2005 INFINITI QX4 engine

TF-1
TRANSFER
D DRIVELINE/AXLE
CONTENTS
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SECTION TF
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TF
Revision: October 20052005 QX56 PRECAUTIONS .......................................................... 4
Precautions for Supplemental Restraint System
(SRS) “AIR BAG” and “SEAT BELT PRE-TEN-
SIONER” .................................................................. 4
Precautions for Transfer Assembly and Transfer
Control Unit Replacement ........................................ 4
METHOD FOR POSITION ADJUSTMENT ........... 4
Precautions .............................................................. 4
Service Notice .......................................................... 5
Wiring Diagrams and Trouble Diagnosis .................. 5
PREPARATION ........................................................... 6
Special Service Tools ............................................... 6
Commercial Service Tools ........................................ 9
NOISE, VIBRATION AND HARSHNESS (NVH)
TROUBLESHOOTING .............................................. 10
NVH Troubleshooting Chart ................................... 10
TRANSFER FLUID ....................................................11
Replacement ...........................................................11
DRAINING ............................................................11
FILLING ................................................................11
Inspection ................................................................11
FLUID LEAKAGE AND FLUID LEVEL .................11
ALL-MODE 4WD SYSTEM ...................................... 12
Cross-section View ................................................ 12
Power Transfer ....................................................... 13
POWER TRANSFER DIAGRAM ........................ 13
POWER TRANSFER FLOW ............................... 14
System Description ................................................ 15
CONTROL SYSTEM ........................................... 15
TRANSFER MOTOR .......................................... 16
WAIT DETECTION SWITCH .............................. 17
NEUTRAL-4LO SWITCH .................................... 17
ATP SWITCH ...................................................... 17
2-4WD SHIFT SOLENOID VALVE ...................... 17
CLUTCH PRESSURE SOLENOID VALVE ......... 17
LINE PRESSURE SWITCH ................................ 18
CLUTCH PRESSURE SWITCH .......................... 18
TRANSFER FLUID TEMPERATURE SENSOR ... 18
TRANSFER CONTROL UNIT ............................. 18
TRANSFER CONTROL DEVICE ........................ 184WD SHIFT SWITCH AND INDICATOR LAMP ... 18
4WD WARNING LAMP ....................................... 19
ATP WARNING LAMP ......................................... 19
System Diagram ..................................................... 19
COMPONENTS FUNCTION ............................... 20
CAN Communication .............................................. 20
SYSTEM DESCRIPTION .................................... 20
TROUBLE DIAGNOSIS ............................................ 21
How to Perform Trouble Diagnosis ......................... 21
BASIC CONCEPT ............................................... 21
Location of Electrical Parts ..................................... 22
Circuit Diagram ....................................................... 23
Wiring Diagram — T/F — ....................................... 24
Inspections Before Trouble Diagnosis .................... 32
TRANSFER FLUID CHECK ................................ 32
PREPARATION FOR ROAD TEST ..................... 32
CHECK BEFORE ENGINE IS STARTED ........... 32
CHECK AT IDLE .................................................. 32
CRUISE TEST ..................................................... 34
Trouble Diagnosis Chart for Symptoms .................. 34
Transfer Control Unit Input/Output Signal Refer-
ence Values ............................................................ 36
TRANSFER CONTROL UNIT INSPECTION
TABLE ................................................................. 36
CONSULT-II Function (ALL MODE AWD/4WD) ..... 44
FUNCTION .......................................................... 44
CONSULT-II SETTING PROCEDURE ................ 44
SELF-DIAG RESULT MODE ............................... 45
DATA MONITOR MODE ...................................... 47
WORK SUPPORT ............................................... 49
Self-diagnostic Procedure ...................................... 50
SELF-DIAGNOSTIC PROCEDURE (WITH
CONSULT-II) ....................................................... 50
SELF-DIAGNOSTIC PROCEDURE (WITHOUT
CONSULT-II) ....................................................... 50
ERASE SELF-DIAGNOSIS ................................. 53
TROUBLE DIAGNOSIS FOR SYSTEM .................... 54
Power Supply Circuit For Transfer Control Unit ...... 54
CONSULT-II REFERENCE VALUE IN DATA
MONITOR MODE ................................................ 54

