engine coolant INFINITI QX56 2011 Factory Owner's Manual

CAB MOUNTING INSULATORDLK-253
< REMOVAL AND INSTALLATION >
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 Remove brake tube from connector (front wheel well LH and RH side). Refer to BR-22, "FRONT :
Exploded View"
Vehicle center side
 Remove A/T control cable from manual lever. Refer to TM-178, "
Removal and Installation".
 Separate parking brake rear cable (LH and RH) from parking brake front cable. Refer to PB-5, "
Removal
and Installation".
 Remove engine room harness connector (frame assembly RH center side). Refer to PG-146, "
Engine
Room Harness"
- Remove harness connector protector.
- Disconnect chassis harness connector from engine room harness connector.
- Remove harness bracket bolt, and then remove engi ne room harness connector from frame assembly.
Vehicle rear side
 Remove EVAP hose (canister side).
 Remove rear final drive breather hose from air breather tube (body side). Refer to DLN-201, "
Removal
and Installation".
 Disconnect body harness connector from chassis harness connectors (frame assembly LH rear side).
Refer to PG-150, "
Body Harness"
6. Set safety stand to frame assembly. Release arm of 2-pole lift.
7. Remove cab mounting insulator bolts.
8. Set arm of 2-pole lift to body side sill portion of body.
9. Slowly lift 2-pole lift.
CAUTION:
 Check that there is no inte rference with the vehicle.
 Check that all connection points are disconnected.
10. Remove cab mounting insulator.
INSTALLATION
Note the following items, and then install in the reverse order of removal.
CAUTION:
 Before starting engine, check oil/fl uid levels including engine coolant and engine oil. If levels are
less than the required quantity, fill to the specified level. Refer to MA-10, "
Fluids and Lubricants".
 Warm up engine thoroughly to check that there is no leakage of fuel, exhaust gases, or any oil/fluids
including engine oil and engine coolant.
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-4
Component Inspection (Engine Coolant Tempera-
ture Sensor) ...........................................................
216
P0117, P0118 ECT SENSOR ..........................217
DTC Logic ............................................................ ..217
Diagnosis Procedure .............................................217
Component Inspection (Engine Coolant Tempera-
ture Sensor) ...........................................................
218
P0122, P0123 TP SENSOR .............................219
DTC Logic ............................................................ ..219
Diagnosis Procedure .............................................219
Component Inspection (Throttle Position Sensor) ..220
P0125 ECT SENSOR .......................................222
DTC Logic ............................................................ ..222
Diagnosis Procedure .............................................222
Component Inspection (Engine Coolant Tempera-
ture Sensor) ...........................................................
223
P0127 IAT SENSOR ........................................224
DTC Logic ............................................................ ..224
Diagnosis Procedure .............................................224
Component Inspection (Intake Air Temperature
Sensor) ..................................................................
225
P0128 THERMOSTAT FUNCTION .................226
DTC Logic ............................................................ ..226
Diagnosis Procedure .............................................227
Component Inspection (Engine Coolant Tempera-
ture Sensor) ...........................................................
227
P0130, P0150 A/F SENSOR 1 .........................228
DTC Logic ............................................................ ..228
Component Function Check ..................................229
Diagnosis Procedure .............................................230
P0131, P0151 A/F SENSOR 1 .........................232
DTC Logic ............................................................ ..232
Diagnosis Procedure .............................................233
P0132, P0152 A/F SENSOR 1 .........................235
DTC Logic ............................................................ ..235
Diagnosis Procedure .............................................236
P0133, P0153 A/F SENSOR 1 .........................238
DTC Logic ............................................................ ..238
Diagnosis Procedure .............................................239
P0137, P0157 HO2S2 ......................................243
DTC Logic ............................................................ ..243
Component Function Check ..................................244
Diagnosis Procedure .............................................245
Component Inspection (HO2 sensor 2) .................246
P0138, P0158 HO2S2 ......................................249
DTC Logic ............................................................ ..249
Component Function Check ..................................251
Diagnosis Procedure .............................................251
Component Inspection (HO2 sensor 2) .................254
P0139, P0159 HO2S2 .......................................257
DTC Logic ............................................................ .257
Component Function Check .................................258
Diagnosis Procedure .............................................259
Component Inspection (HO2 sensor 2) ................260
P0171, P0174 FUEL INJECTION SYSTEM
FUNCTION ........................................................
263
DTC Logic ............................................................ .263
Diagnosis Procedure .............................................264
P0172, P0175 FUEL INJECTION SYSTEM
FUNCTION ........................................................
267
DTC Logic ............................................................ .267
Diagnosis Procedure .............................................268
P0181 FTT SENSOR ........................................271
DTC Logic ............................................................ .271
Diagnosis Procedure .............................................271
Component Inspection (Fuel Tank Temperature
Sensor) .................................................................
273
P0182, P0183 FTT SENSOR ............................274
DTC Logic ............................................................ .274
Diagnosis Procedure .............................................274
Component Inspection (Fuel Tank Temperature
Sensor) .................................................................
275
P0190, P0192, P0193 FRP SENSOR ...............276
DTC Logic ............................................................ .276
Diagnosis Procedure .............................................276
Component Inspection (Fuel Rail Pressure Sen-
sor) ........................................................................
278
P0191 FRP SENSOR .......................................279
DTC Logic ............................................................ .279
Diagnosis Procedure .............................................279
Component Inspection (Fuel Rail Pressure Sen-
sor) ........................................................................
281
P0196 EOT SENSOR .......................................283
DTC Logic ............................................................ .283
Diagnosis Procedure .............................................284
Component Inspection (Engine Oil Temperature
Sensor) .................................................................
284
P0197, P0198 EOT SENSOR ...........................285
DTC Logic ............................................................ .285
Diagnosis Procedure .............................................285
Component Inspection (Engine Oil Temperature
Sensor) .................................................................
286
P0201, P0202, P0203, P0204, P0205, P0206,
P0207, P0208 INJECTOR ................................
287
DTC Logic ............................................................ .287
Diagnosis Procedure .............................................287
P0222, P0223 TP SENSOR ..............................288
DTC Logic ............................................................ .288
Diagnosis Procedure .............................................288
Component Inspection (Throttle Position Sensor) .289
Revision: 2010 May2011 QX56

