engine INFINITI QX56 2008 Factory Service Manual

TROUBLE DIAGNOSIS - SPECIFICATION VALUEEC-79
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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

EC-80
< COMPONENT DIAGNOSIS >[VK56DE]
TROUBLE DIAGNOSIS - SPECIFICATION VALUE
OK >>
INSPECTION END
NG >> GO TO 15.
15.DISCONNECT AND RECONNE CT 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.
16.CHECK “A/F ALPHA-B1”, “A/F ALPHA-B2”
1. Start engine.
2. 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 >> INSPECTION END
NG >> Detect malfunctioning part according to EC-481, "
Symptom Matrix Chart" .
17.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 >> INSPECTION END
NG (More than the SP value)>>GO TO 18.
NG (Less than the SP value)>>GO TO 25.
18.DETECT MALFUNCTIONING PART
1. Check for the cause of large engine friction. Refer to the following.
- Engine oil level is too high
- Engine oil viscosity
- Belt tension of power steering, alternat or, A/C compressor, etc. is excessive
- Noise from engine
- Noise from transmission, etc.
2. Check for the cause of insufficient combustion. Refer to the following.
- Valve clearance malfunction
- Intake valve timing control function malfunction
- Camshaft sprocket installation malfunction, etc.
>> Repair or replace malfunctioning part, and then GO TO 30.
19.CHECK INTAKE SYSTEM
Check for the cause of uneven air flow through mass air flow sensor. Refer to the following.
• Crushed air ducts
• Malfunctioning seal of air cleaner element
• Uneven dirt of air cleaner element
• Improper specification of intake air system
OK or NG
OK >> GO TO 21.
NG >> Repair or replace malfunctioning part, and then GO TO 20.
20.CHECK “A/F ALPHA-B1”, “A/F ALPHA-B2”, AND “B/FUEL SCHDL”
Select “A/F ALPHA-B1”, “A/F ALPHA-B2”, and “B/F UEL SCHDL” 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 (“B/FUEL SCHDL” is more, “A/F ALPHA-B1”, “A/F ALPHA-B2” are less than the SP value)>>GO TO 21.
21.DISCONNECT AND RECONNECT MASS AIR FLOW SENSOR HARNESS CONNECTOR
1. Stop the engine.
Revision: March 2010 2008 QX56

TROUBLE DIAGNOSIS - SPECIFICATION VALUEEC-81
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2. Disconnect mass air flow sensor harness connecto
r. Check pin terminal and connector for damage and
then reconnect it again.
>> GO TO 22.
22.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 >> 1. Detect malfunctioning part of mass air flow sensor circuit and repair it. Refer to EC-113 .
2. GO TO 29.
NG >> GO TO 23.
23.CHECK “MAS A/F SE-B1”
Select “MAS A/F SE-B1” in “SPEC” of “DATA MONITOR” mode, and make sure that the indication is within the
SP value.
OK or NG
OK >> GO TO 24.
NG (More than the SP value)>>Replace ma ss air flow sensor, and then GO TO 29.
24.REPLACE ECM
1. Replace ECM.
2. Perform initialization of IVIS(NATS) system and registration of all IVIS(NATS) ignition key IDs. Refer to SEC-8, "
ECM RE-COMMUNICATING FUNCTION : Special Repair Requirement".
3. Perform EC-17, "
VIN Registration" .
4. Perform EC-18, "
Accelerator Pedal Released Position Learning" .
5. Perform EC-18, "
Throttle Valve Closed Position Learning" .
6. Perform EC-18, "
Idle Air Volume Learning" .
>> GO TO 29.
25.CHECK INTAKE SYSTEM
Check for the cause of uneven air flow through mass air flow sensor. Refer to the following.
• Crushed air ducts
• Malfunctioning seal of air cleaner element
• Uneven dirt of air cleaner element
• Improper specification of intake air system
OK or NG
OK >> GO TO 27.
NG >> Repair or replace malfunctioning part, and then GO TO 26.
26.CHECK “B/FUEL SCHDL”
Select “B/FUEL SCHDL” in “SPEC” of “DATA MONITOR” m ode, and make sure that the indication is within the
SP value.
OK or NG
OK >> INSPECTION END
NG (Less than the SP value)>>GO TO 27.
27.CHECK “MAS A/F SE-B1”
Select “MAS A/F SE-B1” in “SPEC” of “DATA MONITOR” mode, and make sure that the indication is within the
SP value.
OK or NG
OK >> GO TO 28.
NG (Less than the SP value)>>Replace ma ss air flow sensor, and then GO TO 30.
28.CHECK INTAKE SYSTEM
Check for the cause of air leak after the mass air flow sensor. Refer to the following.
Revision: March 2010 2008 QX56

