2011 INFINITI QX56 fuel pressure

EC-46
< SYSTEM DESCRIPTION >[VK56VD]
SYSTEM
*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
The evaporative emission system is used to reduce hydr
ocarbons emitted into the atmosphere from the fuel
system. This reduction of hydrocarbons is accomplis hed by activated charcoals in the EVAP canister.
The fuel vapor in the sealed fuel tank is led into t he EVAP canister which contains activated carbon and the
vapor is stored there when the engine is not oper ating or when refueling to the fuel tank.
The vapor in the EVAP canister is purged by the air through the purge line to the intake manifold when the
engine is operating. EVAP canister purge volume contro l solenoid valve is controlled by ECM. When the
engine operates, the flow rate of vapor controlled by EVAP canister purge volume control solenoid valve is
proportionally regulated as the air flow increases.
EVAP canister purge volume control solenoid valve also shuts off the vapor purge line during decelerating and
idling.
AIR CONDITIONING CUT CONTROL
Sensor Input signal to ECM ECM function Actuator
Crankshaft position sensor
Camshaft position sensor  Engine speed*
1
 Piston position
EVAP canister
purge flow controlEVAP canister purge volume
control solenoid valve
Mass air flow sensor Amount of intake air
Engine coolant temperature sensor Engine coolant temperature
Battery
Battery voltage*
1
Throttle position sensor Throttle position
Accelerator pedal position sensor Accelerator pedal position
Air fuel ratio (A/F) sensor 1 Density of oxygen in exhaust gas
(Mixture ratio
feedback signal)
Fuel tank temperature sensor Fuel temperature in fuel tank
EVAP control system pressure sensor Pressure in purge line
Combination meter Vehicle speed*
2
PBIB1631E
Revision: 2010 May2011 QX56

EC-64
< SYSTEM DESCRIPTION >[VK56VD]
DIAGNOSIS SYSTEM (ECM)
*: This function is not necessary
in the usual service procedure.
SELF-DIAG RESULTS MODE
Self Diagnostic Item
Regarding items of DTC and 1st trip DTC, refer to EC-98, "DTC Index".
How to Read DTC and 1st Trip DTC
DTCs and 1st trip DTCs related to the malfunction are displayed in “Self-diag results”.
 When ECM detects a 1st trip DTC, “1t” is displayed for “TIME”.
 When ECM has detected a current DTC, “0” is displayed for “TIME”.
 If “TIME” is neither “0” nor “1t”, the DTC occurred in the past and ECM shows the number of times the vehi-
cle has been driven since the last detection of the DTC.
How to Erase DTC and 1st Trip DTC
NOTE:
 If the ignition switch stays ON after repair work, be su re to turn ignition switch OFF once. Wait at least 10
seconds and then turn it ON (engine stopped) again.
 If the DTC is not for A/T related items (see EC-98, "
DTC Index"), skip step 1.
1. Erase DTC in TCM. Refer to TM-60, "
Diagnosis Description".
2. Select “ENGINE” with CONSULT-III.
3. Select “SELF-DIAG RESULTS”.
4. Touch “ERASE”. (DTC in ECM will be erased.)
WORK ITEM CONDITION USAGE
IDLE AIR VOL LEARN  THE IDLE AIR VOLUME THAT KEEPS THE ENGINE
WITHIN THE SPECIFIED RANGE IS MEMORIZED IN
ECM. When learning the idle air volume
EVAP SYSTEM CLOSE CLOSE THE EVAP CANISTER VENT CONTROL VALVE IN
ORDER TO MAKE EVAP SYSTEM CLOSE UNDER THE
FOLLOWING CONDITIONS.
 IGN SW ON
 ENGINE NOT RUNNING
 AMBIENT TEMPERATURE IS ABOVE 0
°C (32 °F).
 NO VACUUM AND NO HIGH PRESSURE IN EVAP SYS-
TEM
 FUEL TANK TEMP. IS MORE THAN 0 °C (32 °F).
 WITHIN 10 MINUTES AFTER STARTING “EVAP SYS-
TEM CLOSE”
 WHEN TRYING TO EXECUTE “EVAP SYSTEM CLOSE” UNDER THE CONDITION EXCEPT ABOVE, CONSULT-
III WILL DISCONTINUE IT AND DISPLAY APPROPRI-
ATE INSTRUCTION.