EC-14
< PREPARATION >[VK56VD]
PREPARATION
PREPARATION
PREPARATION
Special Service ToolsINFOID:0000000006217654
Commercial Service ToolsINFOID:0000000006217655
Tool number
(Kent-Moore No.)
Tool nameDescription
KV10118400
(—)
Fuel tube adapter Measures fuel pressure
PBIB3043E
Tool name
(Kent-Moore No.)
Description
Leak detector
i.e.: (J-41416) Locates the EVAP leak
EVAP service port adapter
i.e.: (J-41413-OBD) Applys positive pressure through EVAP service
port
Fuel filler cap adapter
i.e.: (MLR-8382) Checks fuel tank vacuum relief valve opening
pressure
Socket wrench Removes and installs engine coolant temperature sensor
S-NT703
S-NT704
S-NT815
S-NT705
Revision: 2010 May2011 QX56

COMPONENT PARTSEC-17
< SYSTEM DESCRIPTION > [VK56VD]
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EXHAUST COMPARTMENT
1. VVEL actuator motor (bank 2) 2. Ignition coil (with power transistor)
and spark plug (bank 2)3. Camshaft position sensor (bank 2)
4. High pressure fuel pump 5. Intake valve timing control solenoid valve (bank 2)6. Electric-viscous fan assembly
7. Engine oil temperature sensor 8. Intake valve timing control solenoid valve (bank 1)9. Camshaft position sensor (bank 1)
10. Ignition coil (with power transistor) and spark plug (bank 1) 11. VVEL actuator motor (bank 1) 12. Low fuel pressure sensor
13. Positive crankcase ventilation (PCV) valve 14. Fuel injector (bank 2) 15. Knock sensor (bank 2)
16. Knock sensor (bank 1) 17. Fuel injector (bank 1) 18. Fuel rail pressure sensor
19. Manifold absolute pressure sensor 20. VVEL control shaft position sensor (bank 1)21. Crankshaft position sensor
22. Engine coolant temperature sensor 23. VVEL control shaft position sensor (bank 2)
A. Top view of the engine (View with intake manifold is re-
moved) B. Rear view of the engine
:Engine front
JPBIA3972ZZ
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

COMPONENT PARTSEC-25
< SYSTEM DESCRIPTION > [VK56VD]
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OEngine Coolant Temperature SensorINFOID:0000000006217669
The engine coolant temperature (ECT
) sensor is used to detect the
engine coolant temperature. The sensor modifies a voltage signal
from the ECM. The modified signal returns to the ECM as the engine
coolant temperature input. The sens or uses a thermistor which is
sensitive to the change in temperature. The electrical resistance of
the thermistor decreases as temperature increases.

