Nissan March K13. Manual - part 639

STEERING WHEEL TURNING FORCE IS HEAVY OR LIGHT

STC-31

< SYMPTOM DIAGNOSIS >

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STEERING WHEEL TURNING FORCE IS HEAVY OR LIGHT

Description

INFOID:0000000005912749

Steering wheel turning force is heavy or light.

Diagnosis Procedure

INFOID:0000000005912750

1.

CHECK THE ILLUMINATION OF THE EPS WARNING LAMP

Check that the EPS warning lamp turns ON when ignition switch turns ON. Then, EPS warning lamp turns
OFF after the engine is started.
Is the inspection result normal?

YES

>> GO TO 4.

NO

>> GO TO 2.

2.

PERFORM SELF-DIAGNOSIS

With CONSULT-III

1.

Turn the ignition switch OFF to ON.

2.

Perform “EPS” self-diagnosis.

Is any DTC detected?

YES

>> Check the DTC. Refer to 

STC-12, "DTC Index"

. 

NO

>> GO TO 3.

3.

CHECK EPS CONTROL UNIT SIGNAL

With CONSULT-III

1.

Start the engine.

CAUTION:

Stop the vehicle.

2.

Turn steering wheel from full left stop to full right stop.

3.

Select “DATA MONITOR” of “EPS” and select “TORQUE SENSOR”.

4.

Perform the torque sensor inspection.

Is the inspection result normal?

YES

>> GO TO 5.

NO

>> GO TO 4.

4.

CHECK EPS MOTOR

Perform the trouble diagnosis of EPS motor. Refer to 

STC-23, "Diagnosis Procedure"

.

Is the inspection result normal?

YES

>> GO TO 5.

NO

>> Repair or replace the specific malfunctioning part.

5.

CHECK STEERING WHEEL TURNING FORCE

Check the steering wheel turning force. Refer to 

ST-8, "Inspection"

.

Is the inspection result normal?

YES

>> INSPECTION END

NO

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

ST-8, "Inspection"

.

Monitor item 

Condition

Display value

TORQUE SENSOR

Steering wheel: Not steer-
ing (There is no steering 
force)

Approx. 0 Nm

Steering wheel: Right turn

Positive value (Nm)

Steering wheel: Left turn

Negative value (Nm)

STC-32

< SYMPTOM DIAGNOSIS >

UNBALANCE STEERING WHEEL TURNING FORCE AND RETURN BETWEEN 

RIGHT AND LEFT

UNBALANCE STEERING WHEEL TURNING FORCE AND RETURN BE-
TWEEN RIGHT AND LEFT

Description

INFOID:0000000005912751

Unbalance steering wheel turning force and return between right and left.

Diagnosis Procedure

INFOID:0000000005912752

1.

CHECK THE ILLUMINATION OF THE EPS WARNING LAMP

Check that the EPS warning lamp turns ON when ignition switch turns ON. Then, EPS warning lamp turns
OFF after the engine is started.
Is the inspection result normal?

YES

>> GO TO 2.

NO

>> Refer to 

STC-30, "Diagnosis Procedure"

.

2.

CHECK WHEEL ALIGNMENT

1.

Check the wheel alignment. Refer to 

FSU-7, "Inspection"

.

2.

Perform “EPS” self-diagnosis.

Is the inspection result normal?

YES

>> GO TO 3.

NO

>> Adjustment of wheel alignment. Refer to 

FSU-7, "Inspection"

.

3.

CHECK EPS CONTROL UNIT SIGNAL

With CONSULT-III

1.

Start the engine.

CAUTION:

Stop the vehicle.

2.

Turn steering wheel from full left stop to full right stop.

3.

Select “DATA MONITOR” of “EPS” and select “TORQUE SENSOR”.

4.

Perform the torque sensor inspection.

Is the inspection result normal?

YES

>> GO TO 5.

NO

>> GO TO 4.

4.

CHECK EPS MOTOR

Perform the trouble diagnosis of EPS motor. Refer to 

STC-23, "Diagnosis Procedure"

.

Is the inspection result normal?

YES

>> GO TO 5.

NO

>> Repair or replace the specific malfunctioning part.

5.

CHECK STEERING WHEEL TURNING FORCE

Check the steering wheel turning force. Refer to 

ST-8, "Inspection"

.

