2011 INFINITI QX56 4WD

DLN-2
Work Procedure ......................................................47
CONFIGURATION (TRANSFER CONTROL
UNIT) ..................................................................
48
Description ........................................................... ...48
Work Procedure ......................................................48
DTC/CIRCUIT DIAGNOSIS ...................... ...51
P1802, P1803, P1804, P1809 TRANSFER
CONTROL UNIT ............................................. ...
51
DTC Logic ............................................................ ...51
Diagnosis Procedure ..............................................51
P1807 OUT PUT SHAFT SPEED SENSOR ......52
DTC Logic ............................................................ ...52
Diagnosis Procedure ..............................................52
P1808 WHEEL SPEED SENSOR ......................53
DTC Logic ............................................................ ...53
Diagnosis Procedure ..............................................53
P180C SENSOR POWER SUPPLY (5V) ..........54
Description ........................................................... ...54
DTC Logic ...............................................................54
Diagnosis Procedure ..............................................54
P180D TRANSFER ROTARY POSITION
SENSOR ............................................................
57
DTC Logic ............................................................ ...57
Diagnosis Procedure ..............................................57
P180E SENSOR POWER SUPPLY (8V) ...........59
Description ........................................................... ...59
DTC Logic ...............................................................59
Diagnosis Procedure ..............................................59
P180F TRANSFER INTERNAL SPEED SEN-
SOR ....................................................................
61
DTC Logic ............................................................ ...61
Diagnosis Procedure ..............................................61
P1811 POWER SUPPLY CIRCUIT FOR
TRANSFER CONTROL UNIT ............................
64
Description ........................................................... ...64
DTC Logic ...............................................................64
Diagnosis Procedure ..............................................64
P1813 4WD MODE SWITCH .............................67
DTC Logic ............................................................ ...67
Diagnosis Procedure ..............................................67
Component Inspection ............................................68
P1816 PARKING/NEUTRAL POSITION
SWITCH .............................................................
69
DTC Logic ............................................................ ...69
Diagnosis Procedure ..............................................69
P1817 TRANSFER MOTOR ..............................70
DTC Logic ............................................................ ...70
Diagnosis Procedure ..............................................70
Component Inspection ......................................... ...71
P181A TRANSFER MOTOR TEMPERATURE
SENSOR ............................................................
72
DTC Logic ............................................................ ...72
Diagnosis Procedure ...............................................72
Component Inspection ............................................73
P181B INCOMPLETE SELFSHUT ....................74
DTC Logic ............................................................ ...74
Diagnosis Procedure ...............................................74
P181C TRANSFER MOTOR POWER SUP-
PLY ....................................................................
76
Description ........................................................... ...76
DTC Logic ...............................................................76
Diagnosis Procedure ...............................................76
P181E STEERING ANGLE SENSOR ...............77
DTC Logic ............................................................ ...77
Diagnosis Procedure ...............................................77
P181F INCOMPLETE CALIBRATION ..............78
DTC Logic ............................................................ ...78
Diagnosis Procedure ...............................................78
P1820 ENGINE SPEED SIGNAL ......................79
DTC Logic ............................................................ ...79
Diagnosis Procedure ...............................................79
P1826 TRANSFER FLUID TEMPERATURE ....80
DTC Logic ............................................................ ...80
Diagnosis Procedure ...............................................80
Component Inspection ............................................81
P1829 ACCELERATOR PEDAL POSITION
SENSOR ............................................................
82
DTC Logic ............................................................ ...82
Diagnosis Procedure ...............................................82
P182A TRANSFER HI-LO POSITION SEN-
SOR ...................................................................
83
DTC Logic ............................................................ ...83
Diagnosis Procedure ...............................................83
P182B TRANSFER LOCK POSITION SEN-
SOR ...................................................................
85
DTC Logic ............................................................ ...85
Diagnosis Procedure ...............................................85
P1830 ABS OPERATION SIGNAL ...................88
DTC Logic ............................................................ ...88
Diagnosis Procedure ...............................................88
P1831 VDC OPERATION SIGNAL ...................89
DTC Logic ............................................................ ...89
Diagnosis Procedure ...............................................89
P1832 TCS OPERATION SIGNAL ....................90
DTC Logic ............................................................ ...90
Diagnosis Procedure ...............................................90
Revision: 2010 May2011 QX56

