fuel pressure INFINITI QX56 2006 Factory Owner's Guide

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1 - 6: The numbers refer to the order of inspection.
(continued on next page)Vehicle speed signal circuit
2 3 33EC-442
Power steering pressure sensor circuit 23 3 EC-448
ECM 22333333333 EC-453,
EC-457
Park/Neutral position (PNP) switch circuit 3 3 3 33EC-465
Refrigerant pressure sensor circuit 233 4 EC-630
Electrical load signal circuit 3EC-596
Air conditioner circuit 223333333 3 2 AT C - 3 4
ABS actuator and electric unit (control unit)4EC-471
,
EC-472

or BRC-11
SYMPTOM
Refer-
ence page
HARD/NO START/RESTART (EXCP. HA)
ENGINE STALL
HESITATION/SURGING/FLAT SPOT
SPARK KNOCK/DETONATION
LACK OF POWER/POOR ACCELERATION
HIGH IDLE/LOW IDLE
ROUGH IDLE/HUNTING
IDLING VIBRATION
SLOW/NO RETURN TO IDLE
OVERHEATS/WATER TEMPERATURE HIGH
EXCESSIVE FUEL CONSUMPTION
EXCESSIVE OIL CONSUMPTION
BATTERY DEAD (UNDER CHARGE)
Warranty symptom code AA AB AC AD AE AF AG AH AJ AK AL AM HA

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ENGINE CONTROL COMPONENT PARTS/CONTROL SYSTEMS APPLICATION
ItemDIAGNOSTIC TEST MODE
WORK SUP-
PORT SELF-DIAGNOSTIC
RESULTS DATA
MONI- TOR DATA
MONI- TOR
(SPEC) ACTIVE
TEST DTC & SRT
CONFIRMATION
DTC*1 FREEZE
FRAME
DATA*2 SRT
STATUS DTC
WORK
SUP-
PORT
ENGINE CONTROL COMPONENT PARTS
INPUT
Crankshaft position sensor (POS) ××××
Camshaft position sensor (PHASE) ××××
Mass air flow sensor ×××
Engine coolant temperature sensor ×××××
Air fuel ratio (A/F) sensor 1 ×××× ×
Heated oxygen sensor 2 ×××× ×
Wheel sensor ××××
Accelerator pedal position sensor ×××
Throttle position sensor ××××
Fuel tank temperature sensor ××××
EVAP control system pressure
sensor ××
×
Intake air temperature sensor ××××
Knock sensor ×
Refrigerant pressure sensor ××
Closed throttle position switch
(accelerator pedal position sensor
signal) ××
Air conditioner switch ××
Park/neutral position (PNP) switch ×××
Stop lamp switch ×××
Power steering pressure sensor ×××
Battery voltage ××
Load signal ××
Fuel level sensor ×××
ICC steering switch ×××
ASCD steering switch ×××
ICC brake switch ×××
ASCD brake switch ×××

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5. Touch “ENGINE”.
If “ENGINE ” is not indicated, go to GI-40, "
CONSULT-II Data
Link Connector (DLC) Circuit" .
6. Perform each diagnostic test mode according to each service procedure.
For further information, see the CONSULT-II Operation Manual.
WORK SUPPORT MODE
Work Item
BCIA0030E
BCIA0031E
WORK ITEM CONDITION USAGE
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
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
SELF-LEARNING CONT

THE COEFFICIENT OF SELF-LEARNING CONTROL
MIXTURE RATIO RETURNS TO THE ORIGINAL COEF-
FICIENT. When clearing the coefficient of
self-learning control value
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-
II WILL DISCONTINUE IT AND DISPLAY APPROPRI-
ATE INSTRUCTION.
NOTE:
WHEN STARTING ENGINE, CONSULT-II MAY DISPLAY
“BATTERY VOLTAGE IS LOW. CHARGE BATTERY”,
EVEN IN USING CHARGED BATTERY. When detecting EVAP vapor leak
point of EVAP system
VIN REGISTRATION

IN THIS MODE, VIN IS REGISTERED IN ECM When registering VIN in ECM

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DATA MONITOR MODE
Monitored Item
×: Applicable
Monitored item [Unit] ECM
INPUT
SIGNALS MAIN
SIGNALS Description
Remarks
ENG SPEED [rpm] ××

Indicates the engine speed computed
from the signal of the crankshaft position
sensor (POS) and camshaft position
sensor (PHASE).
Accuracy becomes poor if engine
speed drops below the idle rpm.

