Infiniti G37 Coupe. Manual - part 1245

INSPECTION AND ADJUSTMENT

STC-31

< BASIC INSPECTION >

[WITH 4WAS]

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CAUTION:

Stop the vehicle.

2.

Steer 90

°

 leftward slowly. Then steer 90

°

 rightward.

3.

Steer 90

°

 leftward slowly again. Then steer 90

°

 rightward. Return the steering wheel to the straight-ahead

position.

4.

Stop the vehicle in the straight-ahead position after driving for a period of time. (Engine running)

>> GO TO 5.

5.

CHECK 4WAS FRONT ACTUATOR

With CONSULT-III

1.

Check “4WAS STR ANG” item on “DATA MONITOR” of 4WAS front control unit.

CAUTION:

Never touch the steering wheel during the service.

2.

Turn the ignition switch OFF.

Is the inspection result normal?

YES

>> GO TO 6.

NO

>> GO TO 1.

6.

PERFORM ACTIVE TEST (SLOW MODE)

With CONSULT-III

1.

Start the engine.

CAUTION:

Stop the vehicle.

2.

Select “SLOW MODE” item on “ACTIVE TEST” of 4WAS front control unit.

3.

Perform “MODE START” of “ACTIVE TEST”.

4.

Steer the steering wheel leftward slowly until the turning stops.

5.

Steer the steering wheel rightward slowly until the turning stops.

Is “OK” indicated on both right and left on “SLOW MODE”?

YES

>> GO TO 7.

NO

>> GO TO 1.

7.

PERFORM SELF-DIAGNOSIS (4WAS FRONT CONTROL UNIT)

With CONSULT-III

Perform 4WAS front control unit self-diagnosis.

Is any error system detected?

YES

>> Check the error system.

NO

>> GO TO 8.

8.

ERASE ERROR HISTORY

With CONSULT-III

Erase the memory of 4WAS front control unit and 4WAS main control unit self-diagnosis result.

>> END

4WAS STR ANG

: 

−

3.5 – 3.5 deg

STC-32

< FUNCTION DIAGNOSIS >

[WITH 4WAS]

4WAS SYSTEM

FUNCTION DIAGNOSIS

4WAS SYSTEM

System Diagram

INFOID:0000000001666296

CONTROL DIAGRAM

 CROSS-SECTIONAL VIEW

4WAS Front Actuator

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JSGIA0059JP

1.

Front wheel steering angle sensor

2.

4WAS front lock solenoid valve (lock 
structure)

3.

4WAS front motor

4.

Gear shaft

4WAS SYSTEM

STC-33

< FUNCTION DIAGNOSIS >

[WITH 4WAS]

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4WAS Rear Actuator

System Description

INFOID:0000000001666297

DESCRIPTION

• 4WAS system consists of two control units (4WAS front control unit and 4WAS main control unit) and 4WAS

rear actuator components.

• 4WAS main control unit calculates front wheel and rear wheel angles via CAN communication based on the

information of the steering angle sensor signal and vehicle speed signal.

• 4WAS main control unit controls 4WAS rear actuator according to the value calculated in 4WAS main control

unit.

• It transmits the value that is calculated by 4WAS main control unit to 4WAS front control unit via 4WAS com-

munication line (exclusive line of 4WAS system). 4WAS front control unit controls 4WAS front actuator
based on the received demand.

• Self-diagnosis can be performed with CONSULT-III at each control unit to another (4WAS front control unit

and 4WAS main control unit).

• It transmits/receives each signal from the following control unit via CAN communication line.

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

Operation Description

• The following performance is gained by controlling the best front wheel steering angle and the rear wheel

steering angle.

- The desirable vehicle movement is gained toward the driver's steering angle operation (steering angle).

SGIA1577E

1.

Rod

2.

Offset shaft

3.

Gear housing assembly

4.

4WAS rear motor

5.

Motor shaft

6.

Rear wheel steering angle sensor

7.

HRH gear

Component parts

Function

Steering angle sensor

It mainly transmits the following signals to 4WAS main control unit with CAN communication.
• Steering angle sensor signal

ABS actuator and electronic unit (con-
trol unit)

It mainly transmits the following signals to 4WAS main control unit with CAN communication.
• Vehicle speed signal

ECM

It mainly transmits the following signals to 4WAS main control unit with CAN communication.
• Engine speed signal

Combination meter

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

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 optimum front wheel angle

by minimum steering wheel operation (steering angle).

When Driving at Middle Speed

• Increase the front steering angle while controlling to turn the rear

wheel steering angle to the same steering angle side of steering
wheel operation (steering angle). these operations make response
better for vehicle yaw rate/lateral acceleration and also decrease
the angle of sideslip.

When Driving at High Speed

• Decrease the front wheel steering angle while controlling to turn

the rear wheel steering angle to the same steering angle side of
steering wheel operation (steering angle). these operations make
car response better and vehicle stability higher.

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.

JSGIA0080GB

JSGIA0050GB

JSGIA0082GB

JSGIA0084GB