DLN-3
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U1000 CAN COMM CIRCUIT ......................... ....91
Description .......................................................... ....91
DTC Logic ...............................................................91
Diagnosis Procedure ...............................................91
U1010 CONTROL UNIT (CAN) ..........................92
Description .......................................................... ....92
DTC Logic ...............................................................92
Diagnosis Procedure ...............................................92
POWER SUPPLY AND GROUND CIRCUIT ......93
Description .......................................................... ....93
Diagnosis Procedure ...............................................93
4WD WARNING LAMP ......................................97
Component Function Check ................................ ....97
Diagnosis Procedure ...............................................97
4WD INDICATOR LAMP ....................................98
Component Function Check ................................ ....98
Diagnosis Procedure ...............................................98
SYMPTOM DIAGNOSIS ..............................99
HEAVY TIGHT-CORNER BRAKING SYMP-
TOM OCCURS . .............................................. ....
99
Description .......................................................... ....99
Diagnosis Procedure ...............................................99
4WD MODE DOES NOT CHANGE ..................100
Description .......................................................... ..100
Diagnosis Procedure .............................................100
4WD MODE INDICATOR LAMP CONTINUES
BLINKING .........................................................
101
Description .......................................................... ..101
Diagnosis Procedure .............................................101
4WD WARNING LAMP BLINKS QUICKLY .....102
Description .......................................................... ..102
4WD WARNING LAMP BLINKS SLOWLY .....103
Description .......................................................... ..103
Diagnosis Procedure .............................................103
INFORMATION DISPLAY IS NOT DIS-
PLAYED ...........................................................
104
Description .......................................................... ..104
Diagnosis Procedure .............................................104
NOISE, VIBRATION AND HARSHNESS
(NVH) TROUBLESHOOTING ..........................
105
NVH Troubleshooting Chart ................................ ..105
PERIODIC MAINTENANCE .......................106
TRANSFER FLUID ......................................... ..106
Inspection ............................................................ ..106
Draining .................................................................106
Refilling .................................................................106
REMOVAL AND INSTALLATION .............107
TRANSFER CONTROL UNIT .........................107
Removal and Installation ..................................... ..107
4WD MODE SWITCH ......................................108
Removal and Installation .......................................108
FRONT OIL SEAL ...........................................109
Exploded View .......................................................109
Removal and Installation .......................................109
REAR OIL SEAL .............................................111
Exploded View .......................................................111
Removal and Installation .......................................111
Adjustment .............................................................112
TRANSFER CONTROL ACTUATOR .............114
Exploded View .......................................................114
Removal and Installation .......................................114
Inspection ..............................................................114
TRANSFER HI-LO POSITION SENSOR ........116
Exploded View .......................................................116
Removal and Installation .......................................116
Inspection ..............................................................116
TRANSFER ROTARY POSITION SENSOR ...117
Exploded View .......................................................117
Removal and Installation .......................................117
Inspection ..............................................................118
TRANSFER LOCK POSITION SENSOR ........119
Exploded View .......................................................119
Removal and Installation .......................................119
Inspection ..............................................................119
TRANSFER FLUID TEMPERATURE SEN-
SOR .................................................................
120
Exploded View .......................................................120
Removal and Installation .......................................120
Inspection ..............................................................120
UNIT REMOVAL AND INSTALLATION ....121
TRANSFER ASSEMBLY ................................121
Exploded View ..................................................... ..121
Removal and Installation .......................................121
INPUT OIL SEAL ............................................123
Exploded View .......................................................123
Removal and Installation .......................................123
SERVICE DATA AND SPECIFICATIONS
(SDS) ............... ...........................................
124
SERVICE DATA AND SPECIFICATIONS
(SDS) ...............................................................
124
General Specifications ......................................... ..124
FRONT PROPELLER SHAFT: 2F P15
PREPARATION ........ .................................
125
PREPARATION ...............................................125
Revision: 2010 May2011 QX56

DLN-10
< SYSTEM DESCRIPTION >[TRANSFER: ATX90A]
COMPONENT PARTS
SYSTEM DESCRIPTION
COMPONENT PARTS
Component Parts LocationINFOID:0000000006222214
1. ECM
Refer to EC-16, "
Component Parts
Location". 2. ABS actuator and electric unit (con-
trol unit)
Refer to BRC-10, "Component Parts
Location". 3. Steering angle sensor
Refer to BRC-10, "
Component Parts
Location".
4. Control valve & TCM Refer to TM-10, "
A/T CONTROL
SYSTEM : Compon ent Parts Loca-
tion". 5. Transfer control unit 6. 4WD switch assembly
7. Transfer lock position sensor 8. Transfer Hi-Lo position sensor 9. Transfer rotary position sensor
10. Transfer control actuator 11. Transfer fluid temperature sensor
A. Back of glove box assembly B. 4WD indicator lamp, 4WD warning lamp, ATP warning lamp (in combina-
tion meter)C. Console assembly
D. Transfer assembly upper side E. Transfer assembly under side
JPDIE0270GB
Revision: 2010 May2011 QX56