If the signal is interrupted while the
engine is running, an abnormal value
may be indicated.
MAS A/F SE-B1 [V] ××

The signal voltage of the mass air flow
sensor is displayed.
When the engine is stopped, a certain
value is indicated.
B/FUEL SCHDL
[msec] ×

Base fuel schedule indicates the fuel
injection pulse width programmed into
ECM, prior to any learned on board cor-
rection.
A/F ALPHA-B1 [%] ×

The mean value of the air-fuel ratio feed-
back correction factor per cycle is indi-
cated.
When the engine is stopped, a certain
value is indicated.

This data also includes the data for the
air-fuel ratio learning control.
A/F ALPHA-B2 [%]
×
COOLAN TEMP/S
[ °C] or [°F] ××

The engine coolant temperature (deter-
mined by the signal voltage of the
engine coolant temperature sensor) is
displayed.
When the engine coolant temperature
sensor is open or short-circuited, ECM
enters fail-safe mode. The engine
coolant temperature determined by the
ECM is displayed.
A/F SEN1 (B1) [V] ××

The A/F signal computed from the input
signal of the A/F sensor 1 is displayed.
A/F SEN1 (B2) [V] ×
HO2S2 (B1) [V] ×

The signal voltage of the heated oxygen
sensor 2 is displayed.
HO2S2 (B2) [V] ×
HO2S2 MNTR (B1)
[RICH/LEAN] ×

Display of heated oxygen sensor 2 sig-
nal:
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)
[RICH/LEAN] ×
VHCL SPEED SE
[km/h] or [mph] ××

The vehicle speed computed from the
vehicle speed signal sent from combina-
tion meter is displayed.
BATTERY VOLT [V] ××

The power supply voltage of ECM is dis-
played.
ACCEL SEN 1 [V] ××

The accelerator pedal position sensor
signal voltage is displayed.
ACCEL SEN 2 signal is converted by
ECM internally. Thus, it differs from
ECM terminal voltage signal.
ACCEL SEN 2 [V]
×
THRTL SEN 1 [V] ××

The throttle position sensor signal volt-
age is displayed.
THRTL SEN 2 signal is converted by
ECM internally. Thus, it differs from
ECM terminal voltage signal.
THRTL SEN 2 [V]
×
FUEL T/TMP SE
[ °C] or [°F] ×

The fuel temperature (determined by the
signal voltage of the fuel tank tempera-
ture sensor) is displayed.
INT/A TEMP SE
[ °C] or [°F] ××

The intake air temperature (determined
by the signal voltage of the intake air
temperature sensor) is indicated.
EVAP SYS PRES
[V] ×

The signal voltage of EVAP control sys-
tem pressure sensor is displayed.

EC-120Revision: November 2009
TROUBLE DIAGNOSIS
2006 QX56
FUEL LEVEL SE
[V]×
The signal voltage of the fuel level sen-
sor is displayed.
START SIGNAL
[ON/OFF] ××

Indicates start signal status [ON/OFF]
computed by the ECM according to the
signals of engine speed and battery volt-
age.

After starting the engine, [OFF] is dis-
played regardless of the starter signal.
CLSD THL POS
[ON/OFF] ××

Indicates idle position [ON/OFF] com-
puted by ECM according to the acceler-
ator 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.
P/N POSI SW
[ON/OFF] ××

Indicates [ON/OFF] condition from the
park/neutral position (PNP) switch sig-
nal.
PW/ST SIGNAL
[ON/OFF] ××

[ON/OFF] condition of the power steer-
ing system (determined by the signal
voltage of the power steering pressure
sensor signal) is indicated.
LOAD SIGNAL
[ON/OFF] ××

Indicates [ON/OFF] condition from the
electrical load signal.
ON: Rear window defogger switch is ON
and/or lighting switch is in 2nd position.
OFF: Both rear window defogger switch
and lighting switch are OFF.
IGNITION SW
[ON/OFF] ×

Indicates [ON/OFF] condition from igni-
tion switch signal.
HEATER FAN SW
[ON/OFF] ×

