angle sensor

2.

4WAS warning lamp

3.

4WAS front control unit

4.

4WAS front actuator

5.

4WAS rear motor

6.

4WAS rear actuator

7.

Rear wheel steering angle sensor

8.

4WAS main control unit

9.

4WAS rear motor relay

10
.

Noise suppressor

A.

combination switch

B.

Inside combination meter

C.

Inside the instrument driver lower 
panel

D.

Rear suspension

E.

Inside the trunk side finisher (left)

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STC-36

< FUNCTION DIAGNOSIS >

[WITH 4WAS]

4WAS SYSTEM

Component Description

INFOID:0000000000958737

*: Communication line between 4WAS front control unit and 4WAS main control unit

Component parts

Reference/Function

4WAS front control unit

STC-55, "Description"

4WAS front actuator

The front wheel steering angle is activated.

Front wheel steering angle sensor

The front wheel steering angle increased/decreased degree is detected. It is output to 4WAS 
front control unit.

4WAS front motor

The front wheel steering angle increased/decreased degree is activated.

4WAS front lock solenoid valve

Secure the inside of 4WAS front actuator temporarily. (It operates when performing active 
test with fail-safe function and CONSULT-III.)

Steering angle sensor

STC-112, "Description"

4WAS main control unit

STC-87, "Description"

4WAS rear actuator

The rear wheel steering angle is activated.

Rear wheel steering angle sensor

The rear wheel steering angle increased/decreased degree is detected. It is output to 4WAS 
main control unit.

4WAS rear motor

4WAS rear actuator is activated.

ABS actuator and electronic unit (con-
trol unit)

STC-110, "Description"

ECM

STC-115, "Description"

Combination meter

It mainly transmits the following signals from 4WAS main control unit with CAN communica-
tion.
• 4WAS warning lamp signal

Power steering solenoid valve

The power steering oil pressure in the gear housing assembly is controlled.

Stop lamp switch

The stop lamp switch condition is detected.

EPS SYSTEM

STC-37

< FUNCTION DIAGNOSIS >

[WITH 4WAS]

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EPS SYSTEM

System Diagram

INFOID:0000000000958738

System Description

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DESCRIPTION

• The electronic control power steering system controls the power steering solenoid valve with 4WAS main

control unit.

• The power steering solenoid valve control changes the power

steering solenoid valve activation voltage according to the vehicle
speed.

OPERATION PRINCIPLE

During Parking (When Turning The Steering Wheel To The Right.)

1.

Power steering solenoid valve is closed while a vehicle is stopped.

2.

Pinion “1R”, “2R” and “3R” are closed depending on steering torque of steering wheel.

3.

Oil pressure “P” in the gear housing assembly is the sum of oil pressures occurring in “2R” and “3R”. This
results in a light steering force because of high pressure.

During High-speed Operation

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