COMPONENT PARTSDLN-11
< SYSTEM DESCRIPTION > [TRANSFER: ATX90A]
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Component DescriptionINFOID:0000000006222215
Transfer Control UnitINFOID:0000000006222216
 Transfer control unit operates transfer control act uator, 4WD warning lamp and 4WD mode indicator lamp
according to input signal from 4WD shift switch and each sensor and control unit.
 When 4WD system is malfunctioning, 4WD warning la mp turns ON and fail-safe status activates.
 When protection is necessary, 4WD warning la mp blinks and protection status activates.
Transfer Control ActuatorINFOID:0000000006222217
Transfer control actuator integrates transfer motor, transfer internal position sensor, and transfer motor tem-
perature sensor, and switches 4WD mode (AUTO ⇔4H ⇔4L).
TRANSFER MOTOR
Transfer motor operates according to signal from transfer control unit and switches 4WD mode
(AUTO ⇔4H ⇔4L). It also performs front and rear distri bution of traction force during AUTO mode.
TRANSFER INTERNAL SPEED SENSOR
Transfer internal speed sensor detects rotation status of transfer motor and transmits signal to transfer control
unit.
TRANSFER MOTOR TEMPERATURE SENSOR
 Transfer motor temperature sensor m easures temperature of transfer motor.
Component parts Reference/Function
Transfer control unit DLN-11, "
Transfer Control Unit"
Transfer control actua-
torTransfer motor
DLN-11, "
Transfer Control Actuator"
Transfer internal speed
sensorDLN-11, "Transfer Control Actuator"
Transfer motor temper-
ature sensor
DLN-11, "Transfer Control Actuator"
Transfer Hi-Lo position sensor
DLN-12, "Transfer Hi-Lo Position Sensor"
Transfer rotary position sensorDLN-12, "Transfer Rotary Position Sensor"
Transfer lock position sensorDLN-12, "Transfer Lock Position Sensor"
Transfer fluid temperature sensorDLN-12, "Transfer Fluid Temperature Sensor"
4WD mode switchDLN-18, "4WD SYSTEM : System Description"
4WD indicator lampDLN-18, "4WD SYSTEM : System Description"
4WD warning lampDLN-18, "4WD SYSTEM : System Description"
AT P w a r n i n g l a m pDLN-18, "4WD SYSTEM : System Description"
ABS actuator and electric unit (control unit)Transmits the following signals via CAN communication line to transfer control unit.
 Vehicle speed signal (ABS)
 Stop lamp switch signal (brake signal)
 ABS operation signal
 VDC operation signal
 TCS operation signal
Steering angle sensor Transmits the following signals via CAN communication line to transfer control unit.
 Steering angle sensor signal
ECM Transmits the following signals via CAN communication line to transfer control unit.
 Accelerator pedal position signal
 Engine speed signal
 Engine torque signal
TCM Transmits the following signals via CAN communication line to transfer control unit.
 Shift position signal
 Gear position signal
 Output shaft revolution signal
Revision: 2010 May2011 QX56

DLN-14
< SYSTEM DESCRIPTION >[TRANSFER: ATX90A]
STRUCTURE AND OPERATION
DESCRIPTION
 Ball ramp lever operates in the direction of main shaft axis according to rotation of actuator shaft and
presses piston. Pressure is applied to each clutch and torque is transmitted.
 Shift fork operates in the direction of main shaft axis according to rotation of actuator shaft and performs
engagement and disengagement to Hi-Lo sleeve and lock sleev e of main shaft. Mode is switched between
4H ⇔4L.
AUTO MODE
 The optimum torque distribution is electronically performed for front and rear wheels according to road con-
ditions.
 Stable start without wheel spin is possible on slippery road conditions, such as on a snowy road.
 When road condition does not require 4WD driving, the st atus becomes close to rear wheel drive, which
results in better fuel efficiency and prov ides FR-like steering characteristics.
 The vehicle cornering status is judged according to information from each sensor, and the optimum torque is
distributed to front wheels for prev enting tight-corner braking symptom.
NOTE:
When there is a difference of revolution speed between the front and rear wheel the shift occasionally changes
to direct 4-wheel driving conditions aut omatically. This is not a malfunction.
4H MODE
 Torque distribution for front and rear wheels is fixed and stable start is achieved while driving on an rough,
sandy or snowy road.
4L MODE
 Large traction force is obtained due to low gear. High running ability and escaping ability are achieved.
 Switching from 4H mode to 4L mode is not possible w hen the vehicle is not stopped and A/T shift selector is
not in the neutral position.
TORQUE DISTRIBUTION DIAGRAM
JPDIE0256GB
Revision: 2010 May2011 QX56

DLN-18
< SYSTEM DESCRIPTION >[TRANSFER: ATX90A]
SYSTEM
SYSTEM
4WD SYSTEM
4WD SYSTEM : System DescriptionINFOID:0000000006222224
 In AUTO mode, distribution of traction force is cont
rolled from 2WD status (0:100) to 4WD status (50:50)
according to signal from each sensor and switch.
 In accordance with fail-safe function, when system is malfunctioning, 4WD warning lamp on combination meter turns ON and 4WD control stops. For fail-safe function, refer to DLN-20, "
4WD SYSTEM : Fail-Safe".
 When a high load status continues for transfer assembly (transfer control actuator or transfer fluid), 4WD
control temporarily becomes 4H or 2WD status, according to protection function.
NOTE:
4WD system is not malfunctioning.
SYSTEM DIAGRAM
INPUT/OUTPUT SIGNAL
It transmits/receives each signal from the followi ng transfer control unit via CAN communication line.
JPDIE0272GB
Component parts Control signal
ABS actuator and electric unit (control unit) Transmits the following signals via CAN communication line to transfer control unit.
 Vehicle spee
d signal (ABS)
 Stop lamp switch signal (brake signal)
 ABS operation signal
 VDC operation signal
 TCS operation signal
ECM Transmits the following signals via CAN communication line to transfer control unit.
 Accelerator pedal position signal
 Engine speed signal
 Engine torque signal
Revision: 2010 May2011 QX56

SYSTEMDLN-19
< SYSTEM DESCRIPTION > [TRANSFER: ATX90A]
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4WD SHIFT SWITCH AND 4WD SHIFT INDICATOR LAMP
*1: Blinking 2 times/1 second
*2: “4HI” and “4LO” blink alternately.
CONDITION FOR TURN ON THE WARNING LAMP
TCM Transmits the following signals via CAN communication line to transfer control unit.
 Shift position signal
 Gear position signal
 Output shaft revolution signal
Steering angle sensor Transmits the following signals via CAN communication line to transfer control unit.
 Steering angle sensor signal
Combination meter Receives the following signals via CAN communication line from transfer control unit.
 4WD warning lamp signal
 ATP warning lamp signal
 4WD mode indicator signal
Component parts Control signal
4WD shift switch 4WD shift indicator lamp (in Information display) 4WD shift procedure
AUTO
1. Start the engine.
2. Turn the 4WD shift switch.
NOTE:
Mode can be switched between AU-
TO⇔4H while driving straight.
4H
↓↑
4WD status: 4H ⇔4L (Blinking)
*1*2
1. Start the engine.
2. Never drive the vehicle.
3. Shift A/T shift selector to N position.
4. Press and rotate 4WD shift switch
while depressing brake pedal.
CAUTION:
4WD mode does not switch when 4WD
shift switch is operated while the vehi-
cle is running or A/T shift selector is
shifted to any position other than neu-
tral.
4L
JPDIE0230ZZJPDIE0234ZZ
JPDIE0231ZZJPDIE0235ZZ
JPDIE0231ZZ
JPDIE0233ZZ
JPDIE0236ZZ
JPDIE0233ZZJPDIE0237ZZ
Revision: 2010 May2011 QX56

DLN-20
< SYSTEM DESCRIPTION >[TRANSFER: ATX90A]
SYSTEM
4WD Warning Lamp
 Turns ON when there is a malfunction in 4WD system. 4W
D warning lamp indicates the vehicle is in fail-safe
mode.
 Also turns ON when ignition switch is turned ON, fo r the purpose of lamp check. Turns OFF approximately
for 1 second after the engine starts if system is normal.
ATP Warning Lamp
When the A/T shift selector is in P position, the vehicle may move if the transfer case in neutral. ATP warning
lamp is turned on to indicate this condition to the driver.
CONDITION FOR OPERATE WARNING BUZZER
For preventing an incorrect operation during 4H ⇔4L switching, warning buzzer sounds from inside of transfer
control unit and warns the driver, when certain conditions are satisfied.
4WD SYSTEM : Fail-SafeINFOID:0000000006303692
 If any malfunction occurs in 4WD electrical system, and control unit detects the malfunction, 4WD warning
lamp on combination meter turns ON to indicate system malfunction.
 When 4WD warning lamp is ON, vehicle changes to rear-wheel drive or shifts to 4-wheel drive (front-wheels
still have some driving torque).
Condition 4WD warning lamp
Lamp check Turns ON when ignition switch is turned ON. Turns OFF ap-
prox. 1 second after the engine start.
4WD system malfunction ON
Protection function is activated due to heavy load to transfer assem-
bly. (4WD system is not malfunctioning.) Quick blinking: 2 times/second
(Blinking in approx. 1 minute and then turning OFF)
Large difference in diameter of front/rear tires Slow blinking: 1 time/2 seconds
(Continuing to blink until turning ignition switch OFF)
Other than above (system normal) OFF
Condition Warning buzzer
4WD shift status A/T shift selector Engine speed
4H⇔4L N range 350
− 1.600 rpm OFF
Under 350 rpm or over 1.600 rpm ON
Except N range Always
Revision: 2010 May2011 QX56