diagram INFINITI QX56 2011 Factory Service Manual

POWER SUPPLY AND GROUND CIRCUITDLN-95
< DTC/CIRCUIT DIAGNOSIS > [TRANSFER: ATX90A]
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2. Disconnect 4WD switch assembly harness connector.
3. Check the voltage between 4WD switch assembly harness connector and ground.
4. Turn the ignition switch ON. CAUTION:
Never start the engine.
5. Check the voltage between 4WD switch assembly harness connector and ground.
Is the inspection result normal?
YES >> GO TO 9.
NO >> GO TO 8.
8.CHECK 4WD SWITCH ASSEMBLY POWER SUPPLY (2)
1. Turn the ignition switch OFF.
2. Check the 10A fuse (#13).
3. Disconnect fuse block (J/B) harness connector.
4. Check the continuity between transfer control unit harness connector and IPDM E/R harness connector.
5. Check the continuity between transfer control unit harness connector and the ground.
Is the inspection result normal?
YES >> Perform the trouble diagnosis for ignition power supply circuit. Refer to PG-89, "Wiring Diagram -
IGNITION POWER SUPPLY -".
NO >> Repair or replace error-detected parts.
9.CHECK TRANSFER CONTROL UNIT GROUND
1. Turn the ignition switch OFF.
2. Check the voltage between transfer control unit harness connector and ground.
3. Check the continuity between transfer control unit harness connector and ground.
4WD switch assembly — Voltage
Connector Terminal
M54 12 Ground Approx. 0 V
4WD switch assembly — Voltage
Connector Terminal
M54 12 Ground Battery voltage
Fuse block (J/B) 4WD switch assembly Continuity
Connector Terminal Connector Terminal
M3 10C M54 12 Existed
4WD switch assembly —Continuity
Connector Terminal
M54 12 Ground Not existed
Transfer control unit — Voltage
Connector Terminal
E60 44
Ground Approx. 0 V
46
Transfer control unit —Continuity
Connector Terminal
E60 44
Ground Existed
46
Revision: 2010 May2011 QX56

