Infiniti QX56 (JA60). Manual - part 271

DIAGNOSIS AND REPAIR WORKFLOW

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< BASIC INSPECTION >

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>> GO TO 4

4.

SYMPTOM

Check for symptoms.  Refer to 

DLN-102, "Symptom Table"

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>> GO TO 5

5.

MALFUNCTIONING PARTS

Repair or replace the applicable parts.

>> GO TO 6

6.

SYSTEM OPERATION

Check system operation.

>> GO TO 7

7.

SELF-DIAGNOSIS

Perform self-diagnosis.
Are any DTC's displayed?

YES

>> GO TO 5

NO

>> Inspection End

Preliminary Check

INFOID:0000000005148769

TRANSFER FLUID CHECK

Check for leaks and fluid level. Refer to 

DLN-129, "Inspection"

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PREPARATION FOR ROAD TEST

The purpose of the test is to determine overall performance of trans-

fer case and analyze causes of malfunctions.

When a malfunction is found in any part of transfer, perform the road

test to locate the malfunction area and repair the malfunction parts.

The road test consists of the following three parts.

1. CHECK BEFORE ENGINE IS STARTED

2. CHECK AT IDLE

3. CRUISE TEST

CHECK BEFORE ENGINE IS STARTED

1.

CHECK 4WD SHIFT INDICATOR LAMP

1. Park vehicle on flat surface.

2. Turn ignition switch to OFF position.

3. Move A/T selector lever to P position.

4. Set 4WD shift switch to 2WD position.

5. Turn ignition switch to ON position. (Do not start engine.)
Does 4WD shift indicator lamp turn ON for approximately 1 second?

YES

>> GO TO 2.

NO

>> GO TO 

DLN-103, "Diagnosis Procedure"

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2.

CHECK 4WD WARNING LAMP

1. Turn ignition switch to OFF position.

2. Move A/T selector lever to P position.

3. Set 4WD shift switch to 2WD position.

4. Turn ignition switch to ON position. (Do not start engine.)

SMT089D

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< BASIC INSPECTION >

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DIAGNOSIS AND REPAIR WORKFLOW

Does 4WD warning lamp turn ON?

YES

>> GO TO CHECK AT IDLE.

NO

>> GO TO 

DLN-105, "Diagnosis Procedure"

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CHECK AT IDLE

1.

CHECK 4WD SHIFT INDICATOR LAMP

1. Park vehicle on flat surface and engage the parking brake.

2. Turn ignition switch to OFF position.

3. Move A/T selector lever to P position.

4. Set 4WD shift switch to 2WD position.

5. Start engine.
Does 4WD shift indicator lamp turn ON?

YES

>> GO TO 3.

NO

>> GO TO 2.

2.

CHECK 4WD WARNING LAMP 

Check 4WD warning lamp state.
Is 4WD warning lamp turned ON?

YES

>> Perform the self-diagnosis. Refer to  

DLN-18, "CONSULT-III Function (ALL MODE AWD/4WD)"

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NO

>> Refer to 

DLN-107, "Diagnosis Procedure"

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3.

CHECK 4WD SHIFT INDICATOR AND 4LO INDICATOR OPERATION

1. Brake pedal depressed.

2. Move A/T selector lever to N position.

3. Set 4WD shift switch to 2WD, AUTO, 4H, 4LO, 4H, AUTO and

2WD in order. (Stay at each switch position for at least 1 sec-

ond.)

Do 4WD shift indicator and 4LO indicator lamps change properly?

Does buzzer sound?

YES

>> GO TO CRUISE TEST.

NO

>> GO TO 

DLN-107, "Diagnosis Procedure"

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CRUISE TEST

1.

CHECK INPUT SIGNAL

1. Warm up engine to normal operating temperature.

2. Park vehicle on flat surface.

3. Move A/T selector lever to P position.

4. Set 4WD shift switch to AUTO position.

5. Start engine.

6. Drive vehicle for at least 30 seconds at a speed higher than 20 km/h (12 MPH).
Is 4WD warning lamp turned ON?

On steady>>Perform the self-diagnosis. Refer to  

DLN-18, "CONSULT-III Function (ALL MODE AWD/4WD)"

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WDIA0136E

DIAGNOSIS AND REPAIR WORKFLOW

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Flash rapidly>>Refer to 

DLN-112, "Diagnosis Procedure"

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Flash slowly>>Refer to 

DLN-113, "Diagnosis Procedure"

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NO

>> GO TO 2.

2.

CHECK TIGHT CORNER BRAKING SYMPTOM (1)

1. Set 4WD shift switch to AUTO position.

2. Drive vehicle at speed lower than 20 km/h (12 MPH) with steering wheel fully turned.
Does tight corner braking symptom occur?

YES

>> GO TO 

DLN-114, "Diagnosis Procedure"

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NO

>> GO TO 3.

3.

CHECK TIGHT CORNER BRAKING SYMPTOM (2)

1. Set 4WD shift switch to 4HI position.

2. Drive vehicle at speed lower than 20 km/h (12 MPH) with steering wheel fully turned.
Does tight corner braking symptom occur?

YES

>> Inspection End.

NO

>> GO TO 

DLN-118, "Diagnosis Procedure"

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< FUNCTION DIAGNOSIS >

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4WD SYSTEM

FUNCTION DIAGNOSIS

4WD SYSTEM

System Diagram

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COMPONENT DESCRIPTION

WDIA0164E

Components

Function

Transfer control unit

Controls transfer control device, control valves and shifts between 2WD/4WD and 4H/4LO.

Transfer control device

Integrates actuator motor and actuator position switch.

2-4WD shift solenoid valve

Controls oil pressure and allows shifting between 2WD and 4WD.

Clutch pressure solenoid valve

Controls oil pressure and distributes torque between front and rear tires.

Line pressure switch

Detects line pressure.

Clutch pressure switch

Detects clutch pressure.

Transfer fluid temperature sensor Detects transfer fluid temperature.

Actuator motor

Moves shift rods when signaled by transfer control unit.

Actuator position switch

Detects actuator motor position.

Wait detection switch

Detects whether or not 4WD lock gear is locked.

4LO switch

Detects if transfer case is in 4LO.

ATP switch

Detects if transfer case is in neutral.

4WD shift switch

Allows driver to select from 2WD/4WD, 4H/4LO and AUTO.

4WD warning lamp

• Illuminates if malfunction is detected in 4WD system.
• Flashes (1 flash / 2 seconds) if large difference in diameter of front and rear tires.
• Flashes (2 flashes / 1 second) if high transfer fluid temperature is detected.

ATP warning lamp

Indicates that A/T parking mechanism does not operate when A/T selector lever is in P position 
because transfer case is in neutral.

4WD shift indicator lamp

Displays driving range selected by 4WD shift switch.

4LO indicator lamp

Displays 4LO range.