warning INFINITI QX4 2005 Factory Service Manual

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Revision: October 20052005 QX56 DIAGNOSTIC PROCEDURE ............................. 117
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 ...............................................140
Removal and Installation ......................................140
REMOVAL .........................................................140
INSTALLATION .................................................140
TRANSFER OIL FILTER .........................................141
Removal and Installation ......................................141
REMOVAL .........................................................141
INSTALLATION .................................................141
TRANSFER ASSEMBLY ........................................143
Removal and Installation ......................................143
REMOVAL .........................................................143
INSTALLATION .................................................143
Disassembly and Assembly ..................................144
COMPONENTS .................................................144
DISASSEMBLY .................................................146
INSPECTION AFTER DISASSEMBLY ..............161
ASSEMBLY .......................................................165
SERVICE DATA AND SPECIFICATIONS (SDS) ....181
General Specifications ..........................................181
Inspection and Adjustment ...................................181
CLEARANCE BETWEEN INNER GEAR AND
OUTER GEAR ...................................................181
CLUTCH ............................................................181
PINION GEAR END PLAY ................................181
CLEARANCE BETWEEN SHIFT FORK AND
SLEEVE ............................................................181
SELECTIVE PARTS ..........................................181

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
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Revision: October 20052005 QX56
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

TROUBLE DIAGNOSIS
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2. CHECK 4WD WARNING LAMP
Check 4WD warning lamp state?
Is 4WD warning lamp turned ON?
YES >> Perform the self-diagnosis. Refer to TF-50, "SELF-DIAGNOSTIC PROCEDURE (WITH CON-
SULT-II)" (with CONSULT-II) or TF-50, "SELF-DIAGNOSTIC PROCEDURE (WITHOUT CON-
SULT-II)" (without CONSULT-II).
NO >> Go to TF-123, "
4WD Shift Indicator Lamp or 4LO Indicator Lamp Does Not Change" .
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 second.)
Do 4WD shift indicator and 4LO indicator lamps change properly?
Does buzzer sound?
YES >> GO TO 4.
NO >> GO TO TF-123, "
4WD Shift Indicator Lamp or 4LO Indi-
cator Lamp Does Not Change" .
4. CHECK ATP WARNING LAMP
1. Move the A/T selector lever to “P” position.
2. Set 4WD shift switch from “4HI” to "4LO".
While switching from "4HI" to "4LO", does 4WD shift indicator lamp turn OFF and ATP warning lamp turn ON?
YES >> GO TO TF-125, "ATP Warning Lamp Turns ON" .
NO >> GO TO 5.
5. CHECK "WAIT" FUNCTION
1. Set 4WD shift switch from “4LO” to "4H".
2. Check 4LO indicator lamp state.
NOTE:
While “wait” function is operating, 4LO indicator lamp flashes.
Does 4LO indicator lamp flicker?
YES >> GO TO TF-127, "4LO Indicator Lamp Repeats Flashing" .
NO >>TF-34, "
CRUISE TEST".
WDIA0136E

TF-34
TROUBLE DIAGNOSIS
Revision: October 20052005 QX56
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).
Check 4WD warning lamp turned ON?
On steady>>Perform the self-diagnosis. Refer to TF-50, "SELF-DIAGNOSTIC PROCEDURE (WITH CON-
SULT-II)" (with CONSULT-II) or TF-50, "SELF-DIAGNOSTIC PROCEDURE (WITHOUT CON-
SULT-II)" (without CONSULT-II).
Flash rapidly>>GO TO TF-128, "
4WD Warning Lamp Flashes Rapidly" .
Flash slowly>>GO TO TF-129, "
4WD Warning Lamp Flashes Slowly" .
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 TF-130, "Heavy Tight-corner Braking Symptom Occurs" .
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 TF-131, "
4WD System Does Not Operate" .
Trouble Diagnosis Chart for SymptomsEDS002HI
If 4WD warning lamp turns ON, perform self-diagnosis. Refer to TF-50, "Self-diagnostic Procedure" .
Symptom Condition Check item Reference page
4WD shift indicator lamp and 4LO indicator
lamp do not turn ON
(4WD shift indicator lamp and 4LO indicator
lamp check)Ignition switch: ONPower supply and ground for transfer
control unit
TF-117
Transfer shut off relay
Combination meter
4WD warning lamp does not turn ON
(4WD warning lamp check)Ignition switch: ONPower supply and ground for transfer
control unit
TF-121
Transfer shut off relay
Combination meter

