2011 INFINITI QX56 fuel line 2011

EC-12
< PRECAUTION >[VK56VD]
PRECAUTIONS

When measuring ECM signals with a circuit tester, never allow
the two tester probes to contact.
Accidental contact of probes will cause a short circuit and
damage the ECM power transistor.
 B1 indicates bank 1, B2 indicat es bank 2 as shown in the fig-
ure.
 Never operate fuel pump when there is no fuel in lines.
 Tighten fuel hose clamps to the specified torque.
 Never depress accelerator pedal when starting.
 Immediately after starting, never rev up engine unnecessarily.
 Never rev up engine just prior to shutdown.
SEF348N
PBIB1144E
SEF709Y
Revision: 2010 May2011 QX56

EC-22
< SYSTEM DESCRIPTION >[VK56VD]
COMPONENT PARTS
Battery Current Sensor (With Battery Temperature Sensor)
INFOID:0000000006217663
OUTLINE
The power generation voltage variable control enables fuel con-
sumption to be decreased by reducing the engine load which is
caused by the power generation of the generator.
Based on sensor signals, ECM judges whether or not the power
generation voltage variable control is performed. When performing
the power generation voltage variable control, ECM calculates the
target power generation voltage based on the sensor signal. And
ECM sends the calculated value as the power generation command
value to IPDM E/R. For the details of the power generation voltage
variable control, refer to CHG-7, "
POWER GENERATION VOLTAGE
VARIABLE CONTROL SYSTEM : System Description".
CAUTION:
Never connect the electrical component or the groun d wire directly to the battery terminal. The con-
nection causes the malfunction of th e power generation voltage variable control, and then the battery
discharge may occur.
BATTERY CURRENT SENSOR
The battery current sensor is installed to the battery cable at the negative terminal. The sensor measures the
charging/discharging current of the battery.
BATTERY TEMPERATURE SENSOR
Battery temperature sensor is int egrated in battery current sensor.
The sensor measures ambient temperature around the battery.
The electrical resistance of the t hermistor decreases as temperature
increases.

*: These data are reference values and are measured between ECM terminals.
Camshaft Position SensorINFOID:0000000006217664
The camshaft position (CMP) sensor senses the protrusion of the
signal plate installed to the camshaft (INT) front end to identify a par-
ticular cylinder. The camshaft position sensor senses the piston posi-
tion.
The sensor consists of a permanent magnet and Hall IC.
When engine is running, the high and low parts of the teeth cause
the gap with the sensor to change.
The changing gap causes the magnetic field near the sensor to
change.
Due to the changing magnetic field, the voltage from the sensor
changes.
When the crankshaft position sens or system becomes inoperative,
the camshaft position sensor provides various controls of engine parts instead, utilizing timing of cylinder iden-
tification signals.
JPBIA3262ZZ
Temperature [ °C ( °F)] Voltage* (V) Resistance (k Ω)
25 (77) 3.333 1.9 - 2.1
90 (194) 0.969 0.222 - 0.258
SEF012P
JMBIA0064ZZ
Revision: 2010 May2011 QX56

COMPONENT PARTSEC-23
< SYSTEM DESCRIPTION > [VK56VD]
C
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EC
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ECM receives the signals as shown in the figure.
Crankshaft Position SensorINFOID:0000000006217665
The crankshaft position (CKP) sensor senses the protrusion of the
signal plate installed to the drive plate to identify fluctuation of the
engine revolution.
The sensor consists of a permanent magnet and Hall IC.
When the engine is running, the high and low parts of the teeth
cause the gap with the sensor to change.
The changing gap causes the magnetic field near the sensor to
change.
Due to the changing magnetic fiel
d, the voltage from the sensor
changes.
The ECM receives the voltage signal and detects the fluctuation of
the engine revolution.
ECM receives the signals as shown in the figure.
ECMINFOID:0000000006217666
 ECM (Engine Control Module) controls the engine.
 The ECM consists of a microcomputer and connectors for trans- mitting/receiving signals and for supplying power. Furthermore, the
ECM is equipped with an injector dr iver unit and actuates the fuel
injector at a high voltage (approximately 70 V at the maximum).
 ECM is equipped with ECM temperature sensors. If ECM is over- heated, ECM controls output torque to prevent damage to itself.
 Battery voltage is supplied to the ECM even when the ignition
switch is turned OFF for the ECM memory function of the DTC
memory, the air-fuel ratio feedback compensation value memory,
the idle air volume learning value memory, etc.
Electric Throttle Control ActuatorINFOID:0000000006217667
OUTLINE
JMBIA1559GB
JMBIA0062ZZ
JMBIA1559GB
JMBIA0057ZZ
Revision: 2010 May2011 QX56

