Infiniti QX56 (Z62). Manual - part 1265

STC-12

< WIRING DIAGRAM >

ELECTRONICALLY CONTROLLED POWER STEERING SYSTEM

JCGWM0394GB

DIAGNOSIS AND REPAIR WORK FLOW

STC-13

< BASIC INSPECTION >

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BASIC INSPECTION

DIAGNOSIS AND REPAIR WORK FLOW

Work Flow

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DETAILED FLOW

1.

COLLECT THE INFORMATION FROM THE CUSTOMER

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

1.

Power steering fluid leakage and check the power steering fluid level. Refer to 

ST-30, "Inspection"

.

2.

Check the drive belt tension. Refer to 

EM-20, "Checking"

.

3.

Check the power steering gear for damages, cracks and fluid leakage. Refer to 

ST-46, "Inspection"

.

4.

Check the relief oil pressure. Refer to 

ST-52, "Inspection"

.

>> GO TO 3.

3.

DIAGNOSIS CHART BY SYMPTOM

Perform the diagnosis by symptom. Refer to 

STC-22, "Diagnosis Procedure"

.

>> GO TO 4.

4.

FINAL CHECK

Check the input/output standard values for the power steering control unit.
Are the power steering control unit input/output values within standard ranges respectively?

YES

>> INSPECTION END

NO

>> GO TO 2.

STC-14

< DTC/CIRCUIT DIAGNOSIS >

POWER SUPPLY AND GROUND CIRCUIT

DTC/CIRCUIT DIAGNOSIS

POWER SUPPLY AND GROUND CIRCUIT

Diagnosis Procedure

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1.

CHECK POWER SUPPLY (1)

1.

Turn the ignition switch OFF.

2.

Disconnect power steering control unit harness connector.

3.

Check the voltage between power steering control unit harness connector and ground.

4.

Turn the ignition switch ON.

CAUTION:

Never start the engine.

5.

Check the voltage between power steering control unit harness connector and ground.

Is the inspection result normal?

YES

>> GO TO 3.

NO

>> GO TO 2.

2.

CHECK POWER SUPPLY (2)

1.

Turn the ignition switch OFF.

2.

Check 10A fuse (#3).

3.

Disconnect fuse block (J/B) harness connector.

4.

Check the continuity between power steering control unit harness connector and fuse block (J/B) harness
connector.

5.

Check the continuity between power steering control unit harness connector and ground.

Is the inspection result normal?

YES

>> Perform trouble diagnosis for ignition power supply circuit. Refer to 

PG-89, "Wiring Diagram -

IGNITION POWER SUPPLY -"

.

NO

>> Repair or replace damaged parts.

3.

CHECK GROUND CIRCUIT

1.

Turn the ignition switch OFF.

2.

Check the continuity between power steering control unit harness connector and ground.

Power steering control unit

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Voltage

Connector

Terminal

M108

3 Ground

0 

V

Power steering control unit

—

Voltage

Connector

Terminal

M108

3 Ground

Battery 

voltage

Power steering control unit

Fuse block (J/B)

Continuity

Connector

Terminal

Connector

Terminal

M108

3

M1

2A

Existed

Power steering control unit

—

Continuity

Connector

Terminal

M108

3

Ground

Not existed

POWER SUPPLY AND GROUND CIRCUIT

STC-15

< DTC/CIRCUIT DIAGNOSIS >

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Is the inspection result normal?

YES

>> GO TO 4.

NO

>> Repair or replace error-detected parts.

4.

CHECK TERMINALS AND HARNESS CONNECTORS

Check the power steering control unit pin terminals for damage or loose connection with harness connector.

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> Repair or replace error-detected parts.

Power steering control unit

—

Continuity

Connector

Terminal

M108

6 Ground

Existed