coolant INFINITI QX56 2007 Factory Owner's Guide

CO-20
< SERVICE INFORMATION >
THERMOSTAT AND WATER PIPING
THERMOSTAT AND WATER PIPING
Removal and InstallationINFOID:0000000003531576
REMOVAL
Removal of Thermostat
1. Drain engine coolant from the radiator. Refer to CO-9, "Changing Engine Coolant".
CAUTION:
Perform when engine is cold.
2. Remove the air duct and resonator assembly. Refer to EM-15, "
Removal and Installation".
3. Remove the engine room cover using power tool.
4. Disconnect the water suction hose from the water inlet.
5. Remove the water inlet and thermostat.
Removal of Thermostat Housing, Water Outlet and Heater Pipe
1. Remove the intake manifold. Refer to EM-17, "Removal and Installation".
2. Remove the thermostat housing, water outlet and heater pipe.
Removal of Water Cut Valve
1. Drain the engine coolant from the radiator. Refer to CO-9, "Changing Engine Coolant".
CAUTION:
Perform when the engine is cold.
2. Remove the air duct and resonator assembly. Refer to EM-15, "
Removal and Installation".
KBIA2501E
1. Heater pipe 2. Gasket 3. Water outlet
4. Gasket 5. O-ring 6. O-ring
7. Thermostat housing 8. Rubber ring 9. Thermostat
10. Water inlet 11. Water suction hose 12. Water suction pipe
13. Gasket 14. Heater pipe

THERMOSTAT AND WATER PIPING
CO-21
< SERVICE INFORMATION >
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3. Remove the engine room cover using power tool.
4. Disconnect the heater hose (heater core side).
5. Remove the heater hose bracket.
6. Disconnect the water cut valve connector.
7. Remove the water cut valve.
INSPECTION AFTER REMOVAL
• Place a thread so that it is caught in the valve of the thermostat.
Immerse fully in a container filled with water. Heat while stirring.
• The valve opening temperature is the temperature at which the
valve opens and falls from the thread.
• Continue heating. Check the full-open lift amount.
• After checking the full-open lift amount, lower the water tempera-
ture and check the valve closing temperature.
Standard values:
INSTALLATION
Installation is in the reverse order of removal.
Installation of Thermostat
• Install the thermostat with the whole circumference of each flange
part fit securely inside the rubber ring as shown.
• Install the thermostat with the jiggle valve facing upwards.
Installation of Water Outlet Pipe and Heater Pipe
First apply a neutral detergent to the O-rings, then quickly insert the insertion parts of the water outlet pipe and
heater pipe into the installation holes.
INSPECTION AFTER INSTALLATION
• Check for leaks of the engine coolant. Refer to CO-9, "Inspection".
• Start and warm up the engine. Visually check for leaks of the engine coolant.
SLC252B
Thermostat
Valve opening temperature 80 - 84°C (176 - 183° F)
Full-open lift amount More than 10 mm/ 95°C (0.39 in/ 203°F)
Valve closing temperature 77°C (171°F) or higher
KBIA2502E

CO-22
< SERVICE INFORMATION >
SERVICE DATA AND SPECIFICATIONS (SDS)
SERVICE DATA AND SPECIFICATIONS (SDS)
Standard and LimitINFOID:0000000003531577
ENGINE COOLANT CAPACITY (APPROXIMATE)
Unit: (US gal, Imp gal)
THERMOSTAT
RADIATOR
Unit: kPa (kg/cm2, psi)
Engine coolant capacity with reservoir tank ("MAX" level) 14.4 (3 3/4, 3 1/8)
Valve opening temperature 80 - 84°C (176 - 183°F)
Maximum valve lift More than 10 mm/95°C (0.39 in/203°F)
Valve closing temperature 77°C (171°F) or higher
Reservoir cap relief pressure Standard 95 - 125 (0.97- 1.28, 14 - 18)
Leakage test pressure 137 (1.4, 20)

