INFINITI QX56 2007 Factory Service Manual

EC-328
< SERVICE INFORMATION >
DTC P0300 - P0308 MULTIPLE CYLINDER MISFIRE, NO. 1 - 8 CYLINDER MIS-
FIRE
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 coil
within 50cm. Be careful not to get an electrical shock
while checking, because the electrical 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 9.
NG >> GO TO 6.
6.CHECK FUNCTION OF IGNITION COIL-II
1. Turn ignition switch OFF.
2. Disconnect spark plug and connect a known-good spark plug.
3. Crank engine for about 3 seconds, and recheck whether spark is generated between the spark plug and
the grounded metal portion.
OK or NG
OK >> GO TO 7.
NG >> Check ignition coil, power transistor and their circuits. Refer to EC-626
.
7.CHECK SPARK PLUG
Check the initial spark plug for fouling, etc.
OK or NG
OK >> Replace malfunctioning spark plug(s) with standard type
one(s). For spark plug type, refer to EM-29
.
NG >> 1. Repair or clean spark plug.
2. GO TO 8.
8.CHECK FUNCTION OF IGNITION COIL-III
1. Reconnect the initial spark plugs.
2. Crank engine for about 3 seconds, and recheck whether spark is generated between the spark plug and
the grounded portion.
OK or NG
OK >>INSPECTION END
NG >> Replace malfunctioning spark plug(s) with standard type one(s). For spark plug type, refer to EM-
29, "Removal and Installation".
9.CHECK COMPRESSION PRESSURESpark should be generated.
PBIB2325E
Spark should be generated.
SEF156I
Spark should be generated.

DTC P0300 - P0308 MULTIPLE CYLINDER MISFIRE, NO. 1 - 8 CYLINDER MIS-
FIRE
EC-329
< SERVICE INFORMATION >
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Check compression pressure. Refer to EM-64, "On-Vehicle Service".
OK or NG
OK >> GO TO 10.
NG >> Check pistons, piston rings, valves, valve seats and cylinder head gaskets.
10.CHECK FUEL PRESSURE
1. Install all removed parts.
2. Release fuel pressure to zero. Refer to EC-80, "
Fuel Pressure Check" .
3. Install fuel pressure gauge and check fuel pressure. Refer to EC-80, "
Fuel Pressure Check" .
OK or NG
OK >> GO TO 12.
NG >> GO TO 11.
11 .DETECT MALFUNCTIONING PART
Check the following.
• Fuel pump and circuit (Refer to EC-613
.)
• Fuel pressure regulator (Refer to EC-80, "
Fuel Pressure Check" .)
• Fuel lines
• Fuel filter for clogging
>> Repair or replace.
12.CHECK IGNITION TIMING
Check the following items. Refer to EC-71, "
Basic Inspection" .
OK or NG
OK >> GO TO 13.
NG >> Follow the EC-71, "
Basic Inspection" .
13.CHECK A/F SENSOR 1 INPUT SIGNAL
1. Turn ignition switch OFF.
2. Disconnect A/F sensor 1 harness connector.
3. Disconnect ECM harness connector.
4. Check harness continuity between the following terminals.
Refer to Wiring Diagram.At idling: Approximately 350 kPa (3.57 kg/cm
2 , 51 psi)
Items Specifications
Target idle speed 650 ± 50 rpm (in P or N position)
Ignition timing 15 ± 5° BTDC (in P or N position)
A/F sensor 1 terminal ECM terminal
Bank 1135
256
BBIA0376E