NOTE:
WHEN STARTING ENGINE, CONSULT-III MAY DIS-
PLAY “BATTERY VOLTAGE IS LOW. CHARGE BAT-
TERY”, EVEN WHEN USING A CHARGED BATTERY. When detecting EVAP vapor leak
in the EVAP system
FUEL PRESSURE RELEASE  FUEL PUMP WILL STOP BY TOUCHING “START” DUR-
ING IDLING.
CRANK A FEW TIMES AFTER ENGINE STALLS. When releasing fuel pressure from
fuel line
SELF-LEARNING CONT  THE COEFFICIENT OF SELF-LEARNING CONTROL
MIXTURE RATIO RETURNS TO THE ORIGINAL COEF-
FICIENT. When clearing mixture ratio self-
learning value
TARGET IDLE RPM ADJ*  IDLE CONDITION When setting target idle speed
VIN REGISTRATION  IN THIS MODE, VIN IS REGISTERED IN ECM. When registering VIN in ECM
TARGET IGN TIM ADJ*  IDLE CONDITION When adjusting target ignition tim-
ing
CLSD THL POS LEARN  IGNITION ON AND ENGINE STOPPED. When learning the throttle valve
closed position
VVEL POS SEN ADJ PREP  USE THIS ITEM ONLY WHEN REPLACING VVEL ACTU-
ATOR SUB ASSEMBLY.
 IGNITION ON AND ENGINE STOPPED. When adjusting VVEL control
shaft position sensor
Revision: 2010 May2011 QX56

EC-66
< SYSTEM DESCRIPTION >[VK56VD]
DIAGNOSIS SYSTEM (ECM)
A/F ALPHA-B1
% The mean value of the air-fuel ratio feedback cor-
rection factor per cycle is indicated.  When the engine is stopped,
a certain value is indicated.
 This data also includes the data for the air-fuel ratio
learning control.
 When engine is running, specification range is indicat-
ed in “SPEC”.
A/F ALPHA-B2
COOLAN TEMP/S
°C or °F  The engine coolant temperature (determined by
the signal voltage of the engine coolant tempera-
ture sensor) is displayed.  When the engine coolant
temperature sensor is open
or short-circuited, ECM en-
ters fail-safe mode. The en-
gine coolant temperature
determined by the ECM is
displayed.
A/F SEN1 (B1) V The A/F signal computed from the input signal of
the air fuel ratio (A/F) sensor 1 is displayed.
A/F SEN1 (B2)
HO2S2 (B1)
V The signal voltage of the heated oxygen sensor 2
is displayed.
HO2S2 (B2)
HO2S2 MNTR (B1)
RICH/LEAN Display of heated oxygen sensor 2 signal:
RICH: means the amount of oxygen after three
way catalyst is relatively small.
LEAN: means the amount of oxygen after three
way catalyst is relatively large.  When the engine is stopped,
a certain value is indicated.
HO2S2 MNTR (B2)
VHCL SPEED SE km/h or mph  The vehicle speed computed from the vehicle
speed signal sent from combination meter is dis-
played.
BATTERY VOLT V  The power supply voltage of ECM is displayed.
ACCEL SEN 1
V The accelerator pedal position sensor signal volt-
age is displayed.  ACCEL SEN 2 signal is con-
verted by ECM internally.
Thus, they differs from ECM
terminal voltage signal.
ACCEL SEN 2
TP SEN 1-B1
V The throttle position sensor signal voltage is dis-
played.  TP SEN 2-B1 signal is con-
verted by ECM internally.
Thus, they differs from ECM
terminal voltage signal.
TP SEN 2-B1
FUEL T/TMP SE
°C or °F  The fuel temperature (determined by the signal
voltage of the fuel tank temperature sensor) is dis-
played.
EVAP SYS PRES V  The signal voltage of EVAP control system pres-
sure sensor is displayed.
FUEL LEVEL SE V  The signal voltage of the fuel level sensor is dis-
played.
START SIGNAL ON/OFF  Indicates start signal status [ON/OFF] computed
by the ECM according to the signals of engine
speed and battery voltage.  After starting the engine,
[OFF] is displayed regard-
less of the starter signal.
CLSD THL POS ON/OFF  Indicates idle position [ON/OFF] computed by
ECM according to the accelerator pedal position
sensor signal.