*: These data are reference values and are measured between ECM terminals.
Engine Oil Temperature SensorINFOID:0000000006217670
The engine oil temperature sensor is used to detect the engine oil
temperature. The sensor modifies a voltage signal from the ECM.
The modified signal returns to the ECM as the engine oil tempera-
ture input. The sensor uses a ther mistor which is sensitive to the
change in temperature. The electrical resistance of the thermistor
decreases as temperature increases.

*: These data are reference values and are measured between ECM terminals. 1. Valve 2. Armature 3. Magnet Loop Element
4. Fan speed sensor 5. Coil 6. Silicon oil
SEF594K
Engine coolant temperature
[° C ( °F)] Voltage* (V) Resistance (k
Ω)
− 10 (14) 4.4 7.0 - 11.4
20 (68) 3.5 2.35 - 2.73
50 (122) 2.2 0.68 - 1.00
90 (194) 0.9 0.236 - 0.260
SEF012P
SEF594K
Engine oil temperature [° C ( °F)] Voltage* (V) Resistance (k
Ω)
–10 (14) 4.4 7.0 - 11.4 20 (68) 3.5 2.35 - 2.73
50 (122) 2.2 0.68 - 1.00
90 (194) 0.9 0.236 - 0.260
110 (230) 0.6 0.143 - 0.153
SEF012P
Revision: 2010 May2011 QX56

EC-28
< SYSTEM DESCRIPTION >[VK56VD]
COMPONENT PARTS
The heated oxygen sensor 2, after three way catalyst (manifold),
monitors the oxygen level in the exhaust gas on each bank.
Even if switching characteristics of
the air fuel ratio (A/F) sensor 1
are shifted, the air fuel ratio is c ontrolled to stoichiometric, by the sig-
nal from the heated oxygen sensor 2.
This sensor is made of ceramic zirconia. The zirconia generates volt-
age from approximately 1 V in richer conditions to 0 V in leaner con-
ditions.
Under normal conditions the heated ox ygen sensor 2 is not used for
engine control operation.
HEATED OXYGEN SENSOR 2 HEATER
Heated oxygen sensor 2 heater is integrated in the sensor.
The ECM performs ON/OFF control of the heated oxy gen sensor 2 heater corresponding to the engine speed,
amount of intake air and engine coolant temperature.
High Pressure Fuel PumpINFOID:0000000006217678
The high pressure fuel pump is installed at the front of the engine bank 2 side and activated by the camshaft.
ECM controls the high pressure fuel pump control sol enoid valve built into the high pressure fuel pump and
adjusts the amount of discharge by changing the suction timing of the low pressure fuel.
Operating Description
SEF327R
Engine speed Heated oxygen sensor 2 heater
Above 3,600 rpm OFF
Below 3,600 rpm after the following conditions are met.
 Engine: After warming up
 Keeping the engine speed between 3,500 and 4,000 rpm for 1 minute and at idle for 1 minute under no load ON
JSBIA0285GB
Revision: 2010 May2011 QX56

SYSTEMEC-37
< SYSTEM DESCRIPTION > [VK56VD]
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*1: This sensor is not used to control the engine system under normal conditions.
*2: ECM determines the start signal status by the signals of engine speed and battery voltage.
SYSTEM DESCRIPTION
The adoption of the direct fuel injection method enables
more accurate adjustment of fuel injection quantity by
injecting atomized high-pressure fuel directly into the cylinder. This method allows high-powered engine, low
fuel consumption, and emissions-reduction.
The amount of fuel injected from the fuel injector is determined by the ECM. The ECM controls the length of
time the valve remains open (injection pulse duration). T he amount of fuel injected is a program value in the
ECM memory. The program value is preset by engi ne operating conditions. These conditions are determined
by input signals (for engine speed and intake air and fuel rail pressure) from the crankshaft position sensor,
camshaft position sensor, mass air flow sensor and the fuel rail pressure sensor.
VARIOUS FUEL INJECTION INCREASE/DECREASE COMPENSATION
In addition, the amount of fuel injected is compens ated to improve engine performance under various operat-
ing conditions as listed below.
 During warm-up
 When starting the engine
 During acceleration
 Hot-engine operation
 When selector lever position is changed from N to D
 High-load, high-speed operation