EC-330
< SERVICE INFORMATION >
DTC P0300 - P0308 MULTIPLE CYLINDER MISFIRE, NO. 1 - 8 CYLINDER MIS-
FIRE
5. Check harness continuity between the following terminals and ground.
Refer to Wiring Diagram.
6. Also check harness for short to power.
OK or NG
OK >> GO TO 14.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
14.CHECK A/F SENSOR 1 HEATER
Refer to EC-168, "
Component Inspection" .
OK or NG
OK >> GO TO 16.
NG >> GO TO 15.
15.REPLACE AIR FUEL RATIO (A/F) SENSOR 1
Replace malfunctioning air fuel ratio (A/F) sensor 1.
CAUTION:
• Discard any air fuel ratio (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 air fuel ratio (A/F) sensor, clean exhaust system threads (using Oxygen Sensor
Thread Cleaner tool J-43897-18 or J-43897-12) and approved anti-seize lubricant.
>>INSPECTION END
16.CHECK MASS AIR FLOW SENSOR
Check mass air flow sensor signal in “DATA MONITOR” mode with CONSULT-II.
With GST
Check mass air flow sensor signal in Service $01 with GST.
OK or NG
OK >> GO TO 17.
NG >> Check connectors for rusted terminals or loose connections in the mass air flow sensor circuit or
ground. Refer to EC-186
.
17.CHECK SYMPTOM MATRIX CHART
Check items on the rough idle symptom in EC-90, "
Symptom Matrix Chart" .
OK or NG
OK >> GO TO 18.
Bank 2116
275
Continuity should exist.
Bank 1 Bank 2
A/F sensor 1 terminal ECM terminal A/F sensor 1 terminal ECM terminal
135116
256275
Continuity should not exist.
3.0 - 9.0 g·m/sec: at idling
9.0 - 28.0 g·m/sec: at 2,500 rpm
3.0 - 9.0 g·m/sec: at idling
9.0 - 28.0 g·m/sec: at 2,500 rpm

DTC P0300 - P0308 MULTIPLE CYLINDER MISFIRE, NO. 1 - 8 CYLINDER MIS-
FIRE
EC-331
< SERVICE INFORMATION >
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NG >> Repair or replace.
18.ERASE THE 1ST TRIP DTC
Some tests may cause a 1st trip DTC to be set.
Erase the 1st trip DTC from the ECM memory after performing the tests. Refer to EC-49, "
Emission-related
Diagnostic Information" .
>> GO TO 19.
19.CHECK INTERMITTENT INCIDENT
Refer to EC-138
.
>>INSPECTION END

EC-332
< SERVICE INFORMATION >
DTC P0327, P0328, P0332, P0333 KS
DTC P0327, P0328, P0332, P0333 KS
Component DescriptionINFOID:0000000003531825
The knock sensor is attached to the cylinder block. It senses engine
knocking using a piezoelectric element. A knocking vibration from
the cylinder block is sensed as vibrational pressure. This pressure is
converted into a voltage signal and sent to the ECM.
On Board Diagnosis LogicINFOID:0000000003531826
The MIL will not light up for these self-diagnoses.
DTC Confirmation ProcedureINFOID:0000000003531827
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 10V at idle.
WITH CONSULT-II
1. Turn ignition switch ON and select “DATA MONITOR” mode with
CONSULT-II.
2. Start engine and run it for at least 5 seconds at idle speed.
3. If 1st trip DTC is detected, go to EC-334, "
Diagnosis Procedure"
With GST
Follow the procedure “WITH CONSULT-II” above.
PBIB0021E
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0327
0327
(bank 1)Knock sensor circuit low in-
putAn excessively low voltage from the sensor
is sent to ECM.
• Harness or connectors
(The sensor circuit is open or shorted.)
• Knock sensor P0332
0332
(bank 2)
P0328
0328
(bank 1)Knock sensor circuit high in-
putAn excessively high voltage from the sensor
is sent to ECM.
P0333
0333
(bank 2)
SEF058Y

DTC P0327, P0328, P0332, P0333 KS
EC-333
< SERVICE INFORMATION >
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Wiring DiagramINFOID:0000000003531828
Specification data are reference values and are measured between each terminal and ground.
CAUTION:
Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in dam-
age to the ECM's transistor. Use a ground other than ECM terminals, such as the ground.
BBWA2094E

EC-334
< SERVICE INFORMATION >
DTC P0327, P0328, P0332, P0333 KS
Diagnosis Procedure
INFOID:0000000003531829
1.CHECK KNOCK SENSOR INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT-I
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check resistance between ECM terminals 15, 36 and ground. Refer to Wiring Diagram.
NOTE:
It is necessary to use an ohmmeter which can measure more than 10 MΩ.
4. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 5.
NG >> GO TO 2.
2.CHECK KNOCK SENSOR INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT-II
1. Disconnect knock sensor harness connector.
2. Check harness continuity between ECM terminal 15 and knock
sensor (bank1) terminal 1, ECM terminal 36 and knock sensor
(bank 2) terminal 1.
Refer to Wiring Diagram.
3. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 4.
NG >> GO TO 3.
3.DETECT MALFUNCTIONING PART
Check the following.
• Harness connectors F26, F101
• Harness for open or short between ECM and knock sensor
>> Repair open circuit or short to ground or short to power in harness or connectors.
4.CHECK KNOCK SENSOR
Refer to EC-335, "
Component Inspection".
OK or NG
OK >> GO TO 5.
NG >> Replace malfunctioning knock sensor.
5.CHECK GROUND CONNECTIONS
Loosen and retighten three ground screws on the body.
TER-
MI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
15
36W
WKnock sensor (bank 1)
Knock sensor (bank 2)[Engine is running]
• Idle speedApproximately 2.5V
Resistance: Approximately 532 - 588 kΩ [at 20°C (68°F)]
Continuity should exist.
PBIB0021E

DTC P0327, P0328, P0332, P0333 KS
EC-335
< SERVICE INFORMATION >
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Refer to EC-143, "Ground Inspection".
OK or NG
OK >> GO TO 6.
NG >> Repair or replace ground connections.
6.CHECK KNOCK SENSOR SHIELD CIRCUIT FOR OPEN AND SHORT
1. Disconnect knock sensor harness connector.
2. Check harness continuity between knock sensor terminal 2 and ground. Refer to Wiring Diagram.
3. Also check harness for short to power.
OK or NG
OK >> GO TO 8.
NG >> GO TO 7.
7.DETECT MALFUNCTIONING PART
Check the following.
• Harness connectors F26, F101
• Harness connectors F14, E5
• Harness for open or short between knock sensor terminal 2 and ground
>> Repair open circuit or short power in harness or connectors.
8.CHECK INTERMITTENT INCIDENT
Refer to EC-138
.
>>INSPECTION END
Component InspectionINFOID:0000000003531830
KNOCK SENSOR
Check resistance between knock sensor terminal 1 and ground.
NOTE:
It is necessary to use an ohmmeter which can measure more
than 10 MΩ.
CAUTION:
Do not use any knock sensors that have been dropped or phys-
ically damaged. Use only new ones.
Removal and InstallationINFOID:0000000003531831
KNOCK SENSOR
Refer to EM-78.
BBIA0354E
Continuity should exist.
Resistance: Approximately 532 - 588 kΩ [at 20°C (68°F)]
SEF227W

EC-336
< SERVICE INFORMATION >
DTC P0335 CKP SENSOR (POS)
DTC P0335 CKP SENSOR (POS)
Component DescriptionINFOID:0000000003531832
The crankshaft position sensor (POS) is located on the A/T assem-
bly facing the gear teeth (cogs) of the signal plate. It detects the fluc-
tuation of the engine revolution.
The sensor consists of a permanent magnet and Hall IC.
When the engine is running, the high and low parts of the teeth
cause the gap with the sensor to change.
The changing gap causes the magnetic field near the sensor to
change.
Due to the changing magnetic field, the voltage from the sensor
changes.
The ECM receives the voltage signal and detects the fluctuation of
the engine revolution.
ECM receives the signals as shown in the figure.
CONSULT-II Reference Value in Data Monitor ModeINFOID:0000000003531833
Specification data are reference values.
On Board Diagnosis LogicINFOID:0000000003531834
DTC Confirmation ProcedureINFOID:0000000003531835
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 10.5V with igni-
tion switch ON.
WITH CONSULT-II
PBIB0562E
PBIB2448E
MONITOR ITEM CONDITION SPECIFICATION
ENG SPEED • Run engine and compare CONSULT-II value with the tachometer indication.Almost the same speed as the ta-
chometer indication.
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0335
0335Crankshaft position sen-
sor (POS) circuit• The crankshaft position sensor (POS) signal
is not detected by the ECM during the first
few seconds of engine cranking.
• The proper pulse signal from the crankshaft
position sensor (POS) is not sent to ECM
while the engine is running.
• The crankshaft position sensor (POS) signal
is not in the normal pattern during engine run-
ning.• Harness or connectors
(The sensor circuit is open or shorted)
• Crankshaft position sensor (POS)
• Signal plate

DTC P0335 CKP SENSOR (POS)
EC-337
< SERVICE INFORMATION >
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1. Turn ignition switch ON and select “DATA MONITOR” mode with
CONSULT-II.
2. Crank engine for at least 2 seconds and run it for at least 5 sec-
onds at idle speed.
3. If 1st trip DTC is detected, go to EC-339, "
Diagnosis Procedure"
.
WITH GST
Follow the procedure “WITH CONSULT-II” above.
SEF058Y