EC-1
ENGINE
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SECTION EC
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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-2
DIRECT INJECTION GASOLINE SYSTEM : Sys-
tem Description .......................................................
36
FUEL PRESSURE CONTROL ..................................39
FUEL PRESSURE CONTROL : System Diagram
...
39
FUEL PRESSURE CONTROL : System Descrip-
tion ..........................................................................
39
COOLING FAN CONTROL .................................... ...40
COOLING FAN CONTROL : System Diagram .......41
COOLING FAN CONTROL : System Description ...41
ELECTRIC IGNITION SYST EM ................................41
ELECTRIC IGNITION SYSTEM :
System Diagram ................................................. ...
42
ELECTRIC IGNITION SYSTEM : System De-
scription ..................................................................
42
INTAKE VALVE TIMING CONTROL ..................... ...43
INTAKE VALVE TIMING CONTROL : System Di-
agram .....................................................................
43
INTAKE VALVE TIMING CONTROL : System De-
scription ..................................................................
43
VVEL SYSTEM ....................................... ...................43
VVEL SYSTEM : System Dia gram ........................44
VVEL SYSTEM : System De scription .....................44
EVAPORATIVE EMISSION SYSTEM .................... ...45
EVAPORATIVE EMISSION SYSTEM : System
Diagram ..................................................................
45
EVAPORATIVE EMISSION SYSTEM : System
Description ..............................................................
45
AIR CONDITIONING CUT CONTROL ................... ...46
AIR CONDITIONING CUT CONTROL : System
Diagram ..................................................................
47
AIR CONDITIONING CUT CONTROL : System
Description ..............................................................
47
AUTOMATIC SPEED CONTROL DEVICE (ASCD) ...47
AUTOMATIC SPEED CONTROL DEVICE (AS-
CD) : System Diagram ............................................
48
AUTOMATIC SPEED CONTROL DEVICE (AS-
CD) : System Description .......................................
48
CAN COMMUNICATION ........................................ ...48
CAN COMMUNICATION : System Description ......48
OPERATION ................................................... ...49
AUTMATIC SPEED CONTROL DEVICE (ASCD) . ...49
AUTMATIC SPEED CONTROL DEVICE (ASCD)
: Switch Name and Function ...................................
49
ON BOARD DIAGNOSTIC (OBD) SYSTEM .....51
Diagnosis Description .......................................... ...51
GST (Generic Scan Tool) .......................................51
DIAGNOSIS SYSTEM (ECM) ............................52
DIAGNOSIS DESCRIPTION .................................. ...52
DIAGNOSIS DESCRIPTION : 1st Trip Detection
Logic and Two Trip Detection Logic ........................
52
DIAGNOSIS DESCRIPTION : DTC and Freeze
Frame Data .............................................................
52
DIAGNOSIS DESCRIPTION : Counter System ......53
DIAGNOSIS DESCRIPTION : Driving Pattern ........58
DIAGNOSIS DESCRIPTION : System Readiness
Test (SRT) Code .................................................. ...
58
DIAGNOSIS DESCRIPTION : Malfunction Indica-
tor Lamp (MIL) ..................................................... ...
60
On Board Diagnosis Function .................................60
CONSULT-III Function ............................................63
ECU DIAGNOSIS INFORMATION .............72
ECM ................................................................ ...72
Reference Value .................................................. ...72
Fail-safe ..................................................................93
DTC Inspection Priority Chart .................................96
DTC Index ...............................................................98
Test Value and Test Limit ..................................104
VVEL CONTROL MODULE .............................110
Reference Value .................................................. .110
WIRING DIAGRAM ...................................114
ENGINE CONTROL SYSTEM ........................ ..114
Wiring Diagram .................................................... .114
BASIC INSPECTION .................................135
DIAGNOSIS AND REPAIR WORKFLOW ...... ..135
Work Flow ............................................................ .135
Diagnostic Work Sheet .........................................138
BASIC INSPECTION ...................................... ..139
Work Procedure ................................................... .139
ADDITIONAL SERVICE WHEN REPLACING
ECM ..................................................................
143
Description ........................................................... .143
Work Procedure ....................................................143
ADDITIONAL SERVICE WHEN REPLACING
VVEL CONTROL MODULE .............................
144
Description ........................................................... .144
Work Procedure ....................................................144
VIN REGISTRATION ........................................145
Description ........................................................... .145
Work Procedure ....................................................145
ACCELERATOR PEDAL RELEASED POSI-
TION LEARNING ............................................ ..
146
Description ........................................................... .146
Work Procedure ....................................................146
THROTTLE VALVE CLOSED POSITION
LEARNING .......................................................
147
Description ........................................................... .147
Revision: 2010 May2011 QX56

SYSTEMEC-35
< SYSTEM DESCRIPTION > [VK56VD]
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SYSTEM
ENGINE CONTROL SYSTEM
ENGINE CONTROL SYSTEM : System DiagramINFOID:0000000006217697
ENGINE CONTROL SYSTEM : System DescriptionINFOID:0000000006217698
ECM controls the engine by various functions.
JSBIA0590GB
Revision: 2010 May2011 QX56

EC-36
< SYSTEM DESCRIPTION >[VK56VD]
SYSTEM
DIRECT INJECTION GASOLINE SYSTEM
DIRECT INJECTION GASOLINE
SYSTEM : System DiagramINFOID:0000000006217699
DIRECT INJECTION GASOLINE SY STEM : System DescriptionINFOID:0000000006217700
INPUT/OUTPUT SIGNAL CHART
Function Reference
Fuel injection control EC-36, "
DIRECT INJECTION GASOLINE
SYSTEM : System De-
scription"
Fuel pressure control EC-39, "FUEL PRESSURE CONTROL : System Description"
Cooling fan controlEC-41, "COOLING FAN CONTROL : System Description"
Electric ignition controlEC-42, "ELECTRIC IGNITION SYSTEM : System Description"
Intake valve timing controlEC-43, "INTAKE VALVE TIMING CONTROL : System Description"
VVEL (Variable Valve Event & Lift) EC-44, "VVEL SYSTEM : System Description"
Evaporative emissionEC-45, "EVAPORATIVE EMISSION SYSTEM : System Descrip-
tion"
Air conditioning cut controlEC-47, "AIR CONDITIONING CUT CONT
ROL : System Descrip-
tion"
ASCD (Auto speed control device) EC-48, "AUTOMATIC SPEED CONTROL DEVICE (ASCD) : Sys-
tem Description"
Power generation voltage variable controlCHG-7, "POWER GENERATION VOLTAGE VARIABLE CON-
TROL SYSTEM : System Description"
JSBIA0471GB
Revision: 2010 May2011 QX56