TROUBLE DIAGNOSIS
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NOTE:

Light tight-corner braking symptom may occur depending on driving conditions in AUTO mode. This is not
a malfunction.

Heavy tight-corner braking symptom occurs when vehicle is driven in the following conditions: 4WD shift
switch is "4H" or "4LO", steering wheel is turned fully to either side.
4WD shift indicator lamp or 4LO indicator
lamp does not changeEngine running4WD shift switch
TF-123
Wait detection switch
Neutral-4LO switch
ATP switch
2-4WD solenoid
Transfer control device
Actuator motor
Actuator position switch
Transfer inner parts
ATP warning lamp turns ON Engine runningCAN communication line
TF-125
4WD shift switch
PNP switch signal
ATP switch
Combination meter
Transfer inner parts
4LO indicator lamp repeats flashing Engine runningWait detection switch
TF-127
Neutral-4LO switch
Transfer inner parts
4WD warning lamp flashes rapidly (2 times/
second)While drivingTransfer fluid temperature
TF-128
Tire size is different between front and
rear of vehicle
4WD warning lamp flashes slowly
(1 time/2 seconds)While drivingTire size is different between front and
rear of vehicle.
TF-129
Transfer fluid temperature
Clutch pressure switch
Heavy tight-corner braking symptom occurs
(See NOTE.)

While driving

AUTO mode

Steering wheel is
turned fully to either
sideCAN communication line
TF-130
4WD shift switch
Accelerator pedal position signal
Clutch pressure solenoid
Transfer inner parts
4WD system does not operate While driving4WD shift switch
TF-131
Clutch pressure switch
Transfer inner parts Symptom Condition Check item Reference page

TROUBLE DIAGNOSIS
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MOTOR RELAY MON
[ON/OFF]Check signal for transfer
control unit signal output

Accelerator pedal
depressed

Vehicle stopped

Engine running

Brake pedal depressed4WD shift switch: 2WD OFF
4WD shift switch: AUTO
or 4LO (A/T selector lever
“P” or “N” position)OFF
("ON" for approx. 2
sec. after shifting
to “P” and “N”.)
4WD shift switch: AUTO
or 4LO (Except for A/T
selector lever “P” or “N”
position)ON
4WD shift switch: 4H (A/T
selector lever “P” posi-
tion)OFF
("ON" for approx. 2
sec. after shifting
to “P”.)
4WD shift switch: 4H
(Except for A/T selector
lever “P” position)ON
4WD FAIL LAMP [ON/
OFF]Condition of 4WD warn-
ing lamp4WD warning lamp: ON ON
4WD warning lamp: OFF OFF
2WD IND [ON/OFF]Condition of 4WD shift
indicator lamp (2WD
indicator lamp)2WD indicator lamp of 4WD shift indicator lamp: OFF OFF
2WD indicator lamp of 4WD shift indicator lamp: ON ON
AUTO IND [ON/OFF]Condition of 4WD shift
indicator lamp (AUTO
indicator lamp)AUTO indicator lamp of 4WD shift indicator lamp: OFF OFF
AUTO indicator lamp of 4WD shift indicator lamp: ON ON
LOCK IND [ON/OFF]Condition of 4WD shift
indicator lamp (Lock indi-
cator lamp)Lock indicator lamp of 4WD shift indicator lamp: OFF OFF
Lock indicator lamp of 4WD shift indicator lamp: ON ON
4L IND [ON/OFF]Condition of 4LO indica-
tor lamp condition4LO indicator lamp: OFF OFF
4LO indicator lamp: ON ON
AT P I N D [O N / O F F ]Condition of ATP indica-
tor lamp ATP indicator lamp: ON ON
ATP indicator lamp: OFF OFF
SHIFT POS SW1 [ON/
OFF]Condition of actuator
position switch 1
(Low)