AIR COND SIG ON/OFF  Indicates [ON/OFF] condition of the air conditioner
switch as determined by the air conditioner signal.
PW/ST SIGNAL ON/OFF  [ON/OFF] condition of the power steering system
(determined by the signal voltage of the power
steering pressure sensor signal) is indicated.
Monitored item Unit Description Remarks
Revision: 2010 May2011 QX56

EC-68
< SYSTEM DESCRIPTION >[VK56VD]
DIAGNOSIS SYSTEM (ECM)
VEHICLE SPEED km/h or mph The vehicle speed computed from the vehicle
speed signal sent from TCM is displayed.
IDL A/V LEARN YET/CMPLT  Displays the condition of Idle Air Volume Learning
YET: Idle air volume learning has not been per-
formed yet.
CMPLT: Idle air volume learning has already been
performed successfully.
TRVL AFTER MIL km or mile  Distance traveled while MIL is activated.
SNOW MODE SW ON/OFF  Indicates [ON/OFF] condition from the snow mode
switch signal.
ENG OIL TEMP °C or °F  The engine oil temperature (determined by the sig-
nal voltage of the engine oil temperature sensor) is
displayed.
MAIN SW ON/OFF  Indicates [ON/OFF] condition from MAIN switch
signal.
CANCEL SW ON/OFF  Indicates [ON/OFF] condition from CANCEL
switch signal.
RESUME/ACC SW ON/OFF  Indicates [ON/OFF] condition from RESUME/AC-
CELERATE switch signal.
SET SW ON/OFF  Indicates [ON/OFF] condition from SET/COAST
switch signal.
BRAKE SW1 ON/OFF  Indicates [ON/OFF] condition from ASCD brake
switch signal.
BRAKE SW2 ON/OFF  Indicates [ON/OFF] condition of stop lamp switch
signal.
DIST SW ON/OFF  Indicates [ON/OFF] condition from DISTANCE
switch signal.
CRUISE LAMP ON/OFF  Indicates [ON/OFF] condition of CRUISE indicator
determined by the ECM according to the input sig-
nals.
AC EVA TEMP °C or °F  Indicates A/C evaporator temperature sent from A/
C auto amp.
AC EVA TARGET °C or °F  Indicates target A/C evaporator temperature sent
from A/C auto amp.
FAN DUTY %  Indicates a command value for cooling fan. The
value is calculated by ECM based on input signals.
ALT DUTY %  Indicates the duty ratio of the power generation
command value. The ratio is calculated by ECM
based on the battery current sensor signal.
BAT CUR SEN mV  The signal voltage of battery current sensor is dis-
played.
A/F ADJ-B1
— Indicates the correction of a factor stored in ECM.
The factor is calculated from the difference be-
tween the target air-fuel ratio stored in ECM and
the air-fuel ratio calculated from A/F sensor 1 sig-
nal.
A/F ADJ-B2
P/N POSI SW ON/OFF
 Indicates [ON/OFF] condition from the park/neutral
position (PNP) signal.
INT/A TEMP SE °C or °F  The intake air temperature (determined by the sig-
nal voltage of the intake air temperature sensor) is
indicated.
AC PRESS SEN V  The signal voltage from the refrigerant pressure
sensor is displayed.
FUEL PRES SEN MPa  Indicates the fuel rail pressure computed by ECM
according to the input signals
Monitored item Unit Description Remarks
Revision: 2010 May2011 QX56

DIAGNOSIS SYSTEM (ECM)EC-69
< SYSTEM DESCRIPTION > [VK56VD]
C
D
E
F
G H
I
J
K L
M A
EC
NP
O
FUEL INJ B1 msec
 ECM-calculated injection pulse width of the fuel in-
jector on the Bank 1 side.
FUEL INJ B2 msec  ECM-calculated injection pulse width of the fuel in-
jector on the Bank 2 side.
INT/V TIM (B1) °CA  Indicates [ °CA] of intake camshaft advance angle.
INT/V TIM (B2)
MAP SENSOR V  The signal voltage from the manifold absolute
pressure (MAP) sensor is displayed.
EVAP LEAK DIAG YET/CMPLT  Indicates the condition of EVAP leak diagnosis.
YET: EVAP leak diagnosis has not been performed
yet.