 During deceleration
 During high engine speed operation
FUEL INJECTION CONTROL
Stratified-charge Combustion
Stratified-charge combustion is a combustion method wh ich enables extremely lean combustion by injecting
fuel in the latter half of a compression process, coll ecting combustible air-fuel around the spark plug, and form-
ing fuel-free airspace around the mixture.
Right after a start with the engine cold, the catalyst warm-up is accelerated by stratified-charge combustion.
Homogeneous Combustion
Sensor Input signal to ECM ECM function Actuator
Crankshaft position sensor Engine speed*
2
Fuel injection
& mixture ratio
controlFuel injector
Camshaft position sensor Camshaft position
Mass air flow sensor Amount of intake air
Intake air temperature sensor Intake air temperature
Engine coolant temperature sensor Engine coolant temperature
Air fuel ratio (A/F) sensor 1 Density of oxygen in exhaust gas
Fuel rail pressure sensor Fuel rail pressure
Throttle position sensor Throttle position
Accelerator pedal position sensor Accelerator pedal position
TCM Gear position
Battery
Battery voltage*
2
Knock sensor Engine knocking condition
Power steering pressure sensor Power steering operation
Heated oxygen sensor 2*
1Density of oxygen in exhaust gas
ABS actuator and electric unit (control unit) VDC/TCS operation command
A/C auto amp. A/C ON signal
Combination meter Vehicle speed
Revision: 2010 May2011 QX56

EC-38
< SYSTEM DESCRIPTION >[VK56VD]
SYSTEM
Homogeneous combustion is a combustion method that fuel
is injected during intake process so that combus-
tion occurs in the entire combustion chamber , as is common with conventional methods.
As for a start except for starts with the engine cold, homogeneous combustion occurs.
MIXTURE RATIO FEEDBACK CONTROL (CLOSED LOOP CONTROL)
The mixture ratio feedback system prov ides the best air-fuel mixture ratio for driveability and emission control.
The three way catalyst (manifold) can better reduce CO , HC and NOx emissions. This system uses A/F sen-
sor 1 in the exhaust manifold to monitor whether the engine operation is rich or lean. The ECM adjusts the
injection pulse width according to the sensor voltage signal. For more information about A/F sensor 1, refer to
EC-21, "
Air Fuel Ratio (A/F) Sensor 1". This maintains the mixture ratio within the range of stoichiometric
(ideal air-fuel mixture).
This stage is referred to as the closed loop control condition.
Heated oxygen sensor 2 is located downstream of the th ree way catalyst (manifold). Even if the switching
characteristics of A/F sensor 1 shift, the air-fuel ratio is controlled to stoichiometric by the signal from heated
oxygen sensor 2.
 Open Loop Control
The open loop system condition refers to when the ECM detects any of the following conditions. Feedback
control stops in order to maintain stabilized fuel combustion.
- Deceleration and acceleration
- High-load, high-speed operation
- Malfunction of A/F sensor 1 or its circuit
- Insufficient activation of A/F sensor 1 at low engine coolant temperature
- High engine coolant temperature
- During warm-up
- After shifting from N to D
- When starting the engine
MIXTURE RATIO SELF-LEARNING CONTROL
The mixture ratio feedback control system monitors t he mixture ratio signal transmitted from A/F sensor 1.
This feedback signal is then sent to the ECM. The ECM c ontrols the basic mixture ratio as close to the theoret-
ical mixture ratio as possible. However, the basic mi xture ratio is not necessarily controlled as originally
designed. Both manufacturing differences (i.e., mass ai r flow sensor hot wire) and characteristic changes dur-
ing operation (i.e., fuel injector clogging) directly affect mixture ratio.
Accordingly, the difference between the basic and theoretical mixture ratios is monitored in this system. This is
then computed in terms of “injection pulse duration” to automatically compensate for the difference between
the two ratios.
“Fuel trim” refers to the feedback compensation value co mpared against the basic injection duration. Fuel trim
includes “short-term fuel trim” and “long-term fuel trim”.
“Short term fuel trim” is the short-term fuel compensati on used to maintain the mixture ratio at its theoretical
value. The signal from A/F sensor 1 indicates whether the mixture ratio is RICH or LEAN compared to the the-
oretical value. The signal then triggers a reduction in fuel volume if the mixture ratio is rich, and an increase in
fuel volume if it is lean.
“Long-term fuel trim” is overall fuel compensation carri ed out over time to compensate for continual deviation
of the “short-term fuel trim” from the central value. Continual deviation will occur due to individual engine differ-
ences, wear over time and changes in the usage environment.
FUEL INJECTION TIMING
Sequential Direct Injection Gasoline System
PBIB2793E
Revision: 2010 May2011 QX56