Vehicle stopped

Engine running

A/T selector lever “N” posi-
tion

Brake pedal depressed4WD shift switch: 4LO ON
4WD shift switch: 2WD,
AUTO or 4HOFF
SHIFT POS SW2 [ON/
OFF]Condition of actuator
position switch 2
(High)

Vehicle stopped

Engine running

A/T selector lever “N” posi-
tion

Brake pedal depressed4WD shift switch: 4H,
AUTO or 2WDON
4WD shift switch: 4LO OFF
SHIFT ACT1 [ON/OFF]Output condition to actu-
ator motor (High)

Vehicle stopped

Engine running

A/T selector lever “N” posi-
tion

Brake pedal depressed4WD shift switch: 4H to
4LO (“Wait” function is
operating.)ON
Except the above OFF
SHIFT AC MON1 [ON/
OFF]Check signal for transfer
control unit signal output

Vehicle stopped

Engine running

A/T selector lever “N” posi-
tion

Brake pedal depressed4WD shift switch: 4H to
4LO (“Wait” function is
operating.)ON
Except the above OFF Monitored item [Unit] Content Condition Display value

TF-40
TROUBLE DIAGNOSIS
Revision: October 20052005 QX56
Specifications Between Transfer Control Unit Terminals
TRANSFER CONTROL UNIT TERMINAL CONNECTOR LAYOUT
NOTE:
Data are reference value and are measured between each terminal and ground.
SHIFT ACT2 [ON/OFF]Output condition to actu-
ator motor (Low)

Vehicle stopped

Engine running

A/T selector lever “N” posi-
tion

Brake pedal depressed4WD shift switch: 4LO to
4H (“Wait” function is
operating.)ON
Except the above OFF
SHIFT AC MON2 [ON/
OFF]Check signal for transfer
control unit signal output

Vehicle stopped

Engine running

A/T selector lever “N” posi-
tion

Brake pedal depressed4WD shift switch: 4LO to
4H (“Wait” function is
operating.)ON
Except the above OFF
T/F F SPEED [km/h] or
[mph]Displayed, but do not use.
A/T R SPEED [km/h] or
[mph]Condition of vehicle
speed sensor A/T (Revo-
lution sensor)During drivingApproximately
matches the out-
put shaft speed.
AT GEAR POSI [1/2/3/4/
5]Condition of A/T selec-
tor lever positionDisplays actual A/T gear position. 1/2/3/4/5 Monitored item [Unit] Content Condition Display value
WDIA0204E
Te r m i n a lWire
colorItem Condition Data (Approx.)
1 GR 2-4WD shift solenoid valve

Vehicle stopped

Engine running

A/T selector lever
“N” position

Brake pedal
depressed4WD shift switch: 2WD 0V
4WD shift switch: AUTO, 4H or 4LO Battery voltage
2 B/W4WD shift indicator lamp
(2WD indicator lamp)2WD indicator lamp: OFF Battery voltage
2WD indicator lamp: ON 0V
3 B Ground Always 0V
4 Y/L Transfer shift high relay

Vehicle stopped

Engine running

A/T selector lever
“N” position

Brake pedal
depressed4WD shift switch: 4H to 4LO (“Wait” func-
tion is operating.)Battery voltage
Except the above 0V
5 W/B 4WD warning lamp4WD warning lamp: ON 0V
4WD warning lamp: OFF Battery voltage