CMPLT: EVAP leak diagnosis has been performed
successfully.
EVAP DIAG READY ON/OFF  Indicates the ready condition of EVAP leak diagno-
sis.
ON: Diagnosis has been ready condition.
OFF: Diagnosis has not been ready condition.
VVEL LEARN YET/DONE  Display the conditi
on of VVEL learning
YET: VVEL learning has not been performed yet.
DONE: VVEL learning has already been per-
formed successfully.
VVEL SEN LEARN-B1 V  Indicates the VVEL learning value.
VVEL SEN LEARN-B2
VVEL POSITION SEN-B1 V The VVEL control shaft position sensor signal volt-
age is displayed.
VVEL POSITION SEN-B2
VVEL TIM-B1
deg  Indicates [deg] of VVEL control shaft angle.
VVEL TIM-B2
FPCM HI/MID/LOW/
OFF  The control condition of the fuel pump control mod-
ule (FPCM) (determined by ECM according to the
input signals) is indicated.
BAT TEMP SEN V  The signal voltage from the battery temperature
sensor is displayed.
COOLING FAN SPD rpm  Displays a cooling fan speed from a signal of elec-
trically-controlled cooling fan coupling.
THRTL STK CNT B1* — —
HO2 S2 DIAG2(B1)* INCMP/CM-
PLT  Indicates DTC P0139 self-diagnosis (slow re-
sponse) condition.
INCMP: Self-diagnosis is incomplete.
CMPLT: Self-diagnosis is complete.
HO2 S2 DIAG2(B2)* INCMP/CM-
PLT  Indicates DTC P0159 self-diagnosis (slow re-
sponse) condition.
INCMP: Self-diagnosis is incomplete.
CMPLT: Self-diagnosis is complete.
FUEL INJ TIMG deg  Indicates the fuel injection timing computed by
ECM according to the input signals.
H/P FUEL PUMP DEG deg  Displays ECM-calculated fuel discharge position
of the high pressure fuel pump.
FUEL PRES SEN V mV  The signal voltage of FRP sensor is displayed.
L/FUEL PRES SEN MPa  Displays a pressure value calculated from a low
fuel pressure sensor voltage.
L/FUEL PRES SEN V mV  The signal voltage of low fuel pressure sensor is
displayed.
Monitored item Unit Description Remarks
Revision: 2010 May2011 QX56

ECM
EC-81
< ECU DIAGNOSIS INFORMATION > [VK56VD]
C
D
E
F
G H
I
J
K L
M A
EC
NP
O
23
(V) 45
(L/O) Low fuel pressure sensor Input [Engine is running]
 Warm-up condition
 Idle speed
2.4 - 3.6 V
[Engine is running]
 Warm-up condition
 Engine speed: 2,000 rpm 2.4 - 3.6 V
25
(LG) —Sensor ground
[Mass air flow sensor/ Intake air
temperature sensor] —— —
27
(P) 45
(L/O) Sensor power supply
(Power steering pressure sen-
sor/ Low fuel pressure sensor/
Electrically-controlled cooling
fan coupling)
— [Ignition switch: ON] 5 V
28
(SB) 40
(W/L) Sensor power supply
(Fuel rail pressure sensor/En-
gine oil pressure sensor)
— [Ignition switch: ON] 5 V
29
(W) 35
(—) Knock sensor (bank 1) Input [Engine is running]
 Idle speed
2.0 V*
1
31
(V/W) 40
(W/L) Fuel rail pressure sensor Input [Engine is running]
 Warm-up condition
 Idle speed
0.98 - 1.2 V
[Engine is running]
 Warm-up condition
 Revving engine from idle to 4,000 rpm quickly 1.1 - 2.9 V
32
(R) 40
(W/L) Engine coolant temperature
sensor
Input [Engine is running] 0 - 4.8 V
Output voltage varies with engine
coolant temperature.
33
(W) 35
(—) Knock sensor (bank 2) Input [Engine is running]
 Idle speed
2.0 V*
1
35
(—) —Sensor ground
(Knock sensor)
—— —
Te r m i n a l N o .
(Wire color) Description
ConditionVa l u e
(Approx.)
