belt INFINITI QX56 2011 Factory Workshop Manual

DEF-1
DRIVER CONTROLS
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SECTION DEF
A
B
DEF
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CONTENTS
DEFOGGER
PRECAUTION ................ ...............................3
PRECAUTIONS .............................................. .....3
Precaution for Supplemental Restraint System
(SRS) "AIR BAG" and "SEAT BELT PRE-TEN-
SIONER" ............................................................. ......
3
Precaution Necessary for Steering Wheel Rota-
tion after Battery Disconnect .....................................
3
SYSTEM DESCRIPTION ..............................5
COMPONENT PARTS ................................... .....5
Component Parts Location .................................. ......5
Component Description .............................................5
SYSTEM ..............................................................6
System Diagram .................................................. ......6
System Description ...................................................6
DIAGNOSIS SYSTEM (BCM) .............................7
COMMON ITEM ..................................................... ......7
COMMON ITEM : CONSULT-III Function (BCM -
COMMON ITEM) .......................................................
7
REAR WINDOW DEFOGGER ............................... ......8
REAR WINDOW DEFOGGER : CONSULT-III
Function (BCM - REAR DEFOGGER) ......................
8
DIAGNOSIS SYSTEM (IPDM E/R) .....................10
Diagnosis Description ......................................... ....10
CONSULT-III Function (IPDM E/R) .........................12
ECU DIAGNOSIS INFORMATION ..............15
BCM, IPDM E/R .............................................. ....15
List of ECU Reference ........................................ ....15
WIRING DIAGRAM ......................................16
REAR WINDOW DEFOGGER SYSTEM ........ ....16
Wiring Diagram ................................................... ....16
BASIC INSPECTION ...................................24
DIAGNOSIS AND REPAIR WORK FLOW .......24
Work Flow ............................................................ ....24
DTC/CIRCUIT DIAGNOSIS .........................25
REAR WINDOW DEFOGGER SWITCH ...........25
Component Function Check ................................ ....25
Diagnosis Procedure ...............................................25
REAR WINDOW DEFOGGER RELAY .............26
Description ...............................................................26
Component Function Check ....................................26
Diagnosis Procedure ...............................................26
REAR WINDOW DEFOGGER ..........................27
Description ...............................................................27
Component Function Check ....................................27
Diagnosis Procedure ...............................................27
DOOR MIRROR DEFOGGER ...........................29
Description ...............................................................29
Component Function Check ....................................29
Diagnosis Procedure ...............................................29
DRIVER SIDE DOOR MIRROR DEFOGGER ...30
Description ...............................................................30
Component Function Check ....................................30
Diagnosis Procedure ...............................................30
PASSENGER SIDE DOOR MIRROR DEFOG-
GER ...................................................................
31
Description ...............................................................31
Component Function Check ....................................31
Diagnosis Procedure ...............................................31
WIPER DEICER RELAY ...................................32
Component Function Check ....................................32
Diagnosis Procedure ...............................................32
Component Inspection .............................................33
WIPER DEICER ................................................34
Revision: 2010 May2011 QX56

PRECAUTIONSDEF-3
< PRECAUTION >
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DEF
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PRECAUTION
PRECAUTIONS
Precaution for Supplemental Restraint System (SRS) "AIR BAG" and "SEAT BELT
PRE-TENSIONER"
INFOID:0000000006349779
The Supplemental Restraint System such as “A IR BAG” and “SEAT BELT PRE-TENSIONER”, used along
with a front seat belt, helps to reduce the risk or severi ty 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 AIR BAG” and “SEAT BELT” of this
Service Manual.
WARNING:
• To avoid rendering the SRS inoper ative, which could increase the risk of personal injury or death in
the event of a collision that would result in air ba g inflation, all maintenance must be performed by
an authorized NISSAN/INFINITI dealer.
 Improper maintenance, including in correct removal and installation of the SRS, can lead to personal
injury caused by unintentional act ivation of the system. For removal of Spiral Cable and Air Bag
Module, see the “SRS AIR BAG”.
 Do not use electrical test equipm ent on any circuit related to the SRS unless instructed to in this
Service Manual. SRS wiring harnesses can be identi fied by yellow and/or orange harnesses or har-
ness connectors.
PRECAUTIONS WHEN USING POWER TOOLS (AIR OR ELECTRIC) AND HAMMERS
WARNING:
 When working near the Air Bag Diagnosis Sensor Unit or other Air Bag System sensors with the
ignition ON or engine running, DO NOT use air or electric power tools or strike near the sensor(s)
with a hammer. Heavy vibration could activate the sensor(s) and deploy the air bag(s), possibly
causing serious injury.
 When using air or electric power tools or hammers , always switch the ignition OFF, disconnect the
battery, and wait at least 3 minutes before performing any service.
Precaution Necessary for Steering Wh eel Rotation after Battery Disconnect
INFOID:0000000006299422
NOTE:
 Before removing and installing any control units, first tu rn the push-button ignition switch to the LOCK posi-
tion, then disconnect both battery cables.
 After finishing work, confirm that all control unit connectors are connected properly, then re-connect both
battery cables.
 Always use CONSULT-III to perform self-diagnosis as a part of each function inspection after finishing work.
If a DTC is detected, perform trouble diagnos is according to self-diagnosis results.
This vehicle is equipped with a push-button ignition switch and a steering lock unit.
If the battery is disconnect ed or discharged, the steering wheel will lock and cannot be turned.
If turning the steering wheel is required with the battery disconnected or discharged, follow the procedure
below before starting the repair operation.
OPERATION PROCEDURE
1. Connect both battery cables. NOTE:
Supply power using jumper cables if battery is discharged.
2. Turn the push-button ignition switch to ACC position. (At this time, the steering lock will be released.)
3. Disconnect both battery cables. The steering lock wil l remain released with both battery cables discon-
nected and the steering wheel can be turned.
4. Perform the necessary repair operation.
Revision: 2010 May2011 QX56

DLK-1
BODY EXTERIOR, DOORS, ROOF & VEHICLE SECURITY
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SECTION DLK
A
B
DLK
N
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CONTENTS
DOOR & LOCK
PRECAUTION ................ ...............................8
PRECAUTIONS .............................................. .....8
Precaution for Supplemental Restraint System
(SRS) "AIR BAG" and "SEAT BELT PRE-TEN-
SIONER" ............................................................. ......
8
Precaution Necessary for Steering Wheel Rota-
tion after Battery Disconnect .....................................
8
Precautions For Xenon Headlamp Service ...............9
Work ..........................................................................9
PREPARATION ...........................................10
PREPARATION .............................................. ....10
Commercial Service Tools .................................. ....10
SYSTEM DESCRIPTION .............................11
COMPONENT PARTS ................................... ....11
DOOR LOCK SYSTEM .............................................11
DOOR LOCK SYSTEM :
Component Parts Location ................................ ....
11
DOOR LOCK SYSTEM : Component Description ....12
AUTOMATIC BACK DOOR SYSTEM .......................13
AUTOMATIC BACK DOOR SYSTEM :
Component Parts Location ................................ ....
14
AUTOMATIC BACK DOOR SYSTEM :
Component Description ..........................................
15
SYSTEM (POWER DOOR LOCK SYSTEM) .....16
System Diagram .................................................. ....16
System Description .................................................16
SYSTEM (INTELLIGENT KEY SYSTEM) ..........18
INTELLIGENT KEY SYSTEM ...................................18
INTELLIGENT KEY SYSTEM : System Diagram ....18
INTELLIGENT KEY SYSTEM : System Descrip-
tion ..........................................................................
18
DOOR LOCK FUNCTION ...................................... ....19
DOOR LOCK FUNCTION : System Diagram ..........19
DOOR LOCK FUNCTION : System Description .....19
BACK DOOR OPEN FUNCTION ........................... ....21
BACK DOOR OPEN FUNCTION : System Dia-
gram ........................................................................
21
BACK DOOR OPEN FUNCTION : System De-
scription ...................................................................
21
REMOTE KEYLESS ENTRY FUNCTION ..................23
REMOTE KEYLESS ENTRY FUNCTION : Sys-
tem Diagram ........................................................ ....
23
REMOTE KEYLESS ENTRY FUNCTION : Sys-
tem Description ........................................................
23
KEY REMINDER FUNCTION ................................ ....25
KEY REMINDER FUNCTION : System Diagram ....25
KEY REMINDER FUNCTION : System Descrip-
tion ...........................................................................
26
WELCOME LIGHT FUNCTION ............................. ....26
WELCOME LIGHT FUNCTION : System Diagram
....
26
WELCOME LIGHT FUNCTION : System Descrip-
tion ...........................................................................
26
WARNING FUNCTION .......................................... ....27
WARNING FUNCTION : System Description ..........27
SYSTEM (AUTOMATIC BACK DOOR SYS-
TEM) ..................................................................
31
System Diagram .................................................. ....31
System Description ..................................................31
SYSTEM (INTEGRATED HOMELINK
TRANSMITTER) ................................................
37
System Description .............................................. ....37
DIAGNOSIS SYSTEM (BCM) ...........................38
COMMON ITEM ..................................................... ....38
COMMON ITEM : CONSULT-III Function (BCM -
COMMON ITEM) .....................................................
38
Revision: 2010 May2011 QX56

DLK-8
< PRECAUTION >
PRECAUTIONS
PRECAUTION
PRECAUTIONS
Precaution for Supplemental Restraint System (SRS) "AIR BAG" and "SEAT BELT
PRE-TENSIONER"
INFOID:0000000006225828
The Supplemental Restraint System such as “A IR BAG” and “SEAT BELT PRE-TENSIONER”, used along
with a front seat belt, helps to reduce the risk or severi ty 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 w hether the front occupants are belted or unbelted.
Information necessary to service the system safely is included in the “SRS AIR BAG” and “SEAT BELT” of this
Service Manual.
WARNING:
• To avoid rendering the SRS inopera tive, which could increase the risk of personal injury or death in
the event of a collision that would result in air bag inflation, all maintenance must be performed by
an authorized NISS AN/INFINITI dealer.
 Improper maintenance, including in correct removal and installation of the SRS, can lead to personal
injury caused by unintent ional activation of the system. For re moval of Spiral Cable and Air Bag
Module, see the “SRS AIR BAG”.
 Do not use electrical test equipmen t on any circuit related to the SRS unless instructed to in this
Service Manual. SRS wiring harnesses can be identi fied by yellow and/or orange harnesses or har-
ness connectors.
PRECAUTIONS WHEN USING POWER TOOLS (AIR OR ELECTRIC) AND HAMMERS
WARNING:
 When working near the Air Bag Diagnosis Sensor Unit or other Air Bag System sensors with the ignition ON or engine running, DO NOT use air or electric power tools or strike near the sensor(s)
with a hammer. Heavy vibration could activate the sensor(s) and deploy the air bag(s), possibly
causing serious injury.
 When using air or electric power tools or hammers , always switch the ignition OFF, disconnect the
battery, and wait at least 3 minu tes before performing any service.
Precaution Necessary for Steering W heel Rotation after Battery Disconnect
INFOID:0000000006225829
NOTE:
 Before removing and installing any control units, first tu rn the push-button ignition switch to the LOCK posi-
tion, then disconnect bot h battery cables.
 After finishing work, confirm that all control unit connectors are connected properly, then re-connect both
battery cables.
 Always use CONSULT-III to perform self-diagnosis as a part of each function inspection after finishing work.
If a DTC is detected, perform trouble diagnos is according to self-diagnosis results.
For vehicle with steering lock unit, if the battery is disconnected or discharged, the steering wheel will lock and
cannot be turned.
If turning the steering wheel is required with the bat tery disconnected or discharged, follow the operation pro-
cedure below before starting the repair operation.
OPERATION PROCEDURE
1. Connect both battery cables. NOTE:
Supply power using jumper cables if battery is discharged.
2. Turn the push-button ignition switch to ACC position. (At this time, the steering lock will be released.)
3. Disconnect both battery cables. The steering lock wi ll remain released with both battery cables discon-
nected and the steering wheel can be turned.
4. Perform the necessary repair operation.
Revision: 2010 May2011 QX56

DLN-1
TRANSMISSION & DRIVELINE
CEF
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SECTION DLN
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B
DLN
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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-6
< PRECAUTION >[TRANSFER: ATX90A]
PRECAUTIONS
PRECAUTION
PRECAUTIONS
Precaution for Supplemental Restraint S
ystem (SRS) "AIR BAG" and "SEAT BELT
PRE-TENSIONER"
INFOID:0000000006222209
The Supplemental Restraint System such as “A IR BAG” and “SEAT BELT PRE-TENSIONER”, used along
with a front seat belt, helps to reduce the risk or severi ty 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 w hether the front occupants are belted or unbelted.
Information necessary to service the system safely is included in the “SRS AIR BAG” and “SEAT BELT” of this
Service Manual.
WARNING:
• To avoid rendering the SRS inopera tive, which could increase the risk of personal injury or death in
the event of a collision that would result in air bag inflation, all maintenance must be performed by
an authorized NISS AN/INFINITI dealer.
 Improper maintenance, including in correct removal and installation of the SRS, can lead to personal
injury caused by unintent ional activation of the system. For re moval of Spiral Cable and Air Bag
Module, see the “SRS AIR BAG”.
 Do not use electrical test equipmen t on any circuit related to the SRS unless instructed to in this
Service Manual. SRS wiring harnesses can be identi fied by yellow and/or orange harnesses or har-
ness connectors.
PRECAUTIONS WHEN USING POWER TOOLS (AIR OR ELECTRIC) AND HAMMERS
WARNING:
 When working near the Air Bag Diagnosis Sensor Unit or other Air Bag System sensors with the ignition ON or engine running, DO NOT use air or electric power tools or strike near the sensor(s)
with a hammer. Heavy vibration could activate the sensor(s) and deploy the air bag(s), possibly
causing serious injury.
 When using air or electric power tools or hammers , always switch the ignition OFF, disconnect the
battery, and wait at least 3 minu tes before performing any service.
Precaution Necessary for Steering W heel Rotation after Battery Disconnect
INFOID:0000000006222210
NOTE:
 Before removing and installing any control units, first tu rn the push-button ignition switch to the LOCK posi-
tion, then disconnect bot h battery cables.
 After finishing work, confirm that all control unit connectors are connected properly, then re-connect both
battery cables.
 Always use CONSULT-III to perform self-diagnosis as a part of each function inspection after finishing work.
If a DTC is detected, perform trouble diagnos is according to self-diagnosis results.
For vehicle with steering lock unit, if the battery is disconnected or discharged, the steering wheel will lock and
cannot be turned.
If turning the steering wheel is required with the bat tery disconnected or discharged, follow the operation pro-
cedure below before starting the repair operation.
OPERATION PROCEDURE
1. Connect both battery cables. NOTE:
Supply power using jumper cables if battery is discharged.
2. Turn the push-button ignition switch to ACC position. (At this time, the steering lock will be released.)
3. Disconnect both battery cables. The steering lock wi ll remain released with both battery cables discon-
nected and the steering wheel can be turned.
4. Perform the necessary repair operation.
Revision: 2010 May2011 QX56

EC-1
ENGINE
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SECTION EC
A
EC
N
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CONTENTS
ENGINE CONTROL SYSTEM
VK56VD
PRECAUTION ................ ...............................
9
PRECAUTIONS .............................................. .....9
Precaution for Supplemental Restraint System
(SRS) "AIR BAG" and "SEAT BELT PRE-TEN-
SIONER" ............................................................. ......
9
Precaution for Procedure without Cowl Top Cover ......9
Precautions For Xenon Headlamp Service ...............9
On Board Diagnostic (OBD) System of Engine
and A/T ....................................................................
10
General Precautions ...............................................10
PREPARATION ...........................................14
PREPARATION .............................................. ....14
Special Service Tools .......................................... ....14
Commercial Service Tools ......................................14
SYSTEM DESCRIPTION .............................16
COMPONENT PARTS ................................... ....16
Component Parts Location .................................. ....16
Component Description ...........................................19
Accelerator Pedal Position Sensor ..........................21
Air Fuel Ratio (A/F) Sensor 1 ..................................21
ASCD Brake Switch & Stop Lamp Switch ...............21
ASCD Steering Switch ............................................21
ASCD Indicators ......................................................21
Battery Current Sensor (With Battery Tempera-
ture Sensor) ............................................................
22
Camshaft Position Sensor .......................................22
Crankshaft Position Sensor .....................................23
ECM ........................................................................23
Electric Throttle Control Actuator ............................23
Electrically-controlled cooling fan coupling .............24
Engine Coolant Temperature Sensor ......................25
Engine Oil Temperature Sensor ..............................25
EVAP Control System Pressure Sensor .................26
EVAP Canister Vent Control Valve .........................26
EVAP Canister Purge Volume Control Solenoid
Valve .................................................................... ....
26
Fuel Injector .............................................................26
Fuel Level Sensor ....................................................26
Fuel Pump Control Module ......................................27
Fuel Rail Pressure Sensor .......................................27
Fuel Tank Temperature Sensor ...............................27
Heated Oxygen Sensor 2 ........................................27
High Pressure Fuel Pump .......................................28
ICC Brake Switch & Stop Lamp Switch ...................29
ICC Steering Switch ................................................29
Ignition Coil With Power Transistor .........................29
Intake Valve Timing Control Solenoid Valve ...........29
Knock Sensor ...................................................... ....30
Low Fuel Pressure Sensor ......................................30
Low Pressure Fuel Pump ........................................30
Malfunction Indicator Lamp (MIL) ............................30
Manifold Absolute Pressure Sensor ........................31
Mass Air Flow Sensor (With Intake Air Tempera-
ture Sensor) .............................................................
31
Power Steering Pressure (PSP) Sensor ..................31
Refrigerant Pressure Sensor ............................... ....32
VVEL Actuator Motor ...............................................32
VVEL Actuator Motor Relay .....................................32
VVEL Control Module ..............................................32
VVEL Control Shaft Position Sensor .......................32
STRUCTURE AND OPERATION .....................33
Positive Crankcase Ventilation ................................33
On Board Refueling Vapor Recovery (ORVR) ........34
SYSTEM ............................................................35
ENGINE CONTROL SYSTEM ........................ ...........35
ENGINE CONTROL SYSTEM : System Diagram ....35
ENGINE CONTROL SYSTEM : System Descrip-
tion ...........................................................................
35
DIRECT INJECTION GASOLINE SYSTEM .......... ....36
DIRECT INJECTION GASOLINE SYSTEM :
System Diagram .....................................................
36
Revision: 2010 May2011 QX56

PRECAUTIONSEC-9
< PRECAUTION > [VK56VD]
C
D
E
F
G H
I
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K L
M A
EC
NP
O
PRECAUTION
PRECAUTIONS
Precaution for Supplemental
Restraint System (SRS) "AIR BAG" and "SEAT BELT
PRE-TENSIONER"
INFOID:0000000006219727
The Supplemental Restraint System such as “A IR BAG” and “SEAT BELT PRE-TENSIONER”, used along
with a front seat belt, helps to reduce the risk or severi ty 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 AIR BAG” and “SEAT BELT” of this
Service Manual.
WARNING:
• To avoid rendering the SRS inoper ative, which could increase the risk of personal injury or death in
the event of a collision that would result in air ba g inflation, all maintenance must be performed by
an authorized NISSAN/INFINITI dealer.
 Improper maintenance, including in correct removal and installation of the SRS, can lead to personal
injury caused by unintentional act ivation of the system. For removal of Spiral Cable and Air Bag
Module, see the “SRS AIR BAG”.
 Do not use electrical test equipm ent on any circuit related to the SRS unless instructed to in this
Service Manual. SRS wiring harnesses can be identi fied by yellow and/or orange harnesses or har-
ness connectors.
PRECAUTIONS WHEN USING POWER TOOLS (AIR OR ELECTRIC) AND HAMMERS
WARNING:
 When working near the Air Bag Diagnosis Sensor Unit or other Air Bag System sensors with the
ignition ON or engine running, DO NOT use air or electric power tools or strike near the sensor(s)
with a hammer. Heavy vibration could activate the sensor(s) and deploy the air bag(s), possibly
causing serious injury.
 When using air or electric power tools or hammers , always switch the ignition OFF, disconnect the
battery, and wait at least 3 minutes before performing any service.
Precaution for Procedur e without Cowl Top CoverINFOID:0000000006217650
When performing the procedure after removing cowl top cover, cover
the lower end of windshield with urethane, etc.
Precautions For Xenon Headlamp ServiceINFOID:0000000006217651
WARNING:
Comply with the follow ing warnings to prevent any serious accident.
 Disconnect the battery cable (neg ative terminal) or the power supply fuse before installing, remov-
ing, or touching the xenon headlamp (bulb included). The xenon headlamp contains high-voltage
generated parts.
 Never work with wet hands.
 Check the xenon headlamp ON-OFF status after assem bling it to the vehicle. Never turn the xenon
headlamp ON in other conditions. Connect th e power supply to the vehicle-side connector.
(Turning it ON outside the lamp case m ay cause fire or visual impairments.)
 Never touch the bulb glass immediately afte r turning it OFF. It is extremely hot.
PIIB3706J
Revision: 2010 May2011 QX56

EC-24
< SYSTEM DESCRIPTION >[VK56VD]
COMPONENT PARTS
Electric throttle control actuator consists of throttle bod
y, throttle valve, throttle control motor and throttle posi-
tion sensor.
THROTTLE CONTROL MOTOR
The throttle control motor is operated by the ECM and it opens and closes the throttle valve.
The current opening angle of the throttle valve is detected by the throttle position sensor. The throttle position
sensor provides feedback to the ECM, when opens/closes the throttle valve in response to driving conditions
via the throttle control motor.
THROTTLE POSITION SENSOR
The throttle position (TP) sensor responds to the throttle valve move-
ment.
The throttle position sensor has two sensors. These sensors are a
kind of potentiometer which transform the throttle valve position into
output voltage, and emit the voltage signal to the ECM. The ECM
judges the current opening angle of the throttle valve from these sig-
nals and controls the throttle valve opening angle in response to
driving conditions via the throttle control motor.
Electrically-controlled cooling fan couplingINFOID:0000000006217668
Electrically-controlled cooling fan coupling is integrat ed with a fan coupling, fan coupling driver, and fan speed
sensor, mounted to the fan pulley, and actuated by the dr ive belt to rotate the cooling fan at a speed suitable
for a driving condition.
JSBIA0270GB
PBIB0145E
JSBIA0289ZZ
Revision: 2010 May2011 QX56

EC-166
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
TROUBLE DIAGNOSIS - SPECIFICATION VALUE
1. Check for the cause of large engine friction. Refer to the following.
- Engine oil level is too high
- Engine oil viscosity
- Belt tension of power steering, alternat
or, A/C compressor, etc. is excessive
- Noise from engine
- Noise from transmission, etc.
2. Check for the cause of insufficient combustion. Refer to the following.
- Valve clearance malfunction
- Intake valve timing control function malfunction
- Camshaft sprocket installation malfunction, etc.
>> Repair or replace malfunctioning part, and then GO TO 27.
16.CHECK INTAKE SYSTEM
Check for the cause of uneven air flow through mass air flow sensor. Refer to the following.
 Crushed air ducts
 Malfunctioning seal of air cleaner element
 Uneven dirt of air cleaner element
 Improper specification of intake air system
Is the inspection result normal?
YES >> GO TO 18.
NO >> Repair or replace malfunctioning part, and then GO TO 17.
17.CHECK “A/F ALPHA-B1”, “A/F ALPHA-B2” AND “B/FUEL SCHDL”
Select “A/F ALPHA-B1”, “A/F ALPHA-B2” and “B/FUE L SCHDL” in “SPEC” of “DATA MONITOR” mode, and
check that each indication is within the SP value.
Is the measurement value within the SP value?
YES >> INSPECTION END
NO >> “B/FUEL SCHDL” is more, “A/F ALPHA-B1” and “A /F ALPHA-B2” are less than the SP value: GO
TO 18.
18.DISCONNECT AND RECONNECT MASS AIR FLOW SENSOR HARNESS CONNECTOR
1. Stop the engine.
2. Disconnect mass air flow sensor harness connector. Check pin terminal and connector for damage and then reconnect it again.
>> GO TO 19.
19.CHECK “A/F ALPHA-B1” AND “A/F ALPHA-B2”
1. Start engine.
2. Select “A/F ALPHA-B1” and “A/F ALPHA-B2” in “ SPEC” of “DATA MONITOR” mode, and check that each
indication is within the SP value.
Is the measurement value within the SP value?
YES >> Detect malfunctioning part of mass air flow sensor circuit and repair it. Refer to EC-201, "Diagno-
sis Procedure". Then GO TO 26.
NO >> GO TO 20.
20.CHECK “MAS A/F SE-B1”
Select “MAS A/F SE-B1” in “SPEC” of “DATA MONITOR” mode, and check that the indication is within the SP
value.
Is the measurement value within the SP value?
YES >> GO TO 21.
NO >> More than the SP value: Replace malfuncti oning mass air flow sensor, and then GO TO 26.
21.REPLACE ECM
1. Replace ECM.
2. Perform EC-143, "
Work Procedure".
Revision: 2010 May2011 QX56