SYSTEMEC-39
< SYSTEM DESCRIPTION > [VK56VD]
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Fuel is injected into each cylinder during each engine cycle accord-
ing to the ignition order.
STRATIFIED-CHARGE START CONTROL
The use of the stratified-charge combustion met
hod enables emissions-reduction when starting the engine
with engine coolant temperature between 5 °C (41 °F) and 40 °C (104 °F).
FUEL SHUT-OFF
Fuel to each cylinder is shut-off during deceleration, operation of the engine at excessively high speed or oper-
ation of the vehicle at excessively high speed.
FUEL PRESSURE CONTROL
FUEL PRESSURE CONTROL : System DiagramINFOID:0000000006217701
FUEL PRESSURE CONTROL : System DescriptionINFOID:0000000006217702
INPUT/OUTPUT SIGNAL CHART
JSBIA0407GB
JSBIA0315GB
Sensor Input signal to ECM ECM function Actuator
Crankshaft position sensor Engine speed
Fuel injection
& mixture ratio
controlHigh pressure fuel pump
Camshaft position sensor Camshaft position
Fuel rail pressure sensor Fuel rail pressure
Low fuel pressure sensor Low fuel pressure
Engine coolant temperature sensor Engine coolant temperature
Throttle position sensor Throttle position
Accelerator pedal position sensor Accelerator pedal position
Battery Battery voltage
Revision: 2010 May2011 QX56

SYSTEMEC-41
< SYSTEM DESCRIPTION > [VK56VD]
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COOLING FAN CONTROL : System DiagramINFOID:0000000006217703
COOLING FAN CONTROL : System DescriptionINFOID:0000000006217704
INPUT/OUTPUT SIGNAL CHART
*1: The ECM determines the engine speed by the signals of crankshaft position and camshaft position.
*2: This signal is sent to ECM via the CAN communication line.
SYSTEM DESCRIPTION
 Based on a signal transmitted from each sensor, ECM calc
ulates a target fan speed responsive to a driving
condition. In addition, ECM calculates a fan pulley speed according to an engine speed and transmits a cool-
ing fan request signal to IPDM E/R via the CAN comm unication line to satisfy the target fan speed. Then,
IPDM E/R transmits ON/OFF pulse duty signal to electrically-controlled cooling fan coupling.
The cooling fan speed sensor detects a cooling f an speed and transmits the detection result to ECM.
 ECM judges the start signal state from the engine speed signal and battery voltage.
ELECTRIC IGNITION SYSTEM
JSBIA0237GB
Sensor Input signal to ECM ECM function Actuator
Crankshaft position sensor Engine speed*
1
Cooling fan speed request
signal*2
IPDM E/R
↓
Electrically-controlled cooling fan
coupling
Camshaft position sensor Camshaft position
Engine coolant temperature sensor Engine coolant temperature
Refrigerant pressure sensor Refrigerant pressure
Intake air temperature sensor Intake air temperature
Battery Battery voltage
Combination meter
Vehicle speed signal*
2
BCMA/C switch signal*2
Cooling fan speed sensor Cooling fan speed
Revision: 2010 May2011 QX56