DI-6
< SERVICE INFORMATION >
COMBINATION METERS
POWER SUPPLY AND GROUND CIRCUIT
Power is supplied at all times
• through 10A fuse [No.19, located in the fuse block (J/B)]
• to combination meter terminal 8.
With the ignition switch in the ON or START position, power is supplied
• through 10A fuse [No.14, located in the fuse block (J/B)]
• to combination meter terminal 24.
Ground is supplied
• to combination meter terminal 17
• through body grounds M57, M61 and M79.
WATER TEMPERATURE GAUGE
The water temperature gauge indicates the engine coolant temperature.
ECM provides an engine coolant temperature signal to combination meter via CAN communication lines.
ENGINE OIL PRESSURE GAUGE
The engine oil pressure gauge indicates whether the engine oil pressure is low or normal.
The oil pressure gauge is controlled by the IPDM E/R (intelligent power distribution module engine room). Low
oil pressure causes oil pressure switch terminal 1 to provide ground to IPDM E/R terminal 42. The IPDM E/R
then signals the combination meter (unified meter control unit) via CAN communication lines and a low oil
pressure indication is displayed by the oil pressure gauge.
A/T OIL TEMPERATURE GAUGE
The A/T oil temperature gauge indicates the A/T fluid temperature.
TCM (transmission control module) provides an A/T flui d temperature signal to combination meter via CAN
communication lines.
VOLTAGE GAUGE
The voltage gauge indicates the battery/charging system voltage.
The voltage gauge is regulated by the unified meter control unit.
TA C H O M E T E R
The tachometer indicates engine speed in revolutions per minute (rpm).
ECM provides an engine speed signal to combination meter via CAN communication lines.
FUEL GAUGE
The fuel gauge indicates the approximate fuel level in the fuel tank.
The fuel gauge is regulated by the unified meter control unit and a variable resistor signal supplied
• to combination meter terminal 15.
• through fuel level sensor unit and fuel pump terminal 2
• through fuel level sensor unit and fuel pump terminal 5
• from combination meter terminal 16
SPEEDOMETER
ABS actuator and electric unit (contro l unit) provides a vehicle speed signal to the combination meter via CAN
communication lines.
ODO/TRIP METER
The vehicle speed signal and the memory signals from the meter memory circuit are processed by the combi-
nation meter and the mileage is displayed.
How to Change the Display
Refer to Owner's Manual for odo/tr ip meter operating instructions.
CAN COMMUNICATION SYSTEM DESCRIPTION
Refer to LAN-4.

COMBINATION METERSDI-15
< SERVICE INFORMATION >
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How to Proceed with Trouble DiagnosisINFOID:0000000003533487
1. Confirm the symptom or customer complaint.
2. Perform preliminary check. Refer to DI-15, "
Preliminary Check".
3. According to the symptom chart, repair or replace the cause of the symptom.
4. Does the meter operate normally? If so, go to 5. If not, go to 2.
5. Inspection End.
Preliminary CheckINFOID:0000000003533488
1.CHECK WARNING INDICATOR ILLUMINATION
1. Turn ignition switch ON.
2. Make sure warning indicators (such as malfunction indicator lamp and oil pressure low/coolant tempera- ture high warning indicator) illuminate.
Do warning indicators illuminate?
YES >> GO TO 2.
NO >> Check ignition power supply system of combination meter. Refer to DI-16, "
Power Supply and
Ground Circuit Inspection".
2.CHECK OPERATION OF SELF-DIAGNOSIS MODE (COMBINATION METER)
Next test requested A04XXXA/D port A/D value (non-
ratioed).0-255
Next test requested A05XXX A/D port A/D value (non-
ratioed).
0-255
Next test requested A06XXX A/D port A/D value (non-
ratioed).0-255
Next test requested A07XXX A/D port A/D value (non-
ratioed).0-255
Next test requested A08XXX A/D port A/D value (non-
ratioed).
0-255
Next test requested A09XXX A/D port A/D value (non-
ratioed).0-255
Next test requested A10XXX A/D port A/D value (non-
ratioed).0-255
Next test requested A11XXX A/D port A/D value (non-
ratioed).
0-255
Next test requested A12XXX A/D port A/D value (non-
ratioed).0-255
Next test requested A13XXX A/D port A/D value (non-
ratioed).0-255
Next test requested A14XXX A/D port A/D value (non-
ratioed).
0-255
Next test requested A15XXX A/D port A/D value (non-
ratioed).0-255
Next test requested PA0-XX Hex value representing
state of A/D ports 0-7.
Next test requested PA1-XX Hex value representing
state of A/D ports 0-7.
Next test requested Thr-XXX Decimal value of ther-
mistor A/D reading.0-255
Next test requested rXXXX, FAIL Return to beginning of self-di-
agnosis.
Event Odometer Display Description of Test/Data Notes:

EC-8
DTC Confirmation Procedure ................................567
Wiring Diagram ......................................................569
Diagnosis Procedure .............................................570
Component Inspection ...........................................572
Removal and Installation .......................................573
DTC P2135 TP SENSOR .................................574
Component Description .........................................574
CONSULT-II Reference Value in Data Monitor
Mode ......................................................................
574
On Board Diagnosis Logic .....................................574
DTC Confirmation Procedure ................................574
Wiring Diagram ......................................................576
Diagnosis Procedure .............................................577
Component Inspection ...........................................579
Removal and Installation .......................................580
DTC P2138 APP SENSOR ..............................581
Component Description .........................................581
CONSULT-II Reference Value in Data Monitor
Mode ......................................................................
581
On Board Diagnosis Logic .....................................581
DTC Confirmation Procedure ................................582
Wiring Diagram ......................................................583
Diagnosis Procedure .............................................584
Component Inspection ...........................................587
Removal and Installation .......................................587
DTC P2A00, P2A03 A/F SENSOR 1 ...............588
Component Description .........................................588
CONSULT-II Reference Value in Data Monitor
Mode ......................................................................
588
On Board Diagnosis Logic .....................................588
DTC Confirmation Procedure ................................588
Wiring Diagram ......................................................590
Diagnosis Procedure .............................................593
Removal and Installation .......................................596
ASCD BRAKE SWITCH ..................................597
Component Description .........................................597
CONSULT-II Reference Value in Data Monitor
Mode ......................................................................
597
Wiring Diagram ......................................................598
Diagnosis Procedure .............................................599
Component Inspection ...........................................602
ASCD INDICATOR ..........................................603
Component Description .........................................603
CONSULT-II Reference Value in Data Monitor
Mode ......................................................................
603
Wiring Diagram ......................................................604
Diagnosis Procedure .............................................604
ELECTRICAL LOAD SIGNAL .........................606
Description .............................................................606
CONSULT-II Reference Value in Data Monitor
Mode ......................................................................
606
Diagnosis Procedure .............................................606
FUEL INJECTOR ..............................................608
Component Description ........................................608
CONSULT-II Reference Value in Data Monitor
Mode .....................................................................
608
Wiring Diagram .....................................................609
Diagnosis Procedure .............................................610
Component Inspection ..........................................612
Removal and Installation .......................................612
FUEL PUMP .....................................................613
Description ............................................................613
CONSULT-II Reference Value in Data Monitor
Mode .....................................................................
613
Wiring Diagram .....................................................614
Diagnosis Procedure .............................................615
Component Inspection ..........................................617
Removal and Installation .......................................618
ICC BRAKE SWITCH .......................................619
Component Description ........................................619
CONSULT-II Reference Value in Data Monitor
Mode .....................................................................
619
Wiring Diagram .....................................................620
Diagnosis Procedure .............................................621
Component Inspection ..........................................624
IGNITION SIGNAL ............................................626
Component Description ........................................626
Wiring Diagram .....................................................627
Diagnosis Procedure .............................................632
Component Inspection ..........................................635
Removal and Installation .......................................637
REFRIGERANT PRESSURE SENSOR ...........638
Component Description ........................................638
Wiring Diagram .....................................................639
Diagnosis Procedure .............................................640
Removal and Installation .......................................642
MIL AND DATA LINK CONNECTOR ...............643
Wiring Diagram .....................................................643
SERVICE DATA AND SPECIFICATIONS
(SDS) ................................................................
645
Fuel Pressure ........................................................645
Idle Speed and Ignition Timing .............................645
Calculated Load Value ..........................................645
Mass Air Flow Sensor ...........................................645
Intake Air Temperature Sensor .............................645
Engine Coolant Temperature Sensor ...................645
A/F Sensor 1 Heater .............................................645
Heated Oxygen sensor 2 Heater ..........................645
Crankshaft Position Sensor (POS) .......................646
Camshaft Position Sensor (PHASE) .....................646
Throttle Control Motor ...........................................646
Fuel Injector ..........................................................646
Fuel Pump .............................................................646

EC-22
< SERVICE INFORMATION >
PREPARATION
Commercial Service Tool
INFOID:0000000003531584
(J-45488)
Quick connector re-
leaseRemove fuel tube quick connectors in engine
room.
(J-23688)
Engine coolant refrac-
tometerChecking concentration of ethylene glycol in en-
gine coolant Tool number
(Kent-Moore No.)
Tool nameDescription
PBIC0198E
WBIA0539E
Tool name
(Kent-Moore No.)Description
Leak detector
i.e.: (J-41416)Locating the EVAP leak
EVAP service port
adapter
i.e.: (J-41413-OBD)Applying positive pressure through EVAP service
port
Fuel filler cap adapter
i.e.: (MLR-8382)Checking fuel tank vacuum relief valve opening
pressure
Socket wrench Removing and installing engine coolant tempera-
ture sensor
S-NT703
S-NT704
S-NT815
S-NT705

ENGINE CONTROL SYSTEM
EC-25
< SERVICE INFORMATION >
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*1: This sensor is not used to control the engine system. This is used only for the on board diagnosis.
*2: This signal is sent to the ECM through CAN communication line.
*3: ECM determines the start signal status by the signals of engine speed and battery voltage.
SYSTEM DESCRIPTION
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). The amount of fuel injected is a program value in the
ECM memory. The program value is preset by engine operating conditions. These conditions are determined
by input signals (for engine speed and intake air) from both the crankshaft position sensor and the mass air
flow sensor.
VARIOUS FUEL INJECTION INCREASE/DECREASE COMPENSATION
In addition, the amount of fuel injected is compensated 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 is changed from N to D
• High-load, high-speed operation

• During deceleration
• During high engine speed operation
MIXTURE RATIO FEEDBACK CONTROL (CLOSED LOOP CONTROL)
Sensor Input signal to ECM ECM function Actuator
Crankshaft position sensor (POS)
Engine speed*
3
Piston position
Fuel injection
& mixture ratio
controlFuel injector Camshaft position sensor (PHASE)
Mass air flow sensor Amount of intake air
Engine coolant temperature sensor Engine coolant temperature
Air fuel ratio (A/F) sensor 1 Density of oxygen in exhaust gas
Throttle position sensor Throttle position
Accelerator pedal position sensor Accelerator pedal position
Park/neutral position (PNP) switch Gear position
Knock sensor Engine knocking condition
Battery
Battery voltage*
3
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*
2
Air conditioner switch
Air conditioner operation*2
Wheel sensor
Vehicle speed*2
PBIB3020E

EC-26
< SERVICE INFORMATION >
ENGINE CONTROL SYSTEM
The mixture ratio feedback system provides the best air-fuel mixture ratio for driveability and emission control.
The three way catalyst (manifold) can then better reduce CO, HC and NOx emissions. This system uses air
fuel ratio (A/F) sensor 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 air
fuel ratio (A/F) sensor 1, refer to EC-225
. 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 three way catalyst (manifold). Even if the switching
characteristics of air fuel ratio (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 the mixture ratio signal transmitted from A/F sensor 1.
This feedback signal is then sent to the ECM. The ECM controls the basic mixture ratio as close to the theoret-
ical mixture ratio as possible. However, the basic mixture ratio is not necessarily controlled as originally
designed. Both manufacturing differences (i.e., mass air flow sensor hot wire) and characteristic changes dur-
ing operation (i.e., 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 compared 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 compensation 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 carried out long-term to compensate for continual deviation
of the short term fuel trim from the central value. Such deviation will occur due to individual engine differences,
wear over time and changes in the usage environment.
FUEL INJECTION TIMING
Two types of systems are used.
Sequential Multiport Fuel Injection System
Fuel is injected into each cylinder during each engine cycle according to the firing order. This system is used
when the engine is running.
Simultaneous Multiport Fuel Injection System
Fuel is injected simultaneously into all eight cylinders twice each engine cycle. In other words, pulse signals of
the same width are simultaneously transmitted from the ECM.
The eight fuel injectors will then receive the signals two times for each engine cycle.
PBIB0122E

ENGINE CONTROL SYSTEM
EC-27
< SERVICE INFORMATION >
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This system is used when the engine is being started and/or if the fail-safe system (CPU) is operating.
FUEL SHUT-OFF
Fuel to each cylinder is cut off during deceleration, operation of the engine at excessively high speeds or oper-
ation of the vehicle at excessively high speed.
Electronic Ignition (EI) SystemINFOID:0000000003531587
INPUT/OUTPUT SIGNAL CHART
*1: This signal is sent to the ECM through CAN communication line.
*2: ECM determines the start signal status by the signals of engine speed and battery voltage.
SYSTEM DESCRIPTION
Firing 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 revised 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.
Fuel Cut Control (at No Load and High Engine Speed)INFOID:0000000003531588
INPUT/OUTPUT SIGNAL CHART
*: This signal is sent to the ECM through CAN communication line.Sensor Input signal to ECM ECM function Actuator
Crankshaft position sensor (POS)
Engine speed*
2
Piston position
Ignition timing
controlPower transistor Camshaft position sensor (PHASE)
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
Knock sensor Engine knocking
Park/neutral position (PNP) switch Gear position
Battery
Battery voltage*
2
Wheel sensor
Vehicle speed*1
Sensor Input signal to ECM ECM function Actuator
Park/neutral position (PNP) switch Neutral position
Fuel cut control Fuel injector Accelerator pedal position sensor Accelerator pedal position
Engine coolant temperature sensor Engine coolant temperature
Crankshaft position sensor (POS)
Camshaft position sensor (PHASE)Engine speed
Wheel sensor Vehicle speed*