+ – Signal name Input/
Output
JPBIA3357ZZ
JPBIA3358ZZ
Revision: 2010 May2011 QX56

EC-82
< ECU DIAGNOSIS INFORMATION >[VK56VD]
ECM
37
(V) 175
(B) Cooling fan speed Input [Ignition switch: ON]
 Engine stopped
5 V
[Engine is running]
 Idle speed
 After warm-up condition BATTERY VOLTAGE
(11 - 14 V)
[Engine is running]
 Idle speed
 Before warm-up condition BATTERY VOLTAGE
(11 - 14 V)
39
(P/B) 45
(L/O) Power steering pressure sensor Input [Engine is running]
 Steering wheel: Being turned
0.5 - 4.5 V
[Engine is running]
 Steering wheel: Not being turned 0.4 - 0.8 V
40
(W/L) —Sensor ground
(Fuel rail pressure sensor/En-
gine coolant temperature sen-
sor/Engine oil temperature
sensor) —— —
42
(L/Y) 40
(W/L) Engine oil temperature sensor Input [Engine is running] 0 - 4.8 V
Output voltage varies with engine
oil temperature.
45
(L/O) —Sensor ground
(Power steering pressure sen-
sor/ Low fuel pressure sensor/
Electrically-controlled cooling
fan coupling) —— —
46
(SB) 175
(B) Fuel injector driver power supply Input [Ignition switch: ON]
BATTERY VOLTAGE
(11 - 14 V)
[Ignition switch: OFF] 1.5 V
47
(G) 175
(B) Heated oxygen sensor 2 heater
(bank 1)
Input[Engine is running]
 Engine speed: Below 3,600 rpm af-
ter 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 10 V
[Ignition switch: ON]
 Engine: Stopped
[Engine is running]
 Engine speed: Above 3,600 rpm BATTERY VOLTAGE
(11 - 14 V)
Te r m i n a l N o .
(Wire color) Description
ConditionVa l u e
(Approx.)
+ – Signal name Input/
Output
JPBIA3332ZZ
JPBIA3733ZZ
JMBIA0037GB
Revision: 2010 May2011 QX56

EC-86
< ECU DIAGNOSIS INFORMATION >[VK56VD]
ECM
78
(L/R) 175
(B) A/F sensor 1 (bank 2) Input [Engine is running]
 Warm-up condition
 Engine speed: 2,000 rpm2.2 - 2.8V
Output voltage varies with air fuel
ratio.
79
(B) 97
(W) Throttle position sensor 2 Input [Ignition switch: ON]
 Engine: Stopped
 Selector lever: D position
 Accelerator pedal: Fully released
Less than 4.75 V
[Ignition switch: ON]
 Engine: Stopped
 Selector lever: D position
 Accelerator pedal: Fully depressed More than 0.36 V
80
(L/W) 175
(B) A/F sensor 1 (bank 2) Input [Ignition switch: ON] 3.0 V
81
(G) 97
(W) Sensor power supply
[Throttle position sensor (bank
1)]
— [Ignition switch: ON] 5 V
83
(LG/ R) 99
(LG/ B) Sensor power supply
[Camshaft position sensor (bank
2)]
— [Ignition switch: ON] 5 V
85
(GR/
R) 70
(W/L) Sensor power supply
(Manifold absolute pressure
sensor)
— [Ignition switch: ON] 5 V
86
(R/ W) 98
(G/ W) Crankshaft position sensor Input [Engine is running]
 Warm-up condition
 Idle speed
NOTE:
The pulse cycle changes depending
on rpm at idle 4.0 - 5.0 V
[Engine is running]
 Engine speed: 2,000 rpm 4.0 - 5.0 V
87
(L/W) 100
(R) Heated oxygen sensor 2 (bank
2)
Input[Engine is running]
 Revving engine from idle to 3,000
rpm quickly after the following condi-
tions 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 0 - 1.0 V
88
(B) 175
(B) A/F sensor 1 (bank 1) Input [Engine is running]
 Warm-up condition
 Engine speed: 2,000 rpm2.2 - 2.8 V
Output voltage varies with air fuel
ratio.
90
(W) 175
(B)
A/F sensor 1 (bank 1) Input [Ignition switch: ON] 3.0 V
Te r m i n a l N o .
(Wire color) Description
ConditionVa l u e
(Approx.)
+ – Signal name Input/
Output
JMBIA0041GB
JMBIA0042GB
Revision: 2010 May2011 QX56