Is the inspection result normal?

YES

>> INSPECTION END

NO

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

ST-8, "Inspection"

.

Monitor item 

Condition

Display value

TORQUE SENSOR

Steering wheel: Not steer-
ing (There is no steering 
force)

Approx. 0 Nm

Steering wheel: Right turn

Positive value (Nm)

Steering wheel: Left turn

Negative value (Nm)

UNBALANCE STEERING WHEEL TURNING FORCE (TORQUE VARIATION)

STC-33

< SYMPTOM DIAGNOSIS >

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UNBALANCE STEERING WHEEL TURNING FORCE (TORQUE VARIA-
TION)

Description

INFOID:0000000005912753

Unbalance steering wheel turning force (torque variation).

Diagnosis Procedure

INFOID:0000000005912754

1.

CHECK THE ILLUMINATION OF THE EPS WARNING LAMP

Check that the EPS warning lamp turns ON when ignition switch turns ON. Then, EPS warning lamp turns
OFF after the engine is started.
Is the inspection result normal?

YES

>> GO TO 2.

NO

>> Refer to 

STC-30, "Diagnosis Procedure"

.

2.

CHECK STEERING COLUMN AND STEERING GEAR

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

ST-11, "Exploded View"

.

• Steering gear assembly. Refer to 

ST-14, "Exploded View"

.

Is the inspection result normal?

YES

>> GO TO 3.

NO

>> Repair or replace the specific malfunctioning part.

3.

CHECK EPS CONTROL UNIT SIGNAL

With CONSULT-III

1.

Start the engine.

CAUTION:

Stop the vehicle.

2.

Turn steering wheel from full left stop to full right stop.

3.

Select “DATA MONITOR” of “EPS” and select “TORQUE SENSOR”.

4.

Perform the torque sensor inspection.

Is the inspection result normal?

YES

>> GO TO 5.

NO

>> GO TO 4.

4.

CHECK EPS MOTOR

Perform the trouble diagnosis of EPS motor. Refer to 

STC-23, "Diagnosis Procedure"

.

Is the inspection result normal?

YES

>> GO TO 5.

NO

>> Repair or replace the specific malfunctioning part.

5.

CHECK STEERING WHEEL TURNING FORCE

Check the steering wheel turning force. Refer to 

ST-8, "Inspection"

.

Is the inspection result normal?

YES

>> INSPECTION END

NO

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

ST-8, "Inspection"

.

Monitor item 

Condition

Display value

TORQUE SENSOR

Steering wheel: Not steer-
ing (There is no steering 
force)

Approx. 0 Nm

Steering wheel: Right turn

Positive value (Nm)

Steering wheel: Left turn

Negative value (Nm)

STC-34

< REMOVAL AND INSTALLATION >

EPS CONTROL UNIT

REMOVAL AND INSTALLATION

EPS CONTROL UNIT

Exploded View

INFOID:0000000005912755

Removal and Installation

INFOID:0000000005912756

REMOVAL

CAUTION:

• Disconnect battery negative terminal before starting operations.
• Never shock EPS control unit, e.g. drop or hit.
• Never get EPS control unit wet with water or other liquid. Also, do not give EPS control unit a radical

temperature change to avoid getting water drops. 

• Never disassemble or remodel EPS control unit, EPS motor, torque sensor, harness and connectors.

1.

Remove instrument lower panel LH. Refer to 

IP-12, "Exploded View"

.

2.

Disconnect EPS control unit connectors.

CAUTION:

Hold and pull the connector housing, not pulling harness, when disconnecting connectors. Also,
do not grip, collapse or apply excessive force to the connector.

3.

Remove EPS control unit from steering column assembly.

INSTALLATION

Note the following, and install in the reverse order of removal.
• Check that harness is not damaged when installing EPS control unit. Also, check that EPS control unit is

installed without trapping harness of foreign materials.

• After installing steering column assembly, perform self-diagnosis with CONSULT-III to ensure correct opera-

tion. Refer to 

STC-9, "CONSULT-III Function"

.

1.

Steering column assembly

2.

Bracket

3.

EPS control unit

Refer to 

GI-4, "Components"

 for symbols in the figure.

JPGIB0004GB