2008 INFINITI QX56 low oil pressure

TRANSFER ASSEMBLYDLN-163
< DISASSEMBLY AND ASSEMBLY > [ATX14B]
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f. With the lower body down, tighten the two bolts shown.
g. Apply ATF to the new O-rings, and install them to each solenoid valve, switch and terminal body.
CAUTION:
Do not reuse O-rings.
h. Install the following to the control valve assembly: • Clutch pressure solenoid valve
• Clutch pressure switch
• 2-4WD shift solenoid valve
• Line pressure switch
• Transfer fluid temperature sensor
10. Apply ATF to the new lip seals, and install them to the center case.
CAUTION:
• Do not reuse lip seals.
• There are 2 kinds of lip seals (lip seal of large inner diam-eter: 5 pieces, lip seal of small inner diameter: 2 pieces).
Confirm their position for installation.
11. Install the control valve assembly to the center case, and tighten to the specified torque. Refer to DLN-140, "
Disassembly and
Assembly".
CAUTION:
• Do not reuse any part that has been dropped or damaged.
• Make sure valve is assembled in the proper direction.
• Do not use a magnet becau se residual magnetism stays
during assembly.
12. Install the connector assembly into the center case, and secure with a snap ring.
13. Apply ATF to the new O-rings, and install them on the oil strainer.
CAUTION:
Do not reuse O-rings.
14. Install the oil strainer to the control valve assembly.
WDIA0198E
SDIA2123E
SDIA2121E
SDIA2122E
SDIA2782E
Revision: March 2010 2008 QX56

EC-22
< FUNCTION DIAGNOSIS >[VK56DE]
ENGINE CONTROL SYSTEM
Engine Control Comp onent Parts Location
INFOID:0000000001351343
1. ECM 2. Battery current sensor 3. Power steering pressure sensor
4. Ignition coil (with power transistor) and spark plug (bank 2) 5. Refrigerant pressure sensor 6. Intake valve timing control position
sensor (bank 2)
7. Intake valve timing control solenoid valve (bank 2) 8. Engine coolant temperature sensor 9. Electric throttle control actuator
10. Intake valve timing control position sensor (bank 1) 11. Intake valve timing control solenoid
valve (bank 1) 12. Cooling fan motor
13. Camshaft position sensor (PHASE) 14. I gnition coil (with power transistor)
and spark plug (bank 1) 15. Mass air flow sensor (with intake air
temperature sensor)
16. A/F sensor 1 (bank 1) 17. EVAP service port 18. Fuel injector (bank 1)
19. Knock sensor (bank 1) 20. EVAP canister purge volume control
solenoid valve 21. Knock sensor (bank 2)
22. Fuel injector (bank 2) 23. A/F sensor 1 (bank 2) 24. IPDM E/R
BBIA0743E
Revision: March 2010 2008 QX56

EC-78
< COMPONENT DIAGNOSIS >[VK56DE]
TROUBLE DIAGNOSIS - SPECIFICATION VALUE
Check “A/F ALPHA-B1”, “A/F ALPHA-B2” for approximat
ely 1 minute because they may fluctuate. It is NG
if the indication is out of the SP value even a little.
OK or NG
OK >> GO TO 17.
NG (Less than the SP value)>>GO TO 2.
NG (More than the SP value)>>GO TO 3.
2.CHECK “B/FUEL SCHDL”
Select “B/FUEL SCHDL” in “SPEC” of “DATA MONITOR” mode, and make sure that the indication is within the
SP value.
OK or NG
OK >> GO TO 4.
NG (More than the SP value)>>GO TO 19.
3.CHECK “B/FUEL SCHDL”
Select “B/FUEL SCHDL” in “SPEC” of “DATA MONITOR” mode, and make sure that the indication is within the
SP value.
OK or NG
OK >> GO TO 6.
NG (More than the SP value)>>GO TO 6.
NG (Less than the SP value)>>GO TO 25.
4.CHECK “A/F ALPHA-B1”, “A/F ALPHA-B2”
1. Stop the engine.
2. Disconnect PCV hose, and then plug it.
3. Start engine.
4. Select “A/F ALPHA-B1”, “A/F AL PHA-B2” in “SPEC” of “DATA MONITOR” mode, and make sure that the
each indication is within the SP value.
OK or NG
OK >> GO TO 5.
NG >> GO TO 6.
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-494, "
Fuel Pressure Check" .)
OK or NG
OK >> GO TO 9.
NG (Fuel pressure is too high)>>Replace fuel pressure regulator, refer to EC-494, "
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-494, "
Fuel Pressure Check" .)
2. If NG, repair or replace the malfunctioning part. (Refer to EC-494, "
Fuel Pressure Check" .)
If OK, replace fuel pressure regulator.
Revision: March 2010 2008 QX56

TROUBLE DIAGNOSIS - SPECIFICATION VALUEEC-79
< COMPONENT DIAGNOSIS > [VK56DE]
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>> 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 “SPEC” of “DATA MONITOR” 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.
10.DETECT MALFUNCTIONING PART
1. Check the following.
- Ignition coil and its circuit (Refer to EC-411, "
Diagnosis Procedure" .)
- Fuel injector and its circuit (Refer to EC-399, "
Diagnosis Procedure" .)
- Intake air leakage
- Low compression pressure (Refer to EM-23, "
Checking Compression Pressure".)
2. If NG, repair or replace the malfunctioning part. If OK, replace fuel injector. (It may be caus ed 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 “SPEC” of “DATA MONITOR” 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-141, "
DTC Confirmation Procedure" .
• For DTC P0131, P0151, refer to EC-145, "
DTC Confirmation Procedure" .
• For DTC P0132, P0132, refer to EC-149, "
DTC Confirmation Procedure" .
• For DTC P0133, P0153, refer to EC-153, "
DTC Confirmation Procedure" .
• For DTC P2A00, P2A03, refer to EC-385, "
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 “SPEC” of “DATA MONITOR” mode, and make sure that the each indication is within the SP value.
OK or NG
Revision: March 2010 2008 QX56

P0011, P0021 IVT CONTROLEC-91
< COMPONENT DIAGNOSIS > [VK56DE]
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5. Check 1st trip DTC.
6. If 1st trip DTC is detected, go to
EC-91, "
Diagnosis Procedure".
With GST
Follow the procedure “With CONSULT-III” above.
PROCEDURE FOR MALFUNCTION B
With CONSULT-III
1. Turn ignition switch ON.
2. Select “DATA MONITOR” mode with CONSULT-III.
3. Maintain the following conditions for at least 10 consecutive seconds.
4. Check 1st trip DTC.
5. If 1st trip DTC is detected, go to EC-91, "
Diagnosis Procedure".
With GST
Follow the procedure “With CONSULT-III” above.
Diagnosis ProcedureINFOID:0000000001351373
1.CHECK OIL PRESSURE WARNING LAMP
1. Start engine.
2. Check oil pressure warning lamp and confirm it is not illumi- nated.
OK or NG
OK >> GO TO 2.
NG >> Go to LU-8, "
Inspection".
2.CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body.
ENG SPEED Idle
COOLAN TEMP/S More than 70 °C (158 °F)
Selector lever P or N position
ENG SPEED1,700 - 3,175 rpm (A constant rotation is maintained.)
COOLAN TEMP/S More than 70 °C (158 °F)
Selector lever 1st or 2nd position
Driving location uphill Driving vehicle uphill
(Increased engine load will help maintain the driving con-
ditions required for this test.)
PBIA8559J
Revision: March 2010
2008 QX56

P0075, P0081 IVT CONTROL SOLENOID VALVEEC-103
< COMPONENT DIAGNOSIS > [VK56DE]
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P0075, P0081 IVT CONTROL SOLENOID VALVE
Component DescriptionINFOID:0000000001351393
Intake valve timing control solenoid valve is activated by ON/OFF
pulse duty (ratio) signals from the ECM.
The intake valve timing control solenoid valve changes the oil
amount and direction of flow through intake valve timing control unit
or stops oil flow.
The longer pulse width advances valve angle.
The shorter pulse width retards valve angle.
When ON and OFF pulse widths become equal, the solenoid valve
stops oil pressure flow to fix the intake valve angle at the control
position.
On Board Diagnosis LogicINFOID:0000000001351395
DTC Confirmation ProcedureINFOID:0000000001351396
NOTE:
If DTC Confirmation Procedure has been previously conducted, alw
ays turn ignition switch OFF and
wait at least 10 seconds before conducting the next test.
WITH CONSULT-III
1. Start engine and let it idle for 5 seconds.
2. Check 1st trip DTC.
3. If 1st trip DTC is detected, go to EC-103, "
Diagnosis Procedure".
WITH GST
Following the procedure “WITH CONSULT-III” above.
Diagnosis ProcedureINFOID:0000000001351398
1.CHECK INTAKE VALVE TIMING CONTROL SO LENOID VALVE POWER SUPPLY CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect intake valve timing control solenoid valve harness connector.
PBIB1842E
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0075
0075
(Bank 1) Intake valve timing control
solenoid valve circuit An improper voltage is sent to the ECM
through intake valve timing control solenoid
valve. • Harness or connectors
(Intake valve timing control solenoid valve
circuit is open or shorted.)
• Intake valve timing control solenoid valve
P0081
0081
(Bank 2)
BBIA0771E
Revision: March 2010
2008 QX56

EC-200
< COMPONENT DIAGNOSIS >[VK56DE]
P0300, P0301, P0302, P
0303, P0304, P0305, P0306, P0307, P0308 MISFIRE
When disconnecting each fuel injector harness connector one at a time, is there any cylinder which does not
produce a momentary engine speed drop?
Ye s o r N o
Ye s > > G O T O 4 .
No >> GO TO 7.
4.CHECK FUEL INJECTOR
Does each fuel injector make an operating sound at idle?
Ye s o r N o
Yes >> GO TO 5.
No >> Check fuel injector(s) and circuit(s). Refer to EC-399,
"Diagnosis Procedure".
5.CHECK FUNCTION OF IGNITION COIL-I
CAUTION:
Do the following procedure in the place where ventilation is good without the combustible.
1. Turn ignition switch OFF.
2. Remove fuel pump fuse in IPDM E/R to release fuel pressure. NOTE:
Do not use CONSULT-III to release fuel pressure, or fuel pres-
sure applies again during the following procedure.
3. Start engine.
4. After engine stalls, crank it two or three times to release all fuel pressure.
5. Turn ignition switch OFF.
6. Remove all ignition coil harness connectors to avoid the electri- cal discharge from the ignition coils.
7. Remove ignition coil and spark plug of the cylinder to be checked.
8. Crank engine for 5 seconds or more to remove combustion gas in the cylinder.
9. Connect spark plug and harness connector to ignition coil.
10. 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.
11. Crank engine for about 3 seconds, and check whether spark is
generated between the spark plug and the grounded metal por-
tion.
CAUTION:
BBIA0374E
PBIB1986E
Spark should be generated.
BBIA0380E
PBIB2325E
Revision: March 2010 2008 QX56

P0420, P0430 THREE WAY CATALYST FUNCTIONEC-217
< COMPONENT DIAGNOSIS > [VK56DE]
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OK or NG
OK >> GO TO 5.
NG >> Follow the
EC-13, "
Basic Inspection".
5.CHECK FUEL INJECTOR
1. Stop engine and then turn ignition switch ON.
2. Check voltage between ECM terminals 21, 22, 23, 40, 41, 42, 44, 63 and ground with CONSULT-III or tester.
Refer to Wiring Diagram for fuel injector, EC-439, "
Wiring Dia-
gram - ENGINE CONTROL SYSTEM -".
OK or NG
OK >> GO TO 6.
NG >> Perform EC-411, "
Diagnosis Procedure".
6.CHECK FUNCTION OF IGNITION COIL-I
CAUTION:
Do the following procedure in the place where ventilation is good without the combustible.
1. Turn ignition switch OFF.
2. Remove fuel pump fuse in IPDM E/R to release fuel pressure.
NOTE:
Do not use CONSULT-III to release fuel pressure, or fuel pres-
sure applies again during the following procedure.
3. Start engine.
4. After engine stalls, crank it two or three times to release all fuel pressure.
5. Turn ignition switch OFF.
6. Remove all ignition coil harness connectors to avoid the electri- cal discharge from the ignition coils.
7. Remove ignition coil and spark plug of the cylinder to be checked.
8. Crank engine for 5 seconds or more to remove combustion gas in the cylinder.
9. Connect spark plug and harness connector to ignition coil.
10. 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.
11. 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 coilwithin 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.
OK or NG
OK >> GO TO 10.
Items Specifications
Target idle speed 650 ± 50 rpm (in P or N position)
Ignition timing 15 ± 5° BTDC (in P or N position)
Battery voltage should exist.
PBIB1527E
Spark should be generated.
BBIA0380E
PBIB2325E
Revision: March 2010 2008 QX56