engine INFINITI QX56 2004 Factory Service Manual

DTC P0300 - P0308 MULTIPLE CYLINDER MISFIRE, NO. 1 - 8 CYLINDER MIS-
FIRE
EC-249
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Revision: August 20072004 QX56
13. CHECK MASS AIR FLOW SENSOR
With CONSULT-II
Check mass air flow sensor signal in “DATA MONITOR” mode with CONSULT-II.
With GST
Check mass air flow sensor signal in MODE 1 with GST.
OK or NG
OK >> GO TO 14.
NG >> Check connectors for rusted terminals or loose connections in the mass air flow sensor circuit or
engine grounds. Refer to EC-146, "
DTC P0101 MAF SENSOR" .
14. CHECK SYMPTOM MATRIX CHART
Check items