EC-42
< SYSTEM DESCRIPTION >[VK56VD]
SYSTEM
ELECTRIC IGNITION SYSTEM : System Diagram
INFOID:0000000006217705
ELECTRIC IGNITION SYSTEM : System DescriptionINFOID:0000000006217706
INPUT/OUTPUT SIGNAL CHART
*1: ECM determines the start signal status by the signals of engine speed and battery voltage.
*2: This signal is sent to the ECM via the CAN communication line.
SYSTEM DESCRIPTION
Ignition order: 1 - 8 - 7 - 3 - 6 - 5 - 4 - 2
The ignition timing is controlled by the ECM to maintain the best air-fuel ratio for every running condition of the
engine. The ignition timing data is stored in the ECM.
The ECM receives information such as the injection pulse width and camshaft position sensor signal. Comput-
ing this information, ignition signals are transmitted to the power transistor.
During the following conditions, the ignition timing is re vised by the ECM according to the other data stored in
the ECM.
 At starting
 During warm-up
 At idle
 At low battery voltage
 During acceleration
The knock sensor retard system is designed only for emergencies. The basic ignition timing is programmed
within the anti-knocking zone, if recommended fuel is used under dry conditions. The retard system does not
operate under normal driving conditions. If engine knocking occurs, the knock sensor monitors the condition.
The signal is transmitted to the ECM. The ECM retards the ignition timing to eliminate the knocking condition.
JPBIA3271GB
Sensor Input signal to ECM ECM function Actuator
Crankshaft position sensor Engine speed*
1
Piston position
Ignition timing
controlIgnition coil
(with power transistor)
Camshaft position sensor
Mass air flow sensor Amount of intake air
Engine coolant temperature sensor Engine coolant temperature
Throttle position sensor Throttle position
Accelerator pedal position sensor Accelerator pedal position
TCM Gear position
Battery
Battery voltage*
1
Knock sensor Engine knocking condition
Combination meterVehicle speed*
2
Revision: 2010 May2011 QX56

SYSTEMEC-43
< SYSTEM DESCRIPTION > [VK56VD]
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INTAKE VALVE TIMING CONTROL
INTAKE VALVE TIMING CONTROL : System DiagramINFOID:0000000006217707
INTAKE VALVE TIMING CONT
ROL : System DescriptionINFOID:0000000006217708
INPUT/OUTPUT SIGNAL CHART
*: This signal is sent to the ECM via the CAN communication line.
SYSTEM DESCRIPTION
This mechanism hydraulically controls cam phases c ontinuously with the fixed operating angle of the intake
valve.
The ECM receives signals such as crankshaft posit ion, camshaft position, engine speed, and engine coolant
temperature. Then, the ECM sends ON/OFF pulse duty signals to the intake valve timing control solenoid
valve depending on driving status. This makes it possible to control the shut/open timing of the intake valve to
increase engine torque in low/mid speed range and output in high speed range.
VVEL SYSTEM
JMBIA2174GB
Sensor Input signal to ECM ECM function Actuator
Crankshaft position sensor Engine speed and piston position
Intake valve timing
controlIntake valve timing control
solenoid valve
Camshaft position sensor
Engine oil temperature sensor Engine oil temperature
Engine coolant temperature sensor Engine coolant temperature
Combination meter Vehicle speed*
PBIB3276E
Revision: 2010 May2011 QX56

EC-44
< SYSTEM DESCRIPTION >[VK56VD]
SYSTEM
VVEL SYSTEM : System Diagram
INFOID:0000000006217709
VVEL SYSTEM : System DescriptionINFOID:0000000006217710
INPUT/OUTPUT SIGNAL CHART
SYSTEM DESCRIPTION
JSBIA0539GB
Sensor Input signal to ECM ECM function Actuator
Camshaft position sensor
Crankshaft position sensor Engine speed and piston position
VVEL controlVVEL control module
↓
VVEL actuator motor assem-
bly
Accelerator pedal position sensor Accelerator pedal position
VVEL control shaft
position sensor
↓
VVEL control module Control shaft actual angle
1. VVEL control shaft position
sensor 2. Drive shaft 3. Link A
4. Eccentric cam 5. Output cam 6. Valve lifter
7. Intake valve 8. Intake camshaft sprocket 9. Control shaft
10. Ball screw shaft 11. Ball screw nu t 12. VVEL actuator motor assembly
13. Rocker arm 14. Link B
JSBIA0463ZZ
Revision: 2010 May2011 QX56