EC-26
< SYSTEM DESCRIPTION >[VK56VD]
COMPONENT PARTS
EVAP Control System Pressure Sensor
INFOID:0000000006256476
The EVAP control system pressure s ensor detects pressure in the
purge line. The sensor output voltage to the ECM increases as pres-
sure increases.
EVAP Canister Vent Control ValveINFOID:0000000006256477
The EVAP canister vent control valve is located on the EVAP canis-
ter and is used to seal the canister vent.
This solenoid valve responds to signals from the ECM. When the
ECM sends an ON signal, the coil in the solenoid valve is energized.
A plunger will then move to seal the canister vent. The ability to seal
the vent is necessary for the on board diagnosis of other evaporative
emission control system components.
This solenoid valve is used only for diagnosis, and usually remains
opened.
When the vent is closed, under normal purge conditions, the evapo-
rative emission control system is depressurized and allows “EVAP
Control System” diagnosis.
EVAP Canister Purge Volume Control Solenoid ValveINFOID:0000000006217671
The EVAP canister purge volume control solenoid valve is used to
control the flow rate of fuel vapor from the EVAP canister. The EVAP
canister purge volume control solenoid valve is moved by ON/OFF
pulses from the ECM. The longer the ON pulse, the greater the
amount of fuel vapor that will flow through the valve.
Fuel InjectorINFOID:0000000006217672
For the fuel injector, a high pressure fuel injector is used and this
enables a high-pressure fuel injection at a high voltage within a short
time. The ECM is equipped with an injector driver unit and actuates
the fuel injector at a high volt age (approximately 65 V at the maxi-
mum).
Fuel Level SensorINFOID:0000000006217673
The fuel level sensor is mounted in the fuel level sensor unit.
PBIB3370E
PBIB1263E
JMBIA0069ZZ
JSBIA0287ZZ
Revision: 2010 May2011 QX56

COMPONENT PARTSEC-27
< SYSTEM DESCRIPTION > [VK56VD]
C
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EC
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The sensor detects a fuel level in the fuel tank and tr
ansmits a signal to the combination meter. The combina-
tion meter sends the fuel level sensor signal to the ECM via the CAN communication line.
It consists of two parts, one is mechanical float and the ot her is variable resistor. Fuel level sensor output volt-
age changes depending on the movement of the fuel mechanical float.
Fuel Pump Control ModuleINFOID:0000000006217674
The fuel pump control module (FPCM) controls the discharging vol-
ume of the fuel pump by transmitt ing the FPCM control signals (Low/
Mid/High) depending on driving conditions.
Fuel Rail Pressure SensorINFOID:0000000006217675
The fuel rail pressure (FRP) sensor is placed to the fuel rail and
measures fuel pressure in the fuel rail. The sensor transmits voltage
signal to the ECM. As the pressure increases, the voltage rises. The
ECM controls the fuel pressure in the fuel rail by operating high pres-
sure fuel pump. The ECM uses the signal from fuel rail pressure sen-
sor as a feedback signal.
Fuel Tank Temperature SensorINFOID:0000000006217676
The fuel tank temperature sensor is used to detect the fuel tempera-
ture inside the fuel tank. The sensor modifies a voltage signal from
the ECM. The modified signal returns to the ECM as the fuel temper-
ature 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.
Heated Oxygen Sensor 2INFOID:0000000006217677
DESCRIPTION
NNBIB0006ZZ
JSBIA0291ZZ
Fuel temperature [ °C ( °F)] Voltage* (V) Resistance (k Ω)
20 (68) 3.5 2.3 - 2.7
50 (122) 2.2 0.79 - 0.90
SEF012P
Revision: 2010 May2011 QX56

EC-34
< SYSTEM DESCRIPTION >[VK56VD]
STRUCTURE AND OPERATION
On Board Refueling V apor Recovery (ORVR)
INFOID:0000000006217696
From the beginning of refueling, the air and vapor insi de the fuel tank go through refueling EVAP vapor cut
valve and EVAP/ORVR line to the EVAP canister. The vapor is absorbed by the EVAP canister and the air is
released to the atmosphere.
When the refueling has reached the full level of the fuel tank, the refueling EVAP vapor cut valve is closed and
refueling is stopped because of auto shut-off. The vapor which was absorbed by the EVAP canister is purged
during driving.
WARNING:
When conducting inspections below, be sure to observe the following:
 Put a “CAUTION: FLAMMABLE” sign in workshop.
 Never smoke while servicing fuel system. Keep open flames and sparks away from work area.
 Always furnish the workshop with a CO
2 fire extinguisher.
CAUTION:
 Before removing fuel line parts, carry out the following procedures:
- Put drained fuel in an explosion-pr oof container and put lid on securely.
- Release fuel pressure from fuel line. Refer to EC-153, "
Work Procedure".
- Disconnect battery ground cable.
 Always replace O-ring when the fuel gauge retainer is removed.
 Never kink or twist hose and tube when they are installed.
 Never tighten hose and clamps excessively to avoid damaging hoses.
 After installation, run engine an d check for fuel leaks at connections.
 Never attempt to top off the fuel tank after the fuel pump nozzle shuts off automatically.
Continued refueling may cause fu el overflow, resulting in fuel spray and possibly a fire.
PBIB1068E
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

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