2008 INFINITI QX56 engine

P2A00, P2A03 A/F SENSOR 1EC-385
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P2A00, P2A03 A/F SENSOR 1
Component DescriptionINFOID:0000000001365856
The air fuel ratio (A/F) sensor 1 is a planar one-cell limit current sen-
sor. The sensor element of the A/F sensor 1 is composed an elec-
trode layer, which transports ions. It has a heater in the element.
The sensor is capable of precise m
easurement = 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.
The exhaust gas components diffuse through the diffusion layer at
the sensor cell. An electrode layer is applied voltage, and this current
relative oxygen density in lean. Also this current relative hydrocar-
bon density in rich.
Therefore, the A/F sensor 1 is able to indicate air fuel ratio by this
electrode layer of current. In addition, a heater is integrated in the
sensor to ensure the required operating temperature of about 800 °C
(1,472 °F).
On Board Diagnosis LogicINFOID:0000000001365858
To judge the malfunction, the A/F signal computed by ECM from the A/F sensor 1 signal is monitored not to be
shifted to LEAN side or RICH side.
DTC Confirmation ProcedureINFOID:0000000001365859
NOTE:
If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
TESTING CONDITION:
Before performing the following procedure, confirm that battery voltage is more than 11V at idle.
WITH CONSULT-IIl
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch OFF and wait at least 10 seconds.
3. Turn ignition switch ON and select “SELF-LEARNING CONT” in “WORK SUPPORT” mode with CON-
SULT-IIl.
4. Clear the self-learning coefficient by touching “CLEAR”.
5. Turn ignition switch OFF and wait at least 10 seconds.
6. Start engine and keep the engine speed between 3,500 and 4,000 rpm for 1 minute under no load.
7. Let engine idle for 1 minute.
PBIB3353E
PBIB3354E
DTC No. Trouble diagnosis name DTC detecting conditionPossible Cause
P2A00
2A00
(Bank 1) Air fuel ratio (A/F) sensor 1
circuit range/performance • The output voltage computed by ECM from the
A/F sensor 1 signal is shifted to the lean side for
a specified period.
• The A/F signal computed by ECM from the A/F
sensor 1 signal is shifted to the rich side for a
specified period. • A/F sensor 1
• A/F sensor 1 heater
• Fuel pressure
• Fuel injector
• Intake air leaks
P2A03
2A03
(Bank 2)
Revision: March 2010
2008 QX56

EC-386
< COMPONENT DIAGNOSIS >[VK56DE]
P2A00, P2A03 A/F SENSOR 1
8. Keep engine speed between 2,500 and 3,000 rpm for 20 minutes.
9. Check 1st trip DTC.
10. If 1st trip DTC is detected, go to
EC-386, "
Diagnosis Procedure".
WITH GST
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch OFF and wait at least 10 seconds.
3. Disconnect mass air flow sensor harness connector.
4. Start engine and let it idle for at least 5 seconds.
5. Stop engine and reconnect mass air flow sensor harness con-
nector.
6. Select Service $03 with GST and make sure that DTC P0102 is detected.
7. Select Service $04 with GST and erase the DTC P0102.
8. Start engine and keep the engine speed between 3,500 and 4,000 rpm for 1 minute under no load.
9. Let engine idle for 1 minute.
10. Keep engine speed between 2,500 and 3,000 rpm for 20 min- utes.
11. Select Service $07 with GST. If 1st trip DTC is detected, go to EC-386, "
Diagnosis Procedure".
Diagnosis ProcedureINFOID:0000000001365861
1.CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten two ground screws on the body. Refer to EC-86, "
Ground Inspection".
OK or NG
OK >> GO TO 2.
NG >> Repair or replace ground connections.
2.RETIGHTEN A/F SENSOR 1
1. Loosen and retighten the A/F sensor 1.
BBIA0368E
BBIA0354E
Tightening torque: 50 N-m (5.1 kg-m, 37 ft-lb)
BBIA0375E
Revision: March 2010 2008 QX56

P2A00, P2A03 A/F SENSOR 1EC-387
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>> GO TO 3.
3.CHECK FOR INTAKE AIR LEAK
1. Start engine and run it at idle.
2. Listen for an intake air leak after the mass air flow sensor.
OK or NG
OK >> GO TO 4.
NG >> Repair or replace.
4.CLEAR THE SELF-LEARNING DATA
With CONSULT-IIl
1. Start engine and warm it up to normal operating temperature.
2. Select “SELF-LEARNING CONT” in “W ORK SUPPORT” mode with CONSULT-IIl.
3. Clear the self-learning control coefficient by touching “CLEAR”.
4. Run engine for at least 10 minutes at idle speed. Is the 1st trip DTC P0171, P0172, P0174 or P0175 detected?
Is it difficult to start engine?
Without CONSULT-IIl
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch OFF.
3. Disconnect mass air flow sensor harness connector.
4. Restart engine and let it idle for at least 5 seconds.
5. Stop engine and reconnect mass air flow sensor harness con-
nector.
6. Make sure DTC P0102 is displayed.
7. Erase the DTC memory. Refer to EC-462, "
DTC Index".
8. Make sure DTC P0000 is displayed.
9. Run engine for at least 10 minutes at idle speed. Is the 1st trip DTC P0171, P0172, P0174 or P0175 detected?
Is it difficult to start engine?
Ye s o r N o
Yes >> Perform trouble diagnos is for DTC P0171, P0174 or
P0172, P0175. Refer to EC-176
or EC-182.
No >> GO TO 5.
5.CHECK HARNESS CONNECTOR
1. Turn ignition switch OFF.
2. Disconnect A/F sensor 1 harness connector.
3. Check harness connector for water.
OK or NG
OK >> GO TO 6.
NG >> Repair or replace harness connector.
6.CHECK A/F SENSOR 1 POWER SUPPLY CIRCUIT
BBIA0368E
Water should not exit.
BBIA0376E
Revision: March 2010 2008 QX56

