Infiniti FX35, FX50 (S51). Manual - part 1771

UNBALANCE STEERING WHEEL TURNING FORCE (TORQUE VARIATION)

STC-25

< SYMPTOM DIAGNOSIS >

[WITHOUT REAR ACTIVE STEER]

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SYMPTOM DIAGNOSIS

UNBALANCE STEERING WHEEL TURNING FORCE (TORQUE VARIA-
TION)

Description

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• Hard steering when fully turning the steering wheel.
• Light steering when driving at a high speed.

Diagnosis Procedure

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1.

CHECK SYSTEM FOR POWER SUPPLY AND GROUND

Perform trouble diagnosis for power supply and ground. Refer to 

STC-8, "Diagnosis Procedure"

.

Is the inspection result normal?

YES

>> GO TO 2.

NO

>> Repair or replace damaged parts.

2.

CHECK SYSTEM FOR VEHICLE SPEED SIGNAL

Perform trouble diagnosis for vehicle speed signal. Refer to 

STC-14, "Diagnosis Procedure"

.

Is the inspection result normal?

YES

>> GO TO 3.

NO

>> Repair or replace damaged parts.

3.

CHECK SYSTEM FOR ENGINE SPEED SIGNAL

Perform trouble diagnosis for engine speed signal. Refer to 

STC-11, "Diagnosis Procedure"

.

Is the inspection result normal?

YES

>> GO TO 4.

NO

>> Repair or replace damaged parts.

4.

CHECK SYSTEM FOR POWER STEERING SOLENOID VALVE

Perform trouble diagnosis for power steering solenoid valve. Refer to 

STC-9, "Diagnosis Procedure"

.

Is the inspection result normal?

YES

>> Perform the symptom diagnosis for the steering system. Refer to 

ST-3, "NVH Troubleshooting

Chart"

.

NO

>> Repair or replace damaged parts.

STC-26

< PRECAUTION >

[WITHOUT REAR ACTIVE STEER]

PRECAUTIONS

PRECAUTION

PRECAUTIONS

Precaution for Supplemental Restraint System (SRS) "AIR BAG" and "SEAT BELT 
PRE-TENSIONER"

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The Supplemental Restraint System such as “AIR BAG” and “SEAT BELT PRE-TENSIONER”, used along
with a front seat belt, helps to reduce the risk or severity of injury to the driver and front passenger for certain
types of collision. This system includes seat belt switch inputs and dual stage front air bag modules. The SRS
system uses the seat belt switches to determine the front air bag deployment, and may only deploy one front
air bag, depending on the severity of a collision and whether the front occupants are belted or unbelted.
Information necessary to service the system safely is included in the “SRS AIR BAG” and “SEAT BELT” of this
Service Manual.

WARNING:

• To avoid rendering the SRS inoperative, which could increase the risk of personal injury or death in

the event of a collision which would result in air bag inflation, all maintenance must be performed by
an authorized NISSAN/INFINITI dealer.

• Improper maintenance, including incorrect removal and installation of the SRS, can lead to personal

injury caused by unintentional activation of the system. For removal of Spiral Cable and Air Bag
Module, see the “SRS AIR BAG”.

• Do not use electrical test equipment on any circuit related to the SRS unless instructed to in this

Service Manual. SRS wiring harnesses can be identified by yellow and/or orange harnesses or har-
ness connectors.

PRECAUTIONS WHEN USING POWER TOOLS (AIR OR ELECTRIC) AND HAMMERS

WARNING:

• When working near the Air Bag Diagnosis Sensor Unit or other Air Bag System sensors with the

ignition ON or engine running, DO NOT use air or electric power tools or strike near the sensor(s)
with a hammer. Heavy vibration could activate the sensor(s) and deploy the air bag(s), possibly
causing serious injury.

• When using air or electric power tools or hammers, always switch the ignition OFF, disconnect the

battery, and wait at least 3 minutes before performing any service.

Precaution Necessary for Steering Wheel Rotation after Battery Disconnect

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NOTE:
• Before removing and installing any control units, first turn the push-button ignition switch to the LOCK posi-

tion, then disconnect both battery cables.

