transmission fluid INFINITI QX56 2011 Factory Service Manual

BRC-14
< SYSTEM DESCRIPTION >[WITH VDC]
COMPONENT PARTS
ABS Actuator and Electric Unit (Control Unit)
INFOID:0000000006222561
Electric unit (control unit) is in tegrated with actuator and motor/accumulator assembly and comprehensively
controls VDC function, TCS function, AB S function, EBD function, hill start assist function or brake limited slip
differential function.
ELECTRIC UNIT (CONTROL UNIT)
 Brake fluid pressure, engine and transmission are controlled according to signals from each sensor.
 If malfunction is detected, the system enters fail-safe mode.
ACTUATOR
The following components are integrated with ABS actuator.
Motor/accumulator Assembly
Pump Operates the pump drive according to signals from ABS actuator and electric unit (control unit) by the motor.
Motor Operates the motor drive according to signals fr om ABS actuator and electric unit (control unit).
Accumulator
 The accumulator accumulates brake fluid conveyed by the motor and pump.
Motor Relay
Operates the motor ON/OFF according to signals fr om ABS actuator and electric unit (control unit).
Actuator Relay (Main Relay)
Operates each valve ON/OFF according to signals fr om ABS actuator and electric unit (control unit).
ABS IN Valve and ABS OUT Valve
Increases, holds or decreases the fluid pressure of each caliper according to signals from ABS actuator and
electric unit (control unit).
Cut Valve 1, Cut Valve 2
Shuts off the ordinary brake line from master cylinder to signals from ABS actuator and electric unit (control
unit).
Suction Valve 1
Suction Valve 1 switches the brake path to convey accu mulator pressure to the front system, according to a
signal transmitted from the ABS actuat or and electric unit (control unit).
Suction Valve 2
Suction valve 2 releases accumulator pressure, accord ing to a signal transmitted from the ABS actuator and
electric unit (control unit).
Control Pressure Sensor (models with Advanced Driver Assistance System)
Detects the brake fluid pressure of brake caliper side and transmits a signal to ABS actuator and electric unit
(control unit).
Accumulator Pressure Sensor
The accumulator pressure sensor detects brake fluid pressure accumulated in the accumulator and conveys
the detected result to the ABS act uator and electric unit (control unit).
Master cylinder Pressure Sensor
Detects the brake fluid pressure of master cylinder part and transmits a signal to ABS actuator and electric unit
(control unit).
Wheel Sensor and Sensor RotorINFOID:0000000006222562
NOTE:
 Wheel sensor and sensor rotor is integrated in wheel hub assembly.
 Never measure resistance and voltage value using a tester because sensor is active sensor.
Revision: 2010 May2011 QX56

BRC-16
< SYSTEM DESCRIPTION >[WITH VDC]
SYSTEM
SYSTEM
System DescriptionINFOID:0000000006222569
 The system switches fluid pressure of each brake caliper to increase, to hold or to decrease according to
signals from control unit in ABS actuator and electric unit (control unit). This control system is applied to
VDC function, TCS function, ABS func tion, EBD function, hill start assist function and brake limited slip dif-
ferential (BLSD) function
 Fail-safe function is available for each function and is activated by each function when system malfunction occurs.
 The adoption of the 4WD switch assembly (4WD sh ift switch and VDC OFF switch) enables to change the
control characteristics of the VDC function, the TCS function and the brake limited slip differential (BLSD)
function into an optimal characteristics, based on a st ate of the 4WD shift switch. (Models with 4WD system)
SYSTEM DIAGRAM
NOTE:
Transfer control unit is appli ed to models with 4WD system.
INPUT SIGNAL AND OUTPUT SIGNAL
Major signal transmission between each unit via communication lines is shown in the following table.
JPFIC0182GB
Component Signal description
Yaw rate/side/decel G sensor Mainly transmits the follo
wing signals to ABS actuator and elec tric unit (control unit) via com-
munication line
*1.
 Yaw rate signal
 Side G sensor signal
 Decel G sensor signal
ECM Mainly transmits the follo
wing signals to ABS actuator and elec tric unit (control unit) via CAN
communication.
 Accelerator pedal position signal
 Engine speed signal
Mainly receives the following si gnals from ABS actuator and electr ic unit (control unit) via CAN
communication.
 Target throttle position signal
Revision: 2010 May2011 QX56

BRC-30
< SYSTEM DESCRIPTION >[WITH VDC]
SYSTEM
Major signal transmission between each unit via communication lines is shown in the following table.
*1: Communication line between yaw rate/side/decal G s
ensor and ABS actuator and electric unit (control unit)
*2: Models with 4WD system
OPERATION CHARACTERISTICS
VDC Function That Prevents Oversteer Tendency
 During a cornering, brake force (brake fluid pressure) is applied on front wheel and rear wheel on the outer side of turn. Moment directing towards the outer side of turn is generated. Oversteer is prevented.
 Changing driving lane on a slippery road, when oversteer tendency is judged large, engine output is con- trolled as well as brake force (brake fluid pr essure) of 4 wheels. Oversteer tendency decreases.
VDC Function That Prevents Understeer Tendency
Component Signal description
Yaw rate/side/decel G sensor Mainly transmits the following si
gnals to ABS actuator and electric unit (control unit) via com-
munication line
*1.
 Yaw rate signal
 Side G sensor signal
 Decel G sensor signal
ECM Mainly transmits the following si
gnals to ABS actuator and electric unit (control unit) via CAN
communication.
 Accelerator pedal position signal
 Engine speed signal
Mainly receives the following signals from ABS actuator and electric unit (control unit) via CAN
communication.
 Target throttle position signal
TCM Mainly transmits the following si
gnals to ABS actuator and electric unit (control unit) via CAN
communication.
 Shift position signal
Transfer control unit
*2Mainly transmits the following si gnals to ABS actuator and electric unit (control unit) via CAN
communication.
 Current 4WD mode signal
Steering angle sensor Mainly transmits the following si
gnals to ABS actuator and electric unit (control unit) via CAN
communication.
 Steering angle sensor signal
Combination meter Mainly receives
the following signals from ABS actuator and electric unit (control unit) via CAN
communication.
 VDC warning lamp signal
 VDC OFF indicator lamp
JPFIC0135GB
JPFIC0136GB
Revision: 2010 May2011 QX56

SYSTEMBRC-31
< SYSTEM DESCRIPTION > [WITH VDC]
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BRC
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 During a cornering, brake force (brake fluid pressu re) is applied on front wheel and rear wheel on the inner
side of turn. Moment directing towards the inner side of turn is generated. Understeer is prevented.
 Applying braking during a cornering on a slippery road, when understeer tendency is judged large, engine
output is controlled as well as brake force (brake fluid pressure) of four wheels. Understeer tendency
decreases.
TCS FUNCTION
TCS FUNCTION : System DescriptionINFOID:0000000006222573
 Wheel spin status of drive wheel is detected by wheel sensor of 4
wheels. Engine output and transmission shift status is controlled
so that slip rate of drive wheels is in appropriate level. When wheel
spin occurs on drive wheel, ABS ac tuator and electric unit (control
unit) perform brake force control of LH and RH drive wheels (apply
brake force by increasing brake fluid pressure of drive wheel) and
decrease engine torque by engine torque control. Wheel spin
amount decreases. Engine torque is controlled to appropriate
level.
 TCS function can be switched to non-operational status (OFF) by
operating VDC OFF switch. In this case, VDC OFF indicator lamp
turns ON.
 TCS function is not operate when 4WD mode is “4L”. (Models with
4WD system)
 VDC warning lamp blinking while TCS function is in operation and indicates to the driver that the function is in operation.
 Slight vibrations are felt on the brake pedal and the operation noises occur, when TCS function operates. This is not a malfunc-
tion because it is caused by TCS function that is normally oper-
ated.
 CONSULT-III can be used to diagnose the system diagnosis.
 Fail-safe function is adopted. W hen a malfunction occurs in TCS
function, the control is suspended for VDC function, TCS function,
hill start assist function and brake limited slip differential (BLSD)
function. The vehicle status becomes the same as models without VDC function, TCS function, hill start
assist function and brake limited slip differential (B LSD) function. However, ABS function and EBD function
are operated normally. Refer to BRC-25, "
Fail-safe".
SYSTEM DIAGRAM
NOTE:
JPFIC0137GB
JPFIC0138GB
JPFIC0139GB
Revision: 2010 May2011 QX56

BRC-34
< SYSTEM DESCRIPTION >[WITH VDC]
SYSTEM
Transfer control unit is appli
ed to models with 4WD system.
INPUT SIGNAL AND OUTPUT SIGNAL
Major signal transmission between each unit via communication lines is shown in the following table.
*1: Communication line between yaw rate/side/decal G s ensor and ABS actuator and electric unit (control unit)
*2: Models with 4WD system
EBD FUNCTION
EBD FUNCTION : System DescriptionINFOID:0000000006222575
 By preventing rear wheel slip increase through rear wheel brake force (brake fluid pressure) control that is
electronically controlled when slight skip on front and r ear wheels are detected during braking, stability dur-
ing braking is improved.
JPFIC0184GB
Component Signal description
Yaw rate/side/decel G sensor Mainly transmits the following si
gnals to ABS actuator and electric unit (control unit) via com-
munication line
*1.
 Yaw rate signal
 Side G sensor signal
 Decel G sensor signal
Transfer control unit
*2Mainly transmits the following si gnals to ABS actuator and electric unit (control unit) via CAN
communication.
 Current 4WD mode signal
Combination meter Mainly receives
the following signals from ABS actuator and electric unit (control unit) via CAN
communication.
 ABS warning lamp signal
Revision: 2010 May2011 QX56

BRC-36
< SYSTEM DESCRIPTION >[WITH VDC]
SYSTEM
SYSTEM DIAGRAM
INPUT SIGNAL AND OUTPUT SIGNAL
Major signal transmission between each unit via communication lines is shown in the following table.
hill start assist FUNCTION
hill start assist FUNCTION : System DescriptionINFOID:0000000006222576
 This function maintains brake fluid pressure so that
the vehicle does not move backwards even if brake
pedal is released to depress accelerator pedal to start the vehicle while it is stopped on an uphill slope by
depressing brake pedal.
 This function operates when the vehicle is in stop status on a uphill slope of slope ratio 10% or more and
selector lever is in the position other than P or N.
 hill start assist function is only for the start aid. It maintains the brake fluid pressure for approx. 2 seconds after releasing the brake pedal, and then decreases the pressure gradually. If the vehicle can start by the
accelerator operation, the brake is released automatically and a smooth start can be performed.
 Fail-safe function is adopted. When a malfunction occurs in hill start assist function, the control is suspended
for VDC function, TCS function, hill start assist func tion and brake limited slip differential (BLSD) function.
The vehicle status becomes the same as models without VDC function, TCS function, hill start assist func-
tion and brake limited slip differential (BLSD) functi on. However, ABS function and EBD function are oper-
ated normally. Refer to BRC-25, "
Fail-safe".
JPFIC0144GB
Component Signal description
Combination meter Mainly receives
the following signals from ABS actuator and electric unit (control unit) via CAN
communication.
 Brake warning lamp signal
Revision: 2010 May2011 QX56

DLN-1
TRANSMISSION & DRIVELINE
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CONTENTS
DRIVELINE
TRANSFER: ATX90A
PRECAUTION ................ ...............................
6
PRECAUTIONS .............................................. .....6
Precaution for Supplemental Restraint System
(SRS) "AIR BAG" and "SEAT BELT PRE-TEN-
SIONER" ............................................................. ......
6
Precaution Necessary for Steering Wheel Rota-
tion after Battery Disconnect .....................................
6
Service Notice or Precautions for Transfer ...............7
PREPARATION ............................................8
PREPARATION .............................................. .....8
Special Service Tools .......................................... ......8
Commercial Service Tools ........................................8
SYSTEM DESCRIPTION .............................10
COMPONENT PARTS ................................... ....10
Component Parts Location .................................. ....10
Component Description ...........................................11
Transfer Control Unit ...............................................11
Transfer Control Actuator ........................................11
Transfer Hi-Lo Position Sensor ...............................12
Transfer Rotary Position Sensor .............................12
Transfer Lock Position Sensor ................................12
Transfer Fluid Temperature Sensor ........................12
STRUCTURE AND OPERATION .......................13
Sectional View ..................................................... ....13
Torque Split Mechanism .........................................13
SYSTEM .............................................................18
4WD SYSTEM ...........................................................18
4WD SYSTEM : System De scription ......................18
4WD SYSTEM : Fail-Safe ......................... ..............20
DIAGNOSIS SYSTEM (TRANSFER CON-
TROL UNIT) .................................................... ....
21
CONSULT-III Function ........................................ ....21
ECU DIAGNOSIS INFORMATION ..............24
TRANSFER CONTROL UNIT ...........................24
Reference Value .................................................. ....24
Fail-Safe ..................................................................28
DTC Inspection Priority Chart ..................................29
DTC Index ...............................................................29
WIRING DIAGRAM ......................................31
4WD SYSTEM .. ................................ .................31
Wiring Diagram .................................................... ....31
BASIC INSPECTION ...................................38
DIAGNOSIS AND REPAIR WORK FLOW .......38
Work Flow ............................................................ ....38
Diagnostic Work Sheet ............................................39
ADDITIONAL SERVICE WHEN REPLACING
TRANSFER CONTROL UNIT ...........................
41
Description ...............................................................41
Work Procedure .......................................................41
ADDITIONAL SERVICE WHEN REPLACING
TRANSFER ASSEMBLY ..................................
42
Description ...............................................................42
Work Procedure .......................................................42
TRANSFER LOCK POSITION SENSOR
LEARNING ....................................... .................
44
Description ........................................................... ....44
Work Procedure .......................................................44
TRANSFER ROTARY POSITION SENSOR
LEARNING ....................................... .................
46
Description ........................................................... ....46
Work Procedure .......................................................46
TRANSFER FLUID VISCOSITY LEARNING ....47
Description ...............................................................47
Revision: 2010 May2011 QX56

DLN-22
< SYSTEM DESCRIPTION >[TRANSFER: ATX90A]
DIAGNOSIS SYSTEM (T
RANSFER CONTROL UNIT)
ABS OPER [On/Off] X ABS operation status via CAN communication
line is displayed.
SAND MODE IND [On/Off] This indicator is not equipped, but it is dis-
played.
ROCK MODE IND [On/Off] This indicator is not equipped, but it is dis-
played.
SNOW MODE IND [On/Off] This indicator is not equipped, but it is dis-
played.
ONROAD MODE IND [On/Off] This indicator is not equipped, but it is dis-
played.
SAND MODE SW [On/Off] X This switch is not equipped, but it is displayed.
ROCK MODE SW [On/Off] X This switch is not equipped, but it is displayed.
SNOW MODE SW [On/Off] X This switch is not equipped, but it is displayed.
ONROAD MODE SW [On/Off] X This switch is not equipped, but it is displayed.
HI/LO POSI SEN 3 [On/Off] X Transfer Hi-Lo position sensor (3) status is dis-
played.
HI/LO POSI SEN 1 [On/Off] X Transfer Hi-Lo position sensor (1) status is dis-
played.
LOCK POSI SEN [OPEN/LOCK/BAT/UNLEAN/HI
TEMP/ERROR/GND] X
Transfer lock position sensor signal is dis-
played.
ATP IND [On/Off] Control status of ATP warning lamp is dis-
played.
4WD FAILLAMP [On/Off] X Control status of ATP warning lamp is dis-
played.
4WD MODE IND [4L/LOCK/AUTO] X Control status of 4WD mode indicator lamp is
displayed.
(LOCK means 4H of 4WD mode)
MOTOR DRIVE B [HI/LO/PWM] X Driving status of transfer motor is displayed.
(Reverse side)
MOTOR DRIVE A [HI/LO/PWM] X Driving status of transfer motor is displayed.
(Drive side)
FLUID TEMP SEN [V] X Temperature of transfer fluid is displayed.
MOTOR TEMP [V] X Temperature of transfer motor is displayed.
C/U POWER SUP [V] X Power supply voltage value of transfer control
unit is displayed.
MOTOR POWER SUP [V] X Power supply voltage value of transfer motor
unit is displayed.
ROTARY POSI SEN [%] X Transfer rotary position sensor signal is dis-
played.
THRTL POSI SEN [%] X X Throttle opening status via CAN communica-
tion line is displayed.
AT R SPEED [km/h] X Output shaft revolution speed via CAN commu-
nication line is displayed.
T/M GEAR [0 - 7] X Current transmission gear via CAN communi-
cation line is displayed.
COMPR VHCL SPEED [km/h] X Vehicle speed calculated by transfer control
unit is displayed.
VHCL/S SEN-FR [km/h] X Wheel speed (front) average calculated by
transfer control.
Monitor item (Unit)
SELECT MONITOR ITEM
Remarks
ECU INPUT
SIGNALS MAIN SIG-
NALS
Revision: 2010 May2011 QX56

DLN-116
< REMOVAL AND INSTALLATION >[TRANSFER: ATX90A]
TRANSFER HI-LO POSITION SENSOR
TRANSFER HI-LO POSITION SENSOR
Exploded ViewINFOID:0000000006222337
Removal and InstallationINFOID:0000000006222338
REMOVAL
1. Turn the ignition switch OFF.
2. Disconnect negative battery terminal.
CAUTION:
Wait for 5 seconds after turn ing ignition switch OFF.
3. Remove exhaust front tube (LH). Refer to EX-5, "
Removal and Installation".
4. Support transfer assembly and transmission assembly with a jack.
5. Remove front suspension rear cross member with a power tool. Refer to TM-208, "
4WD : Removal and
Installation".
6. Remove rear engine mounting cross member with a power tool. Refer to TM-208, "
4WD : Removal and
Installation".
7. Remove heat insulator of exhaust front tube (LH).
8. Lower jack to the position where the tr ansfer Hi-Lo position sensor can be removed.
9. Disconnect the transfer Hi-Lo position sensor connector.
10. Remove the transfer Hi-Lo position sensor.
11. Perform inspection after removal. Refer to DLN-116, "
Inspection".
INSTALLATION
Note the following, and install in the reverse order of removal.
 Never damage O-ring of transfer Hi-Lo position sensor.
 Perform inspection after installation. Refer to DLN-116, "
Inspection".
InspectionINFOID:0000000006222339
INSPECTION AFTER REMOVAL
Check the O-ring assembled transfer Hi-Lo position sens or for wear, crack and damage. Replace the transfer
Hi-Lo position sensor if there is malfunction.
INSPECTION AFTER INSTALLATION
After driving, check the surface fitting transfer Hi-Lo position sensor to transfer assembly for fluid leakage.
1. Transfer Hi-Lo position sensor 2. Transfer assembly
: Vehicle front
Refer to GI-4, "
Components" for symbols not described above.
JPDIE0282GB
Revision: 2010 May2011 QX56

TRANSFER LOCK POSITION SENSORDLN-119
< REMOVAL AND INSTALLATION > [TRANSFER: ATX90A]
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TRANSFER LOCK PO SITION SENSOR
Exploded ViewINFOID:0000000006222343
Removal and InstallationINFOID:0000000006222344
REMOVAL
1. Turn the ignition switch OFF.
2. Disconnect negative battery terminal.
CAUTION:
Wait for 5 seconds after turning ignition OFF.
3. Support transfer assembly and transmission assembly with a jack.
4. Remove rear engine mounting cross member with a power tool. Refer to TM-208, "
4WD : Removal and
Installation".
5. Lower jack to the position where the tr ansfer lock position sensor can be removed.
6. Disconnect the transfer lock position sensor connector.
7. Remove the transfer lock position sensor.
8. Perform inspection after removal. Refer to DLN-119, "
Inspection".
INSTALLATION
Note the following, and install in the reverse order of removal.
 Never damage O-ring of transfer lock position sensor.
 Perform inspection after installation. Refer to DLN-119, "
Inspection".
 When replacing the transfer lock position sensor, perform learning of transfer lock position sensor. Refer to
DLN-44, "
Work Procedure".
InspectionINFOID:0000000006222345
INSPECTION AFTER REMOVAL
Check the O-ring assembled transfer lock position sensor for wear, crack and damage. Replace the transfer
lock position sensor if there is malfunction.
INSPECTION AFTER INSTALLATION
After driving, check the surface fitting transfer lock position sensor to transfer assembly for fluid leakage.
1. Transfer lock position sensor 2. Transfer assembly
: Vehicle front
Refer to GI-4, "
Components" for symbols not described above.
JPDIE0284GB
Revision: 2010 May2011 QX56