P2A00, P2A03 A/F SENSOR 1EC-389
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10.CHECK INTERMITTENT INCIDENT
Perform GI-35, "
How to Check Terminal" and GI-38, "Intermittent Incident".
OK or NG
OK >> GO TO 11.
NG >> Repair or replace.
11 .REPLACE AIR FUEL RATIO (A/F) SENSOR 1
Replace malfunctioning air f uel ratio (A/F) sensor 1.
CAUTION:
• Discard any A/F sensor which has been dropped from a height of more than 0.5 m (19.7 in) onto a
hard surface such as a concrete floor; use a new one.
• Before installing new A/F senso r, clean exhaust system threads using Oxygen Sensor Thread
Cleaner tool J-43897-18 or J-43897-12 and approved anti-seize lubricant.
>> GO TO 12.
12.CONFIRM A/F ADJUSTMENT DATA
1. Turn ignition switch OFF and then ON.
2. Select “A/F ADJ-B1” and “” in “DATA MONITOR” mode with CONSULT-lll.
3. Make sure that “0.000” is displayed on CONSULT-lll screen.
OK or NG
OK >> INSPECTION END
NG >> GO TO 13.
13.CLEAR THE SELF-LEARNING DATA
With CONSULT-lll
1. Start engine and warm it up to normal operating temperature.
2. Select “SELF-LEARNING CONT” in “WORK SUPPORT” mode with CONSULT-lll.
3. Clear the self-learning control coefficient by touching “CLEAR”.
Without CONSULT-lll
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch OFF.
3. Disconnect mass air flow sensor harness connector.
4. Restart engine and let it idle for at least 5 seconds.
5. Stop engine and reconnect mass air flow sensor harness con- nector.
6. Make sure DTC P0102 is displayed.
7. Erase the DTC memory. Refer to EC-55, "
Malfunction Indicator
Lamp (MIL)".
8. Make sure DTC P0000 is displayed.
>> GO TO 14.
14.CONFIRM A/F ADJUSTMENT DATA
1. Turn ignition switch OFF and then ON.
2. Select “A/F ADJ-B1” and “A/F ADJ-B2” in “DATA MONITOR” mode with CONSULT-IIl.
3. Make sure that “0.000” is displayed on CONSULT-IIl screen.
>>INSPECTION END
BBIA0368E
Revision: March 2010 2008 QX56

FUEL INJECTOREC-399
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FUEL INJECTOR
Component DescriptionINFOID:0000000001365875
The fuel injector is a small, precise solenoid valve. When the ECM
supplies a ground to the fuel injector circuit, the coil in the fuel injec-
tor is energized. The energized coil pulls the ball valve back and
allows fuel to flow through the fuel injector into the intake manifold.
The amount of fuel injected depends upon the injection pulse dura-
tion. Pulse duration is the length of time the fuel injector remains
open. The ECM controls the injection pulse duration based on
engine fuel needs.
Diagnosis ProcedureINFOID:0000000001365878
1.INSPECTION START
Turn ignition switch to START.
Is any cylinder ignited?
Ye s o r N o
Yes >> GO TO 2.
No >> GO TO 3.
2.CHECK OVERALL FUNCTION
With CONSULT-IIl
1. Start engine.
2. Perform “POWER BALANCE” in “A CTIVE TEST” mode with CONSULT-IIl.
3. Make sure that each circuit produces a momentary engine speed drop.
Without CONSULT-IIl
1. Start engine.
2. Listen to each fuel injector operating sound.
Clicking noise should be heard.
OK or NG
OK >> INSPECTION END
NG >> GO TO 3.
3.CHECK FUEL INJECTOR POWER SUPPLY CIRCUIT
1. Turn ignition switch OFF.
SEF375Z
PBIB1986E
Revision: March 2010 2008 QX56

