Nissan Quest E52. Instruction — part 1187

UNBALANCE STEERING WHEEL TURNING FORCE (TORQUE VARIATION)

STC-37

< SYMPTOM DIAGNOSIS >

STC

UNBALANCE STEERING WHEEL TURNING FORCE (TORQUE VARIA-
TION)

Diagnosis Procedure

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PERFORM SELF-DIAGNOSIS

With CONSULT

Perform “EPS” self-diagnosis.
Is a malfunctioning system displayed?

YES

>> Check malfunctioning system. Refer to

STC-14, "DTC Index"

>> GO TO 2.

CHECK THE POWER STEERING CONTROL MODULE SIGNAL (1)

With CONSULT

Start the engine.

CAUTION:

Never drive the vehicle.

Turn the steering wheel until it stops.

Select “MTR ASSIST” in “DATA MONITOR” in “EPS”.

Is the display value “100%”?

YES

>> GO TO 4.

>> GO TO 3.

CHECK THE POWER STEERING CONTROL MODULE SIGNAL (2)

With CONSULT

Select “C/U TEMP” and “C/U TEMP A” in “DATA MONITOR” in “EPS”.

Stop the system until the DATA MONITOR display value drops to “90

C (194

F)” or less.

Check whether symptom continues.

Did symptom continue?

YES

>> GO TO 4.

>> This occurs because the protection function lowers the assist force. It is not a system malfunction.

INSPECTION END

CHECK THE POWER STEERING CONTROL MODULE SIGNAL (3)

With CONSULT

Turn the steering wheel to the straight-ahead position. (There is no steering force)

Select “BATTERY VOLT” in “DATA MONITOR” in “EPS”.

Is the display value “10.5 V” or more?

YES

>> GO TO 5.

>> Check the battery power system. Refer to

STC-21, "Diagnosis Procedure"

CHECK THE POWER STEERING CONTROL MODULE SIGNAL (4)

With CONSULT

Select in “ESTM VHCL SPD” in “DATA MONITOR” in “EPS”.

*: This may not agree with the speedometer indication immediately after the ignition switch is turned ON. This
is not a malfunction.
Is the check result normal?

YES

>> GO TO 6.

Monitor item

Test condition

Display value

ESTM VHCL SPD

When stopped

0.00 km/h or mph

While driving

Approximately equal to the in-

dication on speedometer

(Inside of

10%)

STC-38

< SYMPTOM DIAGNOSIS >

UNBALANCE STEERING WHEEL TURNING FORCE (TORQUE VARIATION)

>> Check the combination meter, ABS actuator and electric unit (control unit). Refer to

MWI-35,

"CONSULT Function"

and

BRC-30, "CONSULT Function"

CHECK THE POWER STEERING CONTROL MODULE SIGNAL (5)

With CONSULT

Select “STR ANG SPD” in “DATA MONITOR” in “EPS”.

Is the check result normal?

YES

>> GO TO 7.

>> Check the steering angle sensor. Refer to

STC-20, "Diagnosis Procedure"

CHECK THE POWER STEERING CONTROL MODULE SIGNAL (6)

With CONSULT

Select “ENGINE STATUS” in “DATA MONITOR” in “EPS”.
Is the display value “RUN”?

YES

>> GO TO 8.

>> Check the ECM. Refer to

EC-69, "CONSULT Function"

CHECK STEERING COLUMN AND STEERING GEAR

Check the steering column assembly and steering gear assembly.
• Steering column assembly. Refer to

ST-13, "Exploded View"

• Steering gear assembly. Refer to

ST-20, "Exploded View"

Is the inspection result normal?

YES

>> GO TO 9.

>> Repair or replace error-detected parts.

CHECK STEERING WHEEL TURNING FORCE

Check the steering wheel turning force. Refer to

ST-6, "Inspection"

Is the inspection result normal?

YES

>> INSPECTION END

>> Check the steering wheel turning force for mechanical malfunction. Refer to

ST-30, "Inspection"

Monitor item

Test condition

Display value

STR ANG SPD

The steering wheel is not
steered.

Approx. 0.0 deg/s

The steering wheel is steered.

Displays steering angle speed
(deg/s)

POWER STEERING CONTROL MODULE

STC-39

< REMOVAL AND INSTALLATION >

STC

REMOVAL AND INSTALLATION

POWER STEERING CONTROL MODULE

Removal and Installation

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CAUTION:

Disconnect battery negative terminal before starting operations.
Never remove power steering control module from steering oil pump assembly. When replacing power steer-
ing control module, replace steering oil pump assembly. Refer to

ST-13, "Removal and Installation"

STR-1

ENGINE