4WD INFINITI QX56 2006 Factory Repair Manual

TF-2Revision: November 20092006 QX56
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 ....................................... ... 86DIAGNOSTIC 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
DIAGNOSTIC PROCEDURE ............................ .117

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4WD Warning Lamp Does Not Turn ON .............
. 121
SYMPTOM: ...................................................... . 121
DIAGNOSTIC PROCEDURE ........................... . 121
4WD Shift Indicator Lamp or 4LO Indicator Lamp
Does Not Change ................................................ . 123
SYMPTOM: ...................................................... . 123
DIAGNOSTIC PROCEDURE ........................... . 124
ATP Warning Lamp Turns ON ............................. . 125
SYMPTOM: ...................................................... . 125
DIAGNOSTIC PROCEDURE ........................... . 125
4LO Indicator Lamp Repeats Flashing ................ . 127
SYMPTOM: ...................................................... . 127
DIAGNOSTIC PROCEDURE ........................... . 127
4WD Warning Lamp Flashes Rapidly ................. . 128
SYMPTOM: ...................................................... . 128
DIAGNOSTIC PROCEDURE ........................... . 128
4WD Warning Lamp Flashes Slowly ................... . 129
SYMPTOM: ...................................................... . 129
DIAGNOSTIC PROCEDURE ........................... . 129
Heavy Tight-corner Braking Symptom Occurs .... . 130
SYMPTOM: ...................................................... . 130
DIAGNOSTIC PROCEDURE ........................... . 130
4WD System Does Not Operate ......................... . 131
SYMPTOM: ...................................................... . 131
DIAGNOSTIC PROCEDURE ........................... . 131
TRANSFER CONTROL UNIT ................................ . 132
Removal and Installation ..................................... . 132
REMOVAL ........................................................ . 132
INSTALLATION ................................................ . 132
FRONT OIL SEAL ................................................. . 133
Removal and Installation ..................................... . 133
REMOVAL ........................................................ . 133
INSTALLATION ................................................ . 134
REAR OIL SEAL ................................................... . 135
Removal and Installation ..................................... . 135
REMOVAL ........................................................ . 135
INSTALLATION ................................................ . 135SIDE OIL SEAL ......................................................
.137
Removal and Installation ..................................... .137
REMOVAL ........................................................ .137
INSTALLATION ................................................ .137
TRANSFER CONTROL DEVICE ........................... .138
Removal and Installation ..................................... .138
AIR BREATHER HOSE ......................................... .139
Removal and Installation ..................................... .139
TRANSFER MOTOR .............................................. .142
Removal and Installation ..................................... .142
REMOVAL ........................................................ .142
INSTALLATION ................................................ .142
TRANSFER OIL FILTER ........................................ .143
Removal and Installation ..................................... .143
REMOVAL ........................................................ .143
INSTALLATION ................................................ .143
TRANSFER ASSEMBLY ....................................... .145
Removal and Installation ..................................... .145
REMOVAL ........................................................ .145
INSTALLATION ................................................ .145
Disassembly and Assembly ................................. .146
COMPONENTS ................................................ .146
DISASSEMBLY ................................................ .148
INSPECTION AFTER DISASSEMBLY ............. .163
ASSEMBLY ...................................................... .167
SERVICE DATA AND SPECIFICATIONS (SDS) ... .183
General Specifications ......................................... .183
Inspection and Adjustment .................................. .183
CLEARANCE BETWEEN INNER GEAR AND
OUTER GEAR .................................................. .183
CLUTCH ........................................................... .183
PINION GEAR END PLAY ............................... .183
CLEARANCE BETWEEN SHIFT FORK AND
SLEEVE ........................................................... .183
SELECTIVE PARTS ......................................... .183

TF-4
PRECAUTIONS
Revision: November 20092006 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.
WARNING:

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”.
SEF289H

TF-12
ALL-MODE 4WD SYSTEM
Revision: November 20092006 QX56
ALL-MODE 4WD SYSTEMPFP:00000
Cross-section ViewEDS002H8
1. Center case2. Front case 3. Internal gear
4. Planetary carrier assembly 5. Sun gear assembly 6. Main shaft
7. L-H sleeve 8. L-H fork 9. Shift rod
10. 2-4 sleeve 11. 2-4 fork 12. Drive chain
13. Front drive shaft 14. Control valve assembly 15. Transfer motor
16. Rear case 17. Clutch piston 18. Press flange
19. Multiple disc clutch 20. Clutch hub assembly 21. Clutch drum assembly
WDIA0202E

ALL-MODE 4WD SYSTEMTF-13
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Power TransferEDS002H9
POWER TRANSFER DIAGRAM
1. Center case2. Chain3. Multiple disc clutch
4. Rear case 5. Mainshaft6. Clutch hub assembly
7. Sub oil pump 8. Transfer motor9. Control valve
10. Front drive shaft 11. Drain plug12. 2-4 sleeve
13. Sun gear assembly 14. L-H sleeve15. Planetary carrier assembly
16. Internal gear 17. Front case
LDIA0053E