TF-2Revision: October 20052005 QX56 TRANSFER CONTROL UNIT TERMINALS AND
REFERENCE VALUE .......................................... 54
DIAGNOSTIC PROCEDURE .............................. 55
COMPONENT INSPECTION .............................. 57
Transfer Control Unit .............................................. 57
DIAGNOSTIC PROCEDURE .............................. 57
Output Shaft Revolution Signal (TCM) ................... 58
DIAGNOSTIC PROCEDURE .............................. 58
Vehicle Speed Sensor (ABS) .................................. 58
DIAGNOSTIC PROCEDURE .............................. 58
Neutral-4LO Switch ................................................ 59
CONSULT-II REFERENCE VALUE IN DATA
MONITOR MODE ................................................ 59
TRANSFER CONTROL UNIT TERMINALS AND
REFERENCE VALUE .......................................... 59
DIAGNOSTIC PROCEDURE .............................. 60
COMPONENT INSPECTION .............................. 62
4WD Shift Switch .................................................... 62
CONSULT-II REFERENCE VALUE IN DATA
MONITOR MODE ................................................ 62
TRANSFER CONTROL UNIT TERMINALS AND
REFERENCE VALUE .......................................... 62
DIAGNOSTIC PROCEDURE .............................. 63
COMPONENT INSPECTION .............................. 66
Wait Detection Switch ............................................. 66
CONSULT-II REFERENCE VALUE IN DATA
MONITOR MODE ................................................ 66
TRANSFER CONTROL UNIT TERMINALS AND
REFERENCE VALUE .......................................... 66
DIAGNOSTIC PROCEDURE .............................. 67
COMPONENT INSPECTION .............................. 69
PNP Switch Signal (TCM) ...................................... 69
DIAGNOSTIC PROCEDURE .............................. 69
Actuator Motor ........................................................ 70
CONSULT-II REFERENCE VALUE IN DATA
MONITOR MODE ................................................ 70
TRANSFER CONTROL UNIT TERMINALS AND
REFERENCE VALUE .......................................... 70
DIAGNOSTIC PROCEDURE .............................. 71
COMPONENT INSPECTION .............................. 76
Actuator Position Switch ......................................... 77
CONSULT-II REFERENCE VALUE IN DATA
MONITOR MODE ................................................ 77
TRANSFER CONTROL UNIT TERMINALS AND
REFERENCE VALUE .......................................... 77
DIAGNOSTIC PROCEDURE .............................. 78
COMPONENT INSPECTION .............................. 80
Transfer Control Device .......................................... 81
CONSULT-II REFERENCE VALUE IN DATA
MONITOR MODE ................................................ 81
TRANSFER CONTROL UNIT TERMINALS AND
REFERENCE VALUE .......................................... 81
DIAGNOSTIC PROCEDURE .............................. 82
Engine Speed Signal (ECM) ................................... 85
DIAGNOSTIC PROCEDURE .............................. 85
Clutch Pressure Solenoid ....................................... 86
CONSULT-II REFERENCE VALUE IN DATA
MONITOR MODE ................................................ 86
TRANSFER CONTROL UNIT TERMINALS AND REFERENCE VALUE ..........................................86
DIAGNOSTIC PROCEDURE ...............................87
COMPONENT INSPECTION ...............................90
2-4WD Solenoid ......................................................91
CONSULT-II REFERENCE VALUE IN DATA
MONITOR MODE ................................................91
TRANSFER CONTROL UNIT TERMINALS AND
REFERENCE VALUE ..........................................91
DIAGNOSTIC PROCEDURE ...............................91
COMPONENT INSPECTION ...............................94
Transfer Motor .........................................................95
CONSULT-II REFERENCE VALUE IN DATA
MONITOR MODE ................................................95
TRANSFER CONTROL UNIT TERMINALS AND
REFERENCE VALUE ..........................................96
DIAGNOSTIC PROCEDURE ...............................97
COMPONENT INSPECTION ............................. 102
Transfer Fluid Temperature ................................... 102
CONSULT-II REFERENCE VALUE IN DATA
MONITOR MODE .............................................. 102
TRANSFER CONTROL UNIT TERMINALS AND
REFERENCE VALUE ........................................ 102
DIAGNOSTIC PROCEDURE ............................. 103
COMPONENT INSPECTION ............................. 104
Clutch Pressure Switch ......................................... 105
CONSULT-II REFERENCE VALUE IN DATA
MONITOR MODE .............................................. 105
TRANSFER CONTROL UNIT TERMINALS AND
REFERENCE VALUE ........................................ 105
DIAGNOSTIC PROCEDURE ............................. 106
COMPONENT INSPECTION ............................. 107
Line Pressure Switch ............................................ 108
CONSULT-II REFERENCE VALUE IN DATA
MONITOR MODE .............................................. 108
TRANSFER CONTROL UNIT TERMINALS AND
REFERENCE VALUE ........................................ 108
DIAGNOSTIC PROCEDURE ............................. 109
COMPONENT INSPECTION .............................110
Throttle Position Signal (ECM) .............................. 111
DIAGNOSTIC PROCEDURE ............................. 111
ABS Operation Signal (ABS) ................................ 111
DIAGNOSTIC PROCEDURE ............................. 111
VDC Operation Signal (ABS) ................................112
DIAGNOSTIC PROCEDURE .............................112
TCS Operation Signal (ABS) ................................112
DIAGNOSTIC PROCEDURE .............................112
CAN Communication Line .....................................113
DIAGNOSTIC PROCEDURE .............................113
ATP Switch ............................................................113
CONSULT-II REFERENCE VALUE IN DATA
MONITOR MODE ..............................................113
TRANSFER CONTROL UNIT TERMINALS AND
REFERENCE VALUE ........................................113
DIAGNOSTIC PROCEDURE .............................114
COMPONENT INSPECTION .............................115
TROUBLE DIAGNOSIS FOR SYMPTOMS ............117
4WD Shift Indicator Lamp and 4LO Indicator Lamp
Do Not Turn ON ....................................................117
SYMPTOM: ........................................................117

TF-4
PRECAUTIONS
Revision: October 20052005 QX56
PRECAUTIONSPFP:00001
Precautions for Supplemental Restraint System (SRS) “AIR BAG” and “SEAT
BELT PRE-TENSIONER”
EDS002H3
The Supplemental Restraint System such as “AIR BAG” and “SEAT BELT PRE-TENSIONER”, used along
with a front seat belt, helps to reduce the risk or severity of injury to the driver and front passenger for certain
types of collision. This system includes seat belt switch inputs and dual stage front air bag modules. The SRS
system uses the seat belt switches to determine the front air bag deployment, and may only deploy one front
air bag, depending on the severity of a collision and whether the front occupants are belted or unbelted.
Information necessary to service the system safely is included in the SRS and SB section of this Service Man-
ual.
WAR NIN G:

To avoid rendering the SRS inoperative, which could increase the risk of personal injury or death
in the event of a collision which would result in air bag inflation, all maintenance must be per-
formed by an authorized NISSAN/INFINITI dealer.

Improper maintenance, including incorrect removal and installation of the SRS, can lead to per-
sonal injury caused by unintentional activation of the system. For removal of Spiral Cable and Air
Bag Module, see the SRS section.

Do not use electrical test equipment on any circuit related to the SRS unless instructed to in this
Service Manual. SRS wiring harnesses can be identified by yellow and/or orange harnesses or
harness connectors.
Precautions for Transfer Assembly and Transfer Control Unit ReplacementEDS002H4
When replacing transfer assembly or transfer control unit, check the 4WD shift indicator lamp as follows.
1. Turn ignition switch “ON”.
2. Check 4WD shift indicator lamp is turned ON for approx. 1 second.

If OK, the position between transfer assembly and transfer control unit is correct.

If NG, the position is different between transfer assembly and transfer control unit.
Adjust the position between transfer assembly and transfer control unit. Refer to TF-4, "
METHOD FOR
POSITION ADJUSTMENT" .
METHOD FOR POSITION ADJUSTMENT
1. Start engine. Run the engine for at least 10 seconds.
2. Stop vehicle and move A/T selector lever to “N” position with brake pedal depressed. Stay in "N" for at
least 2 seconds.
3. Turn 4WD shift switch to “2WD” position. Stay in "2WD" for at least 2 seconds.
4. Turn ignition switch “OFF”.
5. Start engine.
6. Erase self-diagnosis. Refer to TF-47, "
How to Erase Self-diagnostic Results" (with CONSULT-II) or TF-
53, "ERASE SELF-DIAGNOSIS" (without CONSULT-II).
7. Check 4WD shift indicator lamp. Refer to TF-32, "
CHECK BEFORE ENGINE IS STARTED" .
If 4WD shift indicator lamp does not indicate "2WD", install new transfer control unit and retry the above
check.
PrecautionsEDS002H5

Before connecting or disconnecting the transfer control
unit harness connector, turn ignition switch “OFF” and dis-
connect battery ground cable. Failure to do so may damage
the transfer control unit. Battery voltage is applied to trans-
fer control unit even if ignition switch is turned “OFF”.
SEF 2 89 H

TRANSFER FLUID
TF-11
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Revision: October 20052005 QX56
TRANSFER FLUIDPFP:31001
ReplacementEDS002I2
DRAINING
1. Stop the engine.
2. Remove the drain plug and gasket to drain the transfer fluid as
shown.
3. Install the new gasket on the drain plug and install the drain plug
in the transfer. Tighten the drain plug to specification.
CAUTION:
Do not reuse the gasket.
FILLING
1. Remove the filler plug and gasket. Fill with new specified fluid
until the fluid level reaches the specified limit near the filler plug
mounting hole as shown.
CAUTION:
Carefully fill the transfer with fluid. Filling should take
approximately three minutes.
2. Leave the vehicle for three minutes and then check the fluid
level again as shown.
3. Install the new gasket on the filler plug and install the filler plug
in the transfer. Tighten the filler plug to specification.
CAUTION:
Do not reuse the gasket.
InspectionEDS002I3
FLUID LEAKAGE AND FLUID LEVEL
1. Check for any fluid leaks from the transfer assembly or around it and correct as necessary.
2. Remove the filler plug to check the fluid level at the filler plug
mounting hole as shown.
CAUTION:
Do not start the engine while checking the fluid level.
3. Install the new gasket on the filler plug and install the filler plug
in the transfer. Tighten the filler plug to specification.
CAUTION:
Do not reuse the gasket.Drain plug : Refer to TF-144, "
COMPONENTS" .
SM A44 4B
Fluid capacity and grade : Refer to MA-11, "Fluids
and Lubricants" .
Filler plug : Refer to TF-144, "
COMPONENTS" .
SM A43 9B
Filler plug : Refer to TF-144, "COMPONENTS" .
SM A43 9B

TF-18
ALL-MODE 4WD SYSTEM
Revision: October 20052005 QX56
LINE PRESSURE SWITCH

With the transfer system design, control of the oil pressure provides the transmission of drive torque to the
front wheels. The main pressure to control the oil pressure is referred to as the line pressure.

The line pressure switch determines whether or not adequate line pressure has built up under different
operating conditions.

The line pressure switch turns ON when line pressure is produced.

The line pressure switch senses line pressure abnormalities and turns the 4WD warning lamp ON.
CLUTCH PRESSURE SWITCH

The clutch pressure switch determines whether or not adequate clutch pressure has built up under differ-
ent operating conditions.

The clutch pressure switch turns ON when clutch pressure is produced.

The clutch pressure switch senses clutch pressure abnormalities and turns the 4WD warning lamp ON.
TRANSFER FLUID TEMPERATURE SENSOR
The transfer temperature sensor detects the transfer fluid temperature and sends a signal to the transfer con-
trol unit.
TRANSFER CONTROL UNIT

Transfer control unit controls transfer control device by input signals of each sensor and each switch.

Self-diagnosis can be done.
TRANSFER CONTROL DEVICE
The transfer control device changes the state of transfer assembly between 2WD, AUTO, 4H⇔4LO with the
2WD, AUTO, 4H and 4LO signals of 4WD shift switch.
NOTE:

To shift between 4H⇔4LO, stop the vehicle, depress the brake pedal and shift the transmission selector
to the "N" position. Depress and turn the 4WD shift switch. The shift switch will not shift to the desired
mode if the transmission is not in "N" or the vehicle is moving. The 4LO indicator lamp will be lit when the
4LO is engaged.

Actuator motor and actuator position switch are integrated.
4WD SHIFT SWITCH AND INDICATOR LAMP
4WD Shift Switch
The 4WD shift switch allows selection from 2WD, AUTO, 4H or 4LO.
4WD Shift Indicator Lamp

Displays driving conditions selected by 4WD shift switch with 2WD, AUTO and 4H indicators while engine
is running. (When 4WD warning lamp is turned on, all 4WD shift indicator lamps are turned off.)

Turns ON for approximately 1 second when ignition switch is turned ON, for purpose of lamp check.
4LO Indicator Lamp

Displays 4LO condition while engine is running. 4LO indicator lamp flashes if transfer gear does not shift
completely under 2WD, AUTO, 4H⇔4LO. (When 4WD warning lamp is turned on, 4LO indicator lamp is
turned off.)

Turns ON for approximately 1 second when ignition switch is turned ON, for purpose of lamp check.

ALL-MODE 4WD SYSTEM
TF-19
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4WD WARNING LAMP
Turns ON or FLASH when there is a malfunction in 4WD system.
Also turns ON when ignition switch is turned ON, for purpose of lamp check. Turns OFF for approximately 1
second after the engine starts if system is normal.
4WD Warning Lamp Indication
*: When 4WD warning lamp is ON, all the 4WD shift indicator lamps turn OFF.
AT P WA R N I N G L A M P
Even if A/T selector lever is in “P” position, vehicle may move because A/T parking mechanism does not oper-
ate when transfer is under neutral condition. ATP warning lamp is turned on so as to indicate this condition to
the driver.
System DiagramEDS002HB
Condition Content 4WD warning lamp
During self-diagnosis Indicates the malfunction position by number of flickers. Flickers at malfunction mode.
Lamp check*Checks the lamp by turning ON during engine starting. After
engine starts, it turns OFF if there are no malfunctions.ON
Malfunction in 4WD system*Turns ON to indicate malfunction. When ignition switch is
turned to “OFF” or the malfunction is corrected, it turns OFF.ON
When vehicle is driven with different
diameters of front and rear tiresFlickers once every 2 seconds.
Turns OFF when ignition switch is “OFF”.Flickers once every 2 sec-
onds.
High fluid temperature in transfer unitWhen fluid temperature is high or fluid temperature sensor cir-
cuit is shorted, it flickers twice every second.
It turns OFF when fluid temperature becomes normal.Flickers twice a second.
Other than above (System is nor-
mal.)Lamp is OFF. OFF
WDIA0164E

TF-20
ALL-MODE 4WD SYSTEM
Revision: October 20052005 QX56
COMPONENTS FUNCTION
CAN CommunicationEDS002HC
SYSTEM DESCRIPTION
Refer to LAN-5, "CAN COMMUNICATION" .
Component parts Function
Transfer control unit Controls transfer control device and control valves.
Transfer control device Actuator motor and actuator position switch are integrated so as to switch driving types.
2-4WD shift solenoid valve Controls oil pressure and allows selection between 2WD and 4WD.
Clutch pressure solenoid valve Controls oil pressure and distributes torque (front and rear).
Line pressure switch Detects line pressure.
Clutch pressure switch Detects clutch pressure.
Transfer fluid temperature sen-
sorDetects transfer fluid temperature.
Wait detection switch Detects whether or not 4WD lock gear is locked.
Neutral-4LO switch Detects that transfer is under neutral-4LO condition (or shifting through neutral).
ATP switch Detects that transfer is under neutral condition.
4WD shift switch Allows selection from 2WD, AUTO, 4H or 4LO.
4WD warning lamp

Illuminates if malfunction is detected in electrical system of 4WD system.

There is 1 blink every 2 seconds if rotation difference of front wheels and rear wheels is large.

There is 2 blinks every 1 second if high transfer fluid temperature is detected.
ATP warning lampIndicates that A/T parking mechanism does not operate when A/T selector lever is in “P” position
and transfer is under neutral condition.
4WD shift indicator lamp Displays driving condition selected by 4WD shift switch.
4LO indicator lamp Displays 4LO condition.
ABS actuator and electric unit
(control unit)Transmits vehicle speed signal via CAN communication to transfer control unit.
TCMTransmits the following signals via CAN communication to transfer control unit.

Output shaft revolution signal

A/T position indicator signal (PNP switch signal)
ECMTransmits the following signals via CAN communication to transfer control unit.

Engine speed signal

Accelerator pedal position signal

TF-32
TROUBLE DIAGNOSIS
Revision: October 20052005 QX56
Inspections Before Trouble DiagnosisEDS002HH
TRANSFER FLUID CHECK
Check fluid for leaks and fluid level. Refer to TF-11, "Inspection" .
PREPARATION FOR ROAD TEST

The purpose of the test is to determine overall performance of
transfer and analyze causes of problems.

When a malfunction is found in any part of transfer, perform the
road test to locate the malfunction area and repair the malfunc-
tion parts.

The road test consists of the following three parts.
–Check before engine is started. Refer to TF-32, "CHECK
BEFORE ENGINE IS STARTED" .
–Check at idle. Refer to TF-32, "CHECK AT IDLE" .
–Cruise test. Refer to TF-34, "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 TF-117, "
4WD Shift Indicator Lamp and 4LO Indicator Lamp Do Not Turn ON" .
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.)
Does 4WD warning lamp turn ON?
YES >> GO TO TF-32, "CHECK AT IDLE" .
NO >> GO TO TF-121, "
4WD Warning Lamp Does Not Turn ON" .
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.
SMT089D