Indicates [ON/OFF] condition from
heater fan switch signal.
BRAKE SW
[ON/OFF] ×

Indicates [ON/OFF] condition from the
stop lamp switch signal.
INJ PULSE-B1
[msec] ×

Indicates the actual fuel injection pulse
width compensated by ECM according
to the input signals.
When the engine is stopped, a certain
computed value is indicated.
INJ PULSE-B2
[msec]
IGN TIMING
[BTDC] ×

Indicates the ignition timing computed
by ECM according to the input signals.
When the engine is stopped, a certain
value is indicated.
CAL/LD VALUE [%]

“ Calculated load value ” indicates the
value of the current air flow divided by
peak air flow.
MASS AIRFLOW
[g ·m/s]

Indicates the mass air flow computed by
ECM according to the signal voltage of
the mass air flow sensor.
PURG VOL C/V [%]

Indicates the EVAP canister purge vol-
ume control solenoid valve control value
computed by the ECM according to the
input signals.

The opening becomes larger as the
value increases.
AIR COND RLY
[ON/OFF] ×

The air conditioner relay control condi-
tion (determined by ECM according to
the input signals) is indicated.
FUEL PUMP RLY
[ON/OFF] ×

Indicates the fuel pump relay control
condition determined by ECM according
to the input signals.
Monitored item
[Unit] ECM
INPUT
SIGNALS MAIN
SIGNALS Description Remarks

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Generic Scan Tool (GST) FunctionUBS00L0C
DESCRIPTION
Generic Scan Tool (OBDII scan tool) complying with SAE J1978 has
8 different functions explained below.
ISO9141 is used as the protocol.
The name GST or Generic Scan Tool is used in this service manual.
FUNCTION
SEF139P
Diagnostic test modeFunction
Service $01 READINESS TESTS This diagnostic service gains access to current emission-related data values, including
analog inputs and outputs, digital inputs and outputs, and system status information.
Service $02 (FREEZE DATA) This diagnostic service gains access to emission-related data value which were stored by
ECM during the freeze frame. For details, refer to
EC-53, "
FREEZE FRAME DATA AND
1ST TRIP FREEZE FRAME DATA" .
Service $03 DTCs This diagnostic service gains access to emission-related power train trouble codes which
were stored by ECM.
Service $04 CLEAR DIAG INFO This diagnostic service can clear all emission-related diagnostic information. This
includes:

Clear number of diagnostic trouble codes (Service $01)

Clear diagnostic trouble codes (Service $03)

Clear trouble code for freeze frame data (Service $01)

Clear freeze frame data (Service $02)

Reset status of system monitoring test (Service $01)

Clear on board monitoring test results (Service $06 and $07)
Service $06 (ON BOARD TESTS) This diagnostic service accesses the results of on board diagnostic monitoring tests of
specific components/systems that are not continuously monitored.
Service $07 (ON BOARD TESTS) This diagnostic service enables the off board test drive to obtain test results for emission-
related powertrain components/systems that are continuously monitored during normal
driving conditions.
Service $08 —This diagnostic service can close EVAP system in ignition switch ON position (Engine
stopped). When this diagnostic service is performed, the EVAP canister vent control
valve can be closed.
In the following conditions, this diagnostic service cannot function.

Low ambient temperature

Low battery voltage

Engine running

Ignition switch OFF

Low fuel temperature

Too much pressure is applied to EVAP system
Service $09 (CALIBRATION ID) This diagnostic service enables the off-board test device to request specific vehicle infor-
mation such as Vehicle Identification Number (VIN) and Calibration IDs.

EC-134Revision: November 2009
TROUBLE DIAGNOSIS - SPECIFICATION VALUE
2006 QX56
TROUBLE DIAGNOSIS - SPECIFICATION VALUEPFP:00031
DescriptionUBS00L0F
The specification (SP) value indicates the tolerance of the value that is displayed in “DATA MONITOR (SPEC)”
mode of CONSULT-II during normal operation of the Engine Control System. When the value in “DATA MONI-
TOR (SPEC) ” mode is within the SP value, the Engine Control System is confirmed OK. When the value in
“DATA MONITOR (SPEC) ” mode is NOT within the SP value, the Engine Control System may have one or
more malfunctions.
The SP value is used to detect malfunctions that may affect the Engine Control System, but will not light the
MIL.
The SP value will be displayed for the following three items:

B/FUEL SCHDL (The fuel injection pulse width programmed into ECM prior to any learned on board cor-
rection)

A/F ALPHA-B1/B2 (The mean value of air-fuel ratio feedback correction factor per cycle)

MAS A/F SE-B1 (The signal voltage of the mass air flow sensor)
Testing ConditionUBS00L0G

Vehicle driven distance: More than 5,000 km (3,107 miles)

Barometric pressure: 98.3 - 104.3 kPa (1.003 - 1.064 kg/cm2 , 14.25 - 15.12 psi)

Atmospheric temperature: 20 - 30 °C (68 - 86 °F)

Engine coolant temperature: 75 - 95 °C (167 - 203 °F)

Engine speed: Idle

Transmission: Warmed-up
–After the engine is warmed up to normal operating temperature, drive vehicle until “ATF TEMP SE 1” (A/T
fluid temperature sensor signal) indicates more than 60 °C (140 °F).

Electrical load: Not applied
–Rear window defogger switch, air conditioner switch, lighting switch are OFF. Steering wheel is straight
ahead.
Inspection ProcedureUBS00L0H
NOTE:
Perform “DATA MONITOR (SPEC) ” mode in maximum scale display.
1. Perform EC-71, "
Basic Inspection" .
2. Confirm that the testing conditions indicated above are met.
3. Select “B/FUEL SCHDL ”, “A/F ALPHA-B1 ”, “A/F ALPHA-B2 ”
and “MAS A/F SE-B1 ” in “DATA MONITOR (SPEC) ” mode with
CONSULT-II.
4. Make sure that monitor items are within the SP value.
5. If NG, go to EC-135, "
Diagnostic Procedure" .
SEF601Z

EC-138Revision: November 2009
TROUBLE DIAGNOSIS - SPECIFICATION VALUE
2006 QX56
5. CHANGE ENGINE OIL
1. Stop the engine.
2. Change engine oil. NOTE:
This symptom may occur when a large amount of gasoline is mixed with engine oil because of driving
conditions (such as when engine oil temperature does not rise enough since a journey distance is too
short during winter). The symptom will not be detected after changing engine oil or changing driving con-
dition.
>>INSPECTION END
6. CHECK FUEL PRESSURE
Check fuel pressure. (Refer to EC-82, "
FUEL PRESSURE CHECK" .)
OK or NG
OK >> GO TO 9.
NG (Fuel pressure is too high)>>Replace fuel pressure regulator, refer to EC-82, "
FUEL PRESSURE
CHECK" . GO TO 8.
NG (Fuel pressure is too low)>>GO TO 7.
7. DETECT MALFUNCTIONING PART
1. Check the following.
–Clogged and bent fuel hose and fuel tube
–Clogged fuel filter
–Fuel pump and its circuit (Refer to EC-604, "FUEL PUMP" .)
2. If NG, repair or replace the malfunctioning part. (Refer to EC-82, "
FUEL PRESSURE CHECK" .)
If OK, replace fuel pressure regulator.
>> GO TO 8.
8. CHECK “A/F ALPHA-B1”, “A/F ALPHA-B2”
1. Start engine.
2. Select “A/F ALPHA-B1 ”, “A/F ALPHA-B2 ” in “DATA MONITOR (SPEC) ” mode, and make sure that the
each indication is within the SP value.
OK or NG
OK >> INSPECTION END
NG >> GO TO 9.
9. PERFORM POWER BALANCE TEST
1. Perform “POWER BALANCE ” in “ACTIVE TEST” mode.
2. Make sure that the each cylinder produces a momentary engine speed drop.
OK or NG
OK >> GO TO 12.
NG >> GO TO 10.
PBIB0133E

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10. DETECT MALFUNCTIONING PART
1. Check the following.
–Ignition coil and its circuit (Refer to EC-618, "IGNITION SIGNAL" .)
–Fuel injector and its circuit (Refer to EC-598, "FUEL INJECTOR" .)
–Intake air leakage
–Low compression pressure (Refer to EM-63, "CHECKING COMPRESSION PRESSURE" .)
2. If NG, repair or replace the malfunctioning part. If OK, replace fuel injector. (It may be caused by leakage from fuel injector or clogging.)
>> GO TO 11.
11 . CHECK “A/F ALPHA-B1”, “A/F ALPHA-B2”
1. Start engine.
2. Select “A/F ALPHA-B1 ”, “A/F ALPHA-B2 ” in “DATA MONITOR (SPEC) ” mode, and make sure that the
each indication is within the SP value.
OK or NG
OK >> INSPECTION END
NG >> GO TO 12.
12. CHECK A/F SENSOR 1 FUNCTION
Perform all DTC Confirmation Procedure related with A/F sensor 1.

For DTC P0130, P0150, refer to EC-213, "DTC Confirmation Procedure" .

For DTC P0131, P0151, refer to EC-223, "DTC Confirmation Procedure" .

For DTC P0132, P0132, refer to EC-232, "DTC Confirmation Procedure" .

For DTC P0133, P0153, refer to EC-242, "DTC Confirmation Procedure" .

For DTC P2A00, P2A03, refer to EC-575, "DTC Confirmation Procedure" .
OK or NG
OK >> GO TO 15.
NG >> GO TO 13.
13. CHECK A/F SENSOR 1 CIRCUIT
Perform Diagnostic Procedure according to corresponding DTC.
>> GO TO 14.
14. CHECK “A/F ALPHA-B1”, “A/F ALPHA-B2”
1. Start engine.
2. Select “A/F ALPHA-B1 ”, “A/F ALPHA-B2 ” in “DATA MONITOR (SPEC) ” mode, and make sure that the
each indication is within the SP value.
OK or NG
OK >> INSPECTION END
NG >> GO TO 15.
15. DISCONNECT AND RECONNECT ECM HARNESS CONNECTOR
1. Stop the engine.
2. Disconnect ECM harness connector. Check pin terminal and connector for damage, and then reconnect it.
>> GO TO 16.

DTC P0133, P0153 A/F SENSOR 1EC-241
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DTC P0133, P0153 A/F SENSOR 1PFP:22693
Component DescriptionUBS00N6R
The air fuel ratio (A/F) sensor 1 is a planar dual-cell limit current sen-
sor. The sensor element of the A/F sensor 1 is the combination of a
Nernst concentration cell (sensor cell) with an oxygen-pump cell,
which transports ions. It has a heater in the element.
The sensor is capable of precise measurement = 1, but also in the
lean and rich range. Together with its control electronics, the sensor
outputs a clear, continuous signal throughout a wide range (0.7 <
< air).
The exhaust gas components diffuse through the diffusion gap at the
electrode of the oxygen pump and Nernst concentration cell, where
they are brought to thermodynamic balance.
An electronic circuit controls the pump current through the oxygen-
pump cell so that the composition of the exhaust gas in the diffusion
gap remains constant at = 1. Therefore, the A/F sensor 1 is able to
indicate air/fuel ratio by this pumping of current. In addition, a heater
is integrated in the sensor to ensure the required operating tempera-
ture of 700 - 800 °C (1,292 - 1,472 °F).
CONSULT-II Reference Value in Data Monitor ModeUBS00N6S
Specification data are reference values.
On Board Diagnosis LogicUBS00N6T
To judge the malfunction of A/F sensor 1, this diagnosis measures response time of the A/F signal computed
by ECM from the A/F sensor 1 signal. The time is compensated by engine operating (speed and load), fuel
feedback control constant, and the A/F sensor 1 temperature index. Judgment is based on whether the com-
pensated time (the A/F signal cycling time index) is inordinately long or not.
SEF579Z
SEF580Z
MONITOR ITEM CONDITIONSPECIFICATION
A/F SEN1 (B1)
A/F SEN1 (B2)

Engine: After warming up Maintaining engine speed at 2,000 rpm Fluctuates around 1.5 V
DTC No. Trouble diagnosis name DTC detecting conditionPossible Cause
P0133
0133
(Bank 1)
Air fuel ratio (A/F) sensor 1
circuit slow response

The response of the A/F signal computed by
ECM from A/F sensor 1 signal takes more than
the specified time.

Harness or connectors
(The A/F sensor 1 circuit is open or
shorted.)

A/F sensor 1

A/F sensor 1 heater

Fuel pressure

Fuel injector

Intake air leaks

Exhaust gas leaks

PCV

Mass air flow sensor
P0153
0153
(Bank 2)