• After finishing work, confirm that all control unit connectors are connected properly, then re-connect both

battery cables.

This vehicle is equipped with a push-button ignition switch and a steering lock unit.
If the battery is disconnected or discharged, the steering wheel will lock and cannot be turned.
If turning the steering wheel is required with the battery disconnected or discharged, follow the procedure
below before starting the repair operation.

OPERATION PROCEDURE

1.

Connect both battery cables.
NOTE:
Supply power using jumper cables if battery is discharged.

2.

Turn the push-button ignition switch to ACC position.
(At this time, the steering lock will be released.)

3.

Disconnect both battery cables. The steering lock will remain released with both battery cables discon-
nected and the steering wheel can be turned.

4.

Perform the necessary repair operation.

5.

When the repair work is completed, re-connect both battery cables. With the brake pedal released, turn
the push-button ignition switch from ACC position to ON position, then to LOCK position. (The steering
wheel will lock when the push-button ignition switch is turned to LOCK position.)

POWER STEERING CONTROL UNIT

STC-27

< REMOVAL AND INSTALLATION >

[WITHOUT REAR ACTIVE STEER]

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REMOVAL AND INSTALLATION

POWER STEERING CONTROL UNIT

Removal and Installation

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REMOVAL

1.

Remove instrument lower cover RH. Refer to 

IP-11, "Exploded View"

.

2.

Remove instrument lower panel RH. Refer to 

IP-11, "Exploded View"

.

3.

Remove power steering control unit.

4.

Disconnect power steering control unit connector.

INSTALLATION

Install in the reverse order of removal.

STC-28

< BASIC INSPECTION >

[WITH REAR ACTIVE STEER]

DIAGNOSIS AND REPAIR WORKFLOW

BASIC INSPECTION

DIAGNOSIS AND REPAIR WORKFLOW

Work Flow

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DETAILED FLOW

1.

INTERVIEW THE CUSTOMER

It is also important to clarify customer complaints before inspection. First of all, reproduce symptoms, and
understand them fully. Ask the customer about his/her complaints carefully. In some cases, it is necessary to
check symptoms by driving the customer with the customer.

CAUTION:

Customers are not professional. It is dangerous to make an easy guess like “maybe the customer
means that...,” or “maybe the customer mentions this symptom”.

>> GO TO 2.

2.

CHECK SYMPTOM

Reproduce symptoms indicated by the customer, based on information obtained from the interview with the
customer. In addition, check if the symptoms are caused by the Fail-safe function and the protective function.
Refer to 

STC-100, "Fail-Safe"

.

CAUTION:

If the symptoms are normal operation, check each part thoroughly and gain the understanding from
the customer, explaining that the symptoms are not malfunction.

>> GO TO 3.

3.

CHECK CURRENT STATE

Start the engine.

CAUTION:

Stop the vehicle.

Does RAS warning lamp turn ON?

YES

>> GO TO 4.

NO

>> GO TO 8.

4.

PERFORM SELF-DIAGNOSIS

With CONSULT-III

Perform “4WAS(MAIN)/RAS/HICAS” self-diagnosis.

Is any DTC detected?

YES

>> Record or print the self-diagnosis results and go to 5.

NO

>> GO TO 8.

5.

RECHECK SYMPTOM

With CONSULT-III

1.

Turn the ignition switch OFF and wait for 10 seconds or more.

2.

Record the values of “DATA MONITOR” for each DTC detected by self-diagnosis.

3.

Record the values of “FREEZE FRAME DATA” for each DTC detected by self-diagnosis.

4.

Erase the memory of self-diagnosis results (history) of “4WAS(MAIN)/RAS/HICAS”.

CAUTION:

• When replacing the RAS control unit according to the self-diagnosis, replace it without erasing

self-diagnosis results (history).

• When erasing the memory of the self-diagnosis results (history), print or record all the values of

“DATA MONITOR” for each DTC with CONSULT-III to erase the memory of the self-diagnosis
result (history).

5.

Perform “DTC CONFIRMATION PROCEDURE” for each malfunction.
NOTE: