2011 INFINITI QX56 power steering

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-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

DLN-148
< PRECAUTION >[FRONT FINAL DRIVE: R180A]
PRECAUTIONS
PRECAUTION
PRECAUTIONS
Precaution Necessary for Steering W
heel Rotation after Battery Disconnect
INFOID:0000000006222372
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.
5. When the repair work is completed, re-connect bot h battery cables. With the brake pedal released, turn
the push-button ignition switch from ACC position to ON position, then to LOCK position. (The steering
wheel will lock when the push-button igniti on switch is turned to LOCK position.)
6. Perform self-diagnosis check of all control units using CONSULT-III.
Precaution for Servicing Front Final DriveINFOID:0000000006222373
 Before starting diagnosis of the vehicle, understand the symptoms well. Perform correct and systematic
operations.
 Check for the correct installation status prior to re moval or disassembly. When matching marks are required,
be certain they do not interfere with the f unction of the parts they are applied to.
 Overhaul should be done in a clean work area, a dust proof area is recommended.
 Before disassembly, completely remove sand and mud from the exterior of the unit, preventing them from
entering into the unit during disassembly or assembly.
 Always use shop paper for cleaning the inside of components.
 Avoid using cotton gloves or a shop cloth to prevent the entering of lint.
 Check appearance of the disassembled parts for dam age, deformation, and abnormal wear. Replace them
with new ones if necessary.
 Gaskets, seals and O-rings should be replaced any time the unit is disassembled.
 Clean and flush the parts sufficiently and blow them dry.
 Be careful not to damage sliding surfaces and mating surfaces.
 When applying sealant, remove the old sealant from the mating surface; then remove any moisture, oil, and
foreign materials from the application and mating surfaces.
 In principle, tighten nuts or bolts gradually in severa l steps working diagonally from inside to outside. If a
tightening sequence is specified, observe it.
 During assembly, observe the specified tightening torque.
 Add new differential gear oil, petroleum jelly, or multi-purpose grease, as specified.
Revision: 2010 May2011 QX56

EC-1
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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

EC-6
DTC Logic ..............................................................364
Diagnosis Procedure .............................................365
P0527 COOLING FAN SPEED SENSOR .......367
DTC Logic ............................................................ ..367
Diagnosis Procedure .............................................367
Component Inspection (Cooling Fan Speed Sen-
sor) ........................................................................
369
P0550 PSP SENSOR .......................................371
DTC Logic ............................................................ ..371
Diagnosis Procedure .............................................371
Component Inspection (Power Steering Pressure
Sensor) ..................................................................
373
P0603 ECM POWER SUPPLY ........................374
DTC Logic ............................................................ ..374
Diagnosis Procedure .............................................374
P0605 ECM ......................................................376
DTC Logic ............................................................ ..376
Diagnosis Procedure .............................................376
P0607 ECM ......................................................378
DTC Logic ............................................................ ..378
Diagnosis Procedure .............................................378
P0611 ECM PROTECTION .............................379
Description ........................................................... ..379
DTC Logic ..............................................................379
Diagnosis Procedure .............................................379
P062B ECM .....................................................380
Description ........................................................... ..380
DTC Logic ..............................................................380
Diagnosis Procedure .............................................380
P0643 SENSOR POWER SUPPLY .................381
DTC Logic ............................................................ ..381
Diagnosis Procedure .............................................381
P0850 PNP SWITCH .......................................383
Description ........................................................... ..383
DTC Logic ..............................................................383
Component Function Check ..................................384
Diagnosis Procedure .............................................384
P1087, P1088 VVEL SYSTEM ........................386
DTC Logic ............................................................ ..386
Diagnosis Procedure .............................................386
P1089, P1092 VVEL CONTROL SHAFT PO-
SITION SENSOR .............................................
387
DTC Logic ............................................................ ..387
Diagnosis Procedure .............................................387
P1090, P1093 VVEL ACTUATOR MOTOR .....390
DTC Logic ............................................................ ..390
Diagnosis Procedure .............................................390
Component Inspection (VVEL ACTUATOR MO-
TOR ASSEMBLY) .................................................
392
Component Inspection (VVEL ACTUATOR
HOUSING ASSEMBLY) ......... ...............................
392
P1091 VVEL ACTUATOR MOTOR RELAY ... ..393
DTC Logic ............................................................ .393
Diagnosis Procedure .............................................393
Component Inspection (VVEL Actuator Motor Re-
lay) ....................................................................... .
395
P1148, P1168 CLOSED LOOP CONTROL .....396
DTC Logic ............................................................ .396
Diagnosis Procedure .............................................396
P1197 OUT OF GAS ........................................397
Description ........................................................... .397
DTC Logic .............................................................397
Diagnosis Procedure .............................................398
P1212 TCS COMMUNICATION LINE ..............399
Description ........................................................... .399
DTC Logic .............................................................399
Diagnosis Procedure .............................................399
P1217 ENGINE OVER TEMPERATURE .........400
DTC Logic ............................................................ .400
Component Function Check .................................400
Diagnosis Procedure .............................................401
P1220 FUEL PUMP CONTROL MODULE
(FPCM) ..............................................................
403
DTC Logic ............................................................ .403
Diagnosis Procedure .............................................403
Component Inspection (FPCM) ............................405
P1225 TP SENSOR ..........................................406
DTC Logic ............................................................ .406
Diagnosis Procedure .............................................406
P1226 TP SENSOR ..........................................407
DTC Logic ............................................................ .407
Diagnosis Procedure .............................................407
P1421 COLD START CONTROL .....................408
Description ........................................................... .408
DTC Logic .............................................................408
Diagnosis Procedure .............................................408
P1423, P1424 COLD START CONTROL ........410
Description ........................................................... .410
DTC Logic .............................................................410
Diagnosis Procedure .............................................410
P1550 BATTERY CURRENT SENSOR ...........412
DTC Logic ............................................................ .412
Diagnosis Procedure .............................................412
Component Inspection (Battery Current Sensor) ..414
P1551, P1552 BATTERY CURRENT SEN-
SOR ..................................................................
416
DTC Logic ............................................................ .416
Diagnosis Procedure .............................................416
Component Inspection (Battery Current Sensor) ..419
Revision: 2010 May2011 QX56

EC-7
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P1553 BATTERY CURRENT SENSOR ......... ..420
DTC Logic ........................................................... ..420
Diagnosis Procedure .............................................420
Component Inspection (Battery Current Sensor) ..423
P1554 BATTERY CURRENT SENSOR ...........424
DTC Logic ........................................................... ..424
Component Function Check ..................................424
Diagnosis Procedure .............................................425
Component Inspection (Battery Current Sensor) ..427
P1556, P1557 BATTERY TEMPERATURE
SENSOR ...........................................................
428
DTC Logic ........................................................... ..428
Diagnosis Procedure .............................................428
Component Inspection (Battery Temprature Sen-
sor) ........................................................................
430
P1564 ASCD STEERING SWITCH ..................431
DTC Logic ........................................................... ..431
Diagnosis Procedure .............................................431
Component Inspection (ASCD Steering Switch) ...433
P1564 ICC STEERING SWITCH ......................434
DTC Logic ........................................................... ..434
Diagnosis Procedure .............................................434
Component Inspection (ICC Steering Switch) .......436
P1568 ICC FUNCTION .....................................437
DTC Logic ........................................................... ..437
Diagnosis Procedure .............................................437
P1572 ASCD BRAKE SWITCH .......................438
DTC Logic ........................................................... ..438
Diagnosis Procedure .............................................439
Component Inspection (ASCD Brake Switch) .......442
Component Inspection (Stop Lamp Switch) ..........442
P1572 ICC BRAKE SWITCH ...........................443
DTC Logic ........................................................... ..443
Diagnosis Procedure .............................................444
Component Inspection (ICC Brake Switch) ...........445
Component Inspection (Stop Lamp Switch) ..........446
P1574 ASCD VEHICLE SPEED SENSOR ......447
Description .......................................................... ..447
DTC Logic .............................................................447
Diagnosis Procedure .............................................447
P1574 ICC VEHICLE SPEED SENSOR ..........449
Description .......................................................... ..449
DTC Logic .............................................................449
Diagnosis Procedure .............................................449
P1606 VVEL CONTROL MODULE ..................451
DTC Logic ........................................................... ..451
Diagnosis Procedure .............................................451
P1607 VVEL CONTROL MODULE ..................452
DTC Logic ........................................................... ..452
Diagnosis Procedure .............................................452
P1608 VVEL SENSOR POWER SUPPLY ......453
DTC Logic ............................................................ ..453
Diagnosis Procedure .............................................453
P1805 BRAKE SWITCH .................................455
DTC Logic ..............................................................455
Diagnosis Procedure .............................................455
Component Inspection (Stop Lamp Switch) ..........456
P2100, P2103 THROTTLE CONTROL MO-
TOR RELAY ....................................................
458
DTC Logic ..............................................................458
Diagnosis Procedure .............................................458
P2101 ELECTRIC THROTTLE CONTROL
FUNCTION ......................................................
460
Description ........................................................... ..460
DTC Logic ..............................................................460
Diagnosis Procedure .............................................460
Component Inspection ...........................................462
Special Repair Requirement ..................................463
P2118 THROTTLE CONTROL MOTOR .........464
DTC Logic ..............................................................464
Diagnosis Procedure .............................................464
Component Inspection (Electric Throttle Control
Motor) ....................................................................
465
P2119 ELECTRIC THROTTLE CONTROL
ACTUATOR .....................................................
466
DTC Logic ..............................................................466
Diagnosis Procedure .............................................466
P2122, P2123 APP SENSOR .........................468
DTC Logic ..............................................................468
Diagnosis Procedure .............................................468
Component Inspection (Accelerator Pedal Posi-
tion Sensor) ...........................................................
470
P2127, P2128 APP SENSOR .........................471
DTC Logic ..............................................................471
Diagnosis Procedure .............................................471
Component Inspection (Accelerator Pedal Posi-
tion Sensor) ...........................................................
474
P2135 TP SENSOR .........................................475
DTC Logic ..............................................................475
Diagnosis Procedure .............................................475
Component Inspection (Throttle Position Sensor) ..476
P2138 APP SENSOR ......................................478
DTC Logic ..............................................................478
Diagnosis Procedure .............................................478
Component Inspection (Accelerator Pedal Posi-
tion Sensor) ...........................................................
481
P2539, P2541, P2542 LOW FUEL PRES-
SURE SENSOR ...............................................
483
DTC Logic ..............................................................483
Diagnosis Procedure .............................................483
Component Inspection ...........................................485
Revision: 2010 May2011 QX56

EC-16
< SYSTEM DESCRIPTION >[VK56VD]
COMPONENT PARTS
SYSTEM DESCRIPTION
COMPONENT PARTS
Component Parts LocationINFOID:0000000006217656
ENGINE ROOM COMPARTMENT
ENGINE COMPARTMENT
1. IPDM E/R 2. ECM 3. Battery current sensor
(with battery temperature sensor)
4. Power steering pressure sensor 5. Alternator 6. Refrigerant pressure sensor
7. EVAP canister purge volume control solenoid valve 8. Electric throttle control actuator 9. Mass air flow sensor
(with intake air temperature sensor)
10. VVEL control module
JSBIA0293ZZ
Revision: 2010 May2011 QX56

COMPONENT PARTSEC-19
< SYSTEM DESCRIPTION > [VK56VD]
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Component DescriptionINFOID:0000000006217657
1. ASCD steering switch
ICC steering switch 2. Snow mode switch 3. Fuel level sensor unit and fuel pump
assembly (with fuel tank temperature
sensor)
4. Fuel pump control module (FPCM) 5. EVAP canister vent control valve 6. EVAP canister
7. EVAP control system pressure sen- sor 8. Stop lamp switch 9. ASCD brake switch
ICC brake switch
10. Accelerator pedal position sensor
JSBIA0606ZZ
Component Reference
ECM EC-23, "
ECM"
Malfunction indicator lamp (MIL)EC-30, "Malfunction Indicator Lamp (MIL)"
Ignition coil with power transistorEC-29, "Ignition Coil With Power Transistor"
Accelerator pedal position sensorEC-21, "Accelerator Pedal Position Sensor"
Mass air flow sensor
EC-31, "Mass Air Flow Sensor (With Intake Air Temperature Sen-
sor)"Intake air temperature sensor
Electric throttle control actuator
EC-23, "
Electric Throttle Control Actuator"Throttle control motor relay
Throttle control motor
Throttle position sensor
Crankshaft position sensorEC-23, "
Crankshaft Position Sensor"
Camshaft position sensorEC-22, "Camshaft Position Sensor"
Engine coolant temperature sensorEC-25, "Engine Coolant Temperature Sensor"
Revision: 2010 May2011 QX56