TF-14
ALL-MODE 4WD SYSTEM
Revision: November 20092006 QX56
POWER TRANSFER FLOW
SDIA3327E

ALL-MODE 4WD SYSTEMTF-15
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System DescriptionEDS002HA
CONTROL SYSTEM
WDIA0162E

TF-16
ALL-MODE 4WD SYSTEM
Revision: November 20092006 QX56
ALL-MODE 4WD Transfer Basic Control
Hydraulic Control Circuits
TRANSFER MOTOR

The transfer motor drives the sub-oil pump to provide proper lubrication and oil pressure control when the
vehicle is at standstill, during low-speed operations or is being driven in reverse.

The main oil pump is operated by the driving force of the mainshaft. In other words, sufficient oil pressure
buildup does not occur when the vehicle is at standstill or during low-speed operations. While the vehicle
is being driven in reverse, the main oil pump rotates in the reverse direction. Therefore the main oil pump
does not discharge oil pressure. During any of the above vehicle operations, the transfer motor drives the
sub-oil pump to compensate for insufficient oil pressure.

The transfer motor operates as follows.
–The motor relay turns OFF in the 2WD mode.
–The motor relay operates as described in the table below in modes other than the 2WD mode.
LDIA0055E
WDIA0163E

ALL-MODE 4WD SYSTEMTF-17
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Transfer Motor Relay Operation
*: After 2.5 seconds have elapsed.

4WD shift switch, PNP switch, Neutral-4LO switch, vehicle speed sensor and throttle position sensor are
used in conjunction with the transfer motor.
WAIT DETECTION SWITCH

The wait detection switch operates when there is “circulating” torque produced in the propeller shaft
(L → H) or when there is a phase difference between 2-4 sleeve and clutch drum (H →L). After the release
of the “circulating ” torque, the wait detection switch helps provide the 4WD lock gear (clutch drum) shifts.
A difference may occur between the operation of the 4WD shift switch and actual drive mode. At this
point, the wait detection switch senses an actual drive mode.

The wait detection switch operates as follows.
–4WD lock gear (clutch drum) locked: ON
–4WD lock gear (clutch drum) released: OFF

The wait detection switch senses an actual drive mode and the 4WD shift indicator lamp indicates the
vehicle drive mode.
NEUTRAL-4LO SWITCH
The neutral-4LO switch detects that transfer gear is in neutral or 4LO (or shifting from neutral to 4LO) condi-
tion by L-H shift fork position.
AT P S W I T C H
ATP switch detects if transfer gear is in a neutral condition by L-H shift fork position.
NOTE:
Transfer gear may be in a neutral condition in 4H-4LO.
2-4WD SHIFT SOLENOID VALVE
The 2-4WD shift solenoid valve operates to apply oil pressure to the wet-multiplate clutch, depending on the
drive mode. The driving force is transmitted to the front wheels through the clutch so the vehicle is set in the
4WD shift switch A/T selector lever position Vehicle speed
(VSS) Accelerator pedal position Motor relay drive
command
2WD ——— OFF
4H (LOCK) and 4LO “
N ” position 0— ON
“ P ” position 00 - 0.07/8
OFF*
0.07/8 - 1/8 HOLD
1/8 - MAX ON
Other than “ R” position 0 < VSS
≤ 50 km/h (31 MPH)
— ON
50 km/h (31 MPH) < VSS < 55 km/h (34 MPH) HOLD
55 km/h (34 MPH) ≤ VSS OFF
“ R ” position —— ON
“ R ” position —— ON
AUTO “
P ” or “ N” position 0
0 - 0.07/8
OFF*
0.07/8 - 1/8 HOLD
1/8 - MAX ON
0 < VSS ≤ 50 km/h (31 MPH)
— ON
50 km/h (31 MPH) < VSS < 55 km/h (34 MPH) HOLD
55 km/h (34 MPH) ≤ VSS OFF
Other than “ R”, "P" and "N"
position 0 < VSS
≤ 50 km/h (31 MPH)
— ON
50 km/h (31 MPH) < VSS < 55 km/h (34 MPH) HOLD
55 km/h (34 MPH) ≤ VSS OFF

TF-18
ALL-MODE 4WD SYSTEM
Revision: November 20092006 QX56
4WD mode. Setting the vehicle in the 2WD mode requires no pressure buildup. In other words, pressure force
applied to the wet-multiplate clutch becomes zero.
CLUTCH PRESSURE SOLENOID VALVE
The clutch pressure solenoid valve distributes torque (front and rear) in AUTO mode.
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.