EC-402
< COMPONENT DIAGNOSIS >[VK56DE]
FUEL PUMP
FUEL PUMP
DescriptionINFOID:0000000001365881
SYSTEM DESCRIPTION
*: ECM determines the start signal status by the signals of engine speed and battery voltage.
The ECM activates the fuel pump for several seconds after the ignition switch is turned ON to improve engine
startability. If the ECM receives a engine speed signal
from the camshaft position sensor (PHASE), it knows
that the engine is rotating, and causes the pump to operate. If the engine speed signal is not received when
the ignition switch is ON, the engine stalls. The EC M stops pump operation and prevents battery discharging,
thereby improving safety. The ECM does not directly drive the fuel pump. It controls the ON/OFF fuel pump
relay, which in turn controls the fuel pump.
COMPONENT DESCRIPTION
A turbine type design fuel pump is used in the fuel tank.
Diagnosis ProcedureINFOID:0000000001365884
1.CHECK OVERALL FUNCTION
1. Turn ignition switch ON.
2. Pinch fuel feed hose with two fingers.
OK or NG
OK >> INSPECTION END
NG >> GO TO 2.
2.CHECK FUEL PUMP POWER SUPPLY CIRCUIT-I
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Turn ignition switch ON.
Sensor Input signal to ECMECM FunctionActuator
Crankshaft position sensor (POS)
Camshaft position sensor (PHASE) Engine speed*
Fuel pump control Fuel pump relay
Battery Battery voltage*
Condition Fuel pump operation
Ignition switch is turned to ON. Operates for 1 second.
Engine running and cranking Operates.
When engine is stopped Stops in 1.5 seconds.
Except as shown above Stops.
BBIA0402E
Fuel pressure pulsation should be felt on the fuel feed
hose for 1 second after igniti on switch is turned ON.
BBIA0357E
Revision: March 2010 2008 QX56

IGNITION SIGNALEC-411
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IGNITION SIGNAL
Component DescriptionINFOID:0000000001365892
IGNITION COIL & POWER TRANSISTOR
The ignition signal from the ECM is sent to and amplifi
ed by the power transistor. The power transistor turns
ON and OFF the ignition coil primary circuit. This ON/OFF operation induces the proper high voltage in the coil
secondary circuit.
Diagnosis ProcedureINFOID:0000000001365894
1.CHECK ENGINE START
Turn ignition switch OFF, and restart engine.
Is engine running?
Ye s o r N o
Yes (With CONSULT-IIl)>>GO TO 2.
Yes (Without CONSULT-lII)>>GO TO 3.
No >> GO TO 4.
2.CHECK OVERALL FUNCTION
With CONSULT-IIl
1. Perform “POWER BALANCE” in “A CTIVE TEST” mode with CONSULT-lII.
2. Make sure that each circuit produces a momentary engine speed drop.
OK or NG
OK >> INSPECTION END
NG >> GO TO 10.
3.CHECK OVERALL FUNCTION
Without CONSULT-IIl
1. Let engine idle.
2. Read the voltage signal between ECM terminals 46, 60, 61, 62, 65, 79, 80, 81 and ground with an oscilloscope.
3. Verify that the oscilloscope screen shows the signal wave as shown below.
NOTE:
The pulse cycle changes depending on rpm at idle.
OK or NG
1. Ignition coils (with power transistor) (bank 2) 2. Ignition coils (with power transistor)
(bank 1)
BBIA0777E
PBIB2094E
PBIB0044E
Revision: March 2010 2008 QX56

IGNITION SIGNALEC-415
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7. Remove fuel pump fuse in IPDM E/R to release fuel pressure.
NOTE:
Do not use CONSULT-IIl to release fuel pressure, or fuel pres-
sure applies again during the following procedure.
8. Start engine.
9. After engine stalls, crank it two or three times to release all fuel pressure.
10. Turn ignition switch OFF.
11. Remove all ignition coil harness connectors to avoid the electri- cal discharge from the ignition coils.
12. Remove ignition coil and spark plug of the cylinder to be checked.
13. Crank engine for 5 seconds or more to remove combustion gas in the cylinder.
14. Connect spark plug and harness connector to ignition coil.
15. Fix ignition coil using a rope etc. with gap of 13 - 17 mm between the edge of the spark plug and grounded metal portion
as shown in the figure.
16. Crank engine for about 3 seconds, and check whether spark is generated between the spark plug and the grounded metal por-
tion.
CAUTION:
• Do not approach to the spark plug and the ignition coil
within 50cm. Be careful not to get an electrical shock
while checking, because the el ectrical discharge voltage
becomes 20kV or more.
• It might cause to damage the ignition coil if the gap of more than 17 mm is taken.
NOTE:
When the gap is less than 13 mm, the spark might be generated even if the coil is malfunctioning.
17. If NG, replace ignition coil with power transistor.
CONDENSER-1
1. Turn ignition switch OFF.
2. Disconnect condenser-1 harness connector.
3. Check resistance between condenser-1 terminals 1 and 2. Spark should be generated.
BBIA0380E
PBIB2325E
Resistance
Above 1 MΩ at 25 °C (77 °F)
PBIB0794E
Revision: March 2010 2008 QX56