Nissan Qashqai (2007-2010). Manual — part 751

DIAGNOSIS AND REPAIR WORKFLOW

STC-3

< BASIC INSPECTION >

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BASIC INSPECTION

DIAGNOSIS AND REPAIR WORKFLOW

Work Flow

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DETAIED FLOW

1.

COLLECT THE INFORMATION FROM THE CUSTOMER

Get the detailed information from the customer about the symptom (the condition and the environment when
the incident/malfunction occurred) using the diagnosis worksheet.

>> GO TO 2.

2.

PERFORM THE SELF-DIAGNOSIS

Check the DTC display with the self-diagnosis function. Refer to

STC-7, "CONSULT-III Function (EPS)"

.

Is there any DTC displayed?

YES

>> GO TO 3.

NO

>> GO TO 4.

3.

PERFORM THE SYSTEM DIAGNOSIS

Perform the diagnosis applicable to the displayed DTC. Refer to

STC-22, "DTC No. Index"

.

>> GO TO 6.

4.

CHECK THE WARNING LAMP FOR ILLUMINATION

Check that the warning lamp illuminate.
Is ON/OFF timing normal?

YES

>> GO TO 5.

NO

>> GO TO 2.

5.

PERFORM THE DIAGNOSIS BY SYMPTOM

Perform the diagnosis applicable to the symptom.

>> GO TO 6.

6.

REPAIR OR REPLACE THE MALFUNCTIONING PARTS

Repair or replace the specified malfunctioning parts.

>> GO TO 7.

7.

FINAL CHECK

Perform the self-diagnosis again, and check that the malfunction is repaired completely. After checking, erase
the self-diagnosis memory. Refer to

STC-7, "CONSULT-III Function (EPS)"

.

Is no other DTC present and the repair completed?

YES

>> INSPECTION END

NO

>> GO TO 3.

STC-4

< FUNCTION DIAGNOSIS >

EPS SYSTEM

FUNCTION DIAGNOSIS

EPS SYSTEM

System Diagram

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System Description

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• EPS control unit performs an arithmetical operation on data, such as steering wheel turning force (sensor

signal) from the torque sensor, vehicle speed signal, etc. Then it generates an optimum assist torque to the
EPS motor according to the driving condition.

• EPS control unit decreases the output to EPS motor while extremely using the power steering function (e.g.,

full steering) for protecting EPS motor and EPS control unit (Protect overload status). While activating pro-
tect overload status, the assist torque gradually decreases, and the steering wheel turning force becomes
heavy. The normal assist torque reactivates by not steering.

• In case of an error in the electrical system, the fail-safe function stops output signals to the EPS motor. Then

the previous state is changed to the manual steering state.

• Self-diagnosis can be done with CONSULT-III.
• EPS control unit will decrease assistance under 2 conditions.
- Extensive steering at low speed will cause the ECU and MOTOR to heat up, once temperature reaches crit-

ical point ECU will reduce current to reduce heat up. System will recover as temperature lowers (reduced or
no assistance).

- Holding steering on rack-end (full lock) for 1 second will cause the system to engage rack-end protection.

This reduces assistance down to 40% in order to prevent heat up. Assistance is immediately returned to
100% when steering released or turned away from rack-end.

Component Parts Location

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JSGIA0159GB

EPS SYSTEM

STC-5

< FUNCTION DIAGNOSIS >

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LHD models

JSGIA0148ZZ

1.

EPS warning lamp

2.

EPS control unit

3.

EPS motor

4.

Torque sensor

5.

Reduction gear

A.

Combination meter

B.

Steering column assembly

STC-6

< FUNCTION DIAGNOSIS >

EPS SYSTEM

RHD models

Component Description

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JSGIA0147ZZ

1.

EPS warning lamp

2.

EPS control unit

3.

EPS motor

4.

Torque sensor

5.

Reduction gear

A.

Combination meter

B.

Steering column assembly

Components parts

Reference

EPS control unit

STC-13, "Description"

EPS motor

STC-11, "Description"

Torque sensor

STC-10, "Description"

Reduction gear

Reduction gear increases the assist torque provided from EPS
motor with worm gears, and outputs to the column shaft.

EPS warning lamp

Turn on when a malfunction occurs in the EPS system, and tells
the driver the malfunction.