POWER SUPPLY AND GROUND CIRCUITEC-83
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POWER SUPPLY AND GROUND CIRCUIT
Diagnosis ProcedureINFOID:0000000001351355
1.INSPECTION START
Start engine.
Is engine running?
Ye s o r N o
Yes >> GO TO 8.
No >> GO TO 2.
2.CHECK ECM POWER SUPPLY CIRCUIT-I
1. Turn ignition switch OFF and then ON.
2. Check voltage between ECM terminal 109 and ground with CONSULT-III or tester.
OK or NG
OK >> GO TO 4.
NG >> GO TO 3.
3.DETECT MALFUNCTIONING PART
Check the following.
• 10A fuse
• Harness for open or short between ECM and fuse
>> Repair harness or connectors.
4.CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body. Refer to EC-86, "
Ground Inspection" .
OK or NG
OK >> GO TO 5.
NG >> Repair or replace ground connections.
5.CHECK ECM GROUND CIRCUIT FOR OPEN AND SHORT-I
1. Disconnect ECM harness connector.
2. Check harness continuity between ECM terminals 1, 115, 116 and ground. Refer to Wiring Diagram.
3. Also check harness for short to power. Voltage: Battery voltage
MBIB0015E
BBIA0354E
Continuity should exist.
Revision: March 2010
2008 QX56

EC-90
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P0011, P0021 IVT CONTROL
P0011, P0021 IVT CONTROL
On Board Diagn
osis LogicINFOID:0000000001351370
FA I L - S A F E M O D E
When the malfunction is detected, the ECM enters fail-safe mode.
DTC Confirmation ProcedureINFOID:0000000001351371
CAUTION:
Always drive at a safe speed.
NOTE:
•If DTC P0011 or P0021 is displayed with DTC P0075, P0081, P1140 or P1145, first perform the trouble
diagnosis for EC-103
or EC-299.
• 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, confir m that battery voltage is between 10V and 16V at
idle.
PROCEDURE FOR MALFUNCTION A
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. Maintain the following conditions for at least 20 consecutive seconds.
DTC No. Trouble diagnosis name Detecting conditionPossible cause
P0011
0011
(Bank 1)
Intake valve timing control
performance A
The alignment of the intake valve timing
control has been misresistered. • Harness or connectors
(Intake valve timing control solenoid
valve circuit is open or shorted.)
• Harness or connectors (Intake valve timing control position
sensor circuit is open or shorted.)
• Intake valve timing control solenoid valve
• Intake valve timing control position sensor
• Crankshaft position sensor (POS)
• Camshaft position sensor (PHASE)
• Accumulation of debris to the signal pick-up portion of the camshaft
sprocket
• Timing chain installation
• Foreign matter caught in the oil groove for intake valve timing control
P0021
0021
(Bank 2)
B
There is a gap between angle of target and
phase-control angle degree.
Detected items
Engine operating condition in fail-safe mode
Intake valve timing control The signal is not energized to the solenoid valve and the valve control does not function
ENG SPEEDMore than 2,000 rpm (A cons tant 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.)
Revision: March 2010
2008 QX56

P0011, P0021 IVT CONTROLEC-91
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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

P0031, P0032, P0051, P0052 A/F SENSOR 1 HEATER
EC-97
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P0031, P0032, P0051, P0052
A/F SENSOR 1 HEATER
DescriptionINFOID:0000000001351384
SYSTEM DESCRIPTION
The ECM performs ON/OFF duty control of the A/F sensor 1 heater corresponding to the engine operating
condition to keep the temperature of A/F sensor 1 element at the specified range.
On Board Diagnosis LogicINFOID:0000000001351378
DTC Confirmation ProcedureINFOID:0000000001351379
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, confi rm that battery voltage is between 10.5V and 16V at
idle.
WITH CONSULT-III
1. Start engine and let it idle for at least 10 seconds.
2. Check 1st trip DTC.
3. If 1st trip DTC is detected, go to EC-97, "
Diagnosis Procedure".
WITH GST
Follow the procedure “WITH CONSULT-III” above.
Diagnosis ProcedureINFOID:0000000001351381
1.CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body.
Sensor Input Signal to ECM ECM functionActuator
Camshaft position sensor (PHASE)
Crankshaft position sensor (POS) Engine speed
Air fuel ratio (A/F) sensor 1
heater controlAir fuel ratio (A/F) sensor 1
heater
Mass air flow sensor Amount of intake air
DTC No. Trouble diagnosis name DTC detecting conditionPossible cause
P0031
0031
(Bank 1) Air fuel ratio (A/F) sensor
1 heater control circuit low The current amperage in the air fuel ratio (A/F) sen-
sor 1 heater circuit is out of the normal range.
(An excessively low voltage signal is sent to ECM
through the air fuel ratio (A/F) sensor 1 heater.) • Harness or connectors
(The A/F sensor 1 heater circuit is
open or shorted.)
• A/F sensor 1 heater
P0051
0051
(Bank 2)
P0032
0032
(Bank 1)
Air fuel ratio (A/F) sensor
1 heater control circuit
high The current amperage in the air fuel ratio (A/F) sen-
sor 1 heater circuit is out of the normal range.
(An excessively high voltage signal is sent to ECM
through the air fuel ratio (A/F) sensor 1 heater.) • Harness or connectors
(The A/F sensor 1 heater circuit is
shorted.)
• A/F sensor 1 heater
P0052
0052
(Bank 2)
Revision: March 2010
2008 QX56

EC-100
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P0037, P0038, P0057,
P0058 HO2S2 HEATER
P0037, P0038, P0057, P0058 HO2S2 HEATER
DescriptionINFOID:0000000001351385
SYSTEM DESCRIPTION
The ECM performs ON/OFF control of the heated oxy gen sensor 2 heater corresponding to the engine speed,
amount of intake air and engine coolant temperature.
OPERATION
On Board Diagn osis LogicINFOID:0000000001351387
DTC Confirmation ProcedureINFOID:0000000001351388
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 pr ocedure, confirm that battery voltage is between 10.5V and 16V at
idle.
WITH CONSULT-III
1. Turn ignition switch ON and select “DATA MONITOR” mode with CONSULT-III.
2. Start engine and warm it up to the normal operating temperature.
3. Turn ignition switch OFF and wait at least 10 seconds.
4. Start the engine and keep the engine speed between 3,500 rpm and 4,000 rpm for at least 1 minute under no load.
5. Let engine idle for 1 minute.
6. Check 1st trip DTC.
Sensor Input signal to ECM ECM function Actuator
Camshaft position sensor (PHASE)
Crankshaft position sensor (POS) Engine speed
Heated oxygen sensor 2
heater controlHeated oxygen sensor 2 heater
Engine coolant temperature sensor Engine coolant temperature
Mass air flow sensor Amount of intake air
Engine speed rpm Heated oxygen sensor 2 heater
Above 3,600 OFF
Below 3,600 rpm after 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 ON
DTC No. Trouble diagnosis name
DTC detecting conditionPossible cause
P0037
0037
(Bank 1) Heated oxygen sensor 2
heater control circuit low The current amperage in the heated oxygen sen-
sor 2 heater circuit is out of the normal range.
(An excessively low voltage signal is sent to ECM
through the heated oxygen sensor 2 heater.) • Harness or connectors
(The heated oxygen sensor 2 heater
circuit is open or shorted.)
• Heated oxygen sensor 2 heater
P0057
0057
(Bank 2)
P0038
0038
(Bank 1)
Heated oxygen sensor 2
heater control circuit high The current amperage in the heated oxygen sen-
sor 2 heater circuit is out of the normal range.
(An excessively high voltage signal is sent to ECM
through the heated oxygen sensor 2 heater.) • Harness or connectors
(The heated oxygen sensor 2 heater
circuit is shorted.)
• Heated oxygen sensor 2 heater
P0058
0058
(Bank 2)
Revision: March 2010
2008 QX56

P0075, P0081 IVT CONTROL SOLENOID VALVEEC-103
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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-106
< COMPONENT DIAGNOSIS >[VK56DE]
P0101 MAF SENSOR
P0101 MAF SENSOR
Component DescriptionINFOID:0000000001351401
The mass air flow sensor is placed in the stream of intake air. It mea-
sures the intake flow rate by measuring a part of the entire intake
flow. The mass air flow sensor c
ontrols the temperature of the hot
wire to a certain amount. The heat generated by the hot wire is
reduced as the intake air flows around it. The more air, the greater
the heat loss.
Therefore, the electric current supplied to the hot wire is changed to
maintain the temperature of the hot wire as air flow increases. The
ECM detects the air flow by means of this current change.
On Board Diagn osis LogicINFOID:0000000001351403
DTC Confirmation ProcedureINFOID:0000000001351404
Perform PROCEDURE FOR MALFUNCTION A first.
If the DTC cannot be confirmed, perform PROCEDURE FOR MALFUNCTION B.
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.
PROCEDURE FOR MALFUNCTION A
NOTE:
If engine will not start or stops soon, wait at leas t 10 seconds with engine stopped (Ignition switch ON) instead
of running engine at idle speed.
With CONSULT-III
1. Start engine and warm it up to normal operating temperature.
2. Run engine for at least 10 seconds at idle speed.
3. Check 1st trip DTC.
4. If 1st trip DTC is detected, go to EC-109, "
Diagnosis Procedure".
With GST
Follow the procedure “With CONSULT-III” above.
PROCEDURE FOR MALFUNCTION B
NOTE:
Check vehicle specifications and VIN, then select the procedure to be performed. (Refer to the table below.)
BBIA0355E
DTC No. Trouble diagnosis name DTC detecting conditionPossible cause
P0101
0101 Mass air flow sensor circuit
range/performance A)
A high voltage from the sensor is sent to ECM
under light load driving condition. • Harness or connectors
(The sensor circuit is open or
shorted.)
• Mass air flow sensor
• EVAP control system pressure sensor
• Intake air temperature sensor
B) A low voltage from the sensor is sent to ECM
under heavy load driving condition. • Harness or connectors
(The sensor circuit is open or
shorted.)
• Intake air leaks
• Mass air flow sensor
• EVAP control system pressure sensor
• Intake air temperature sensor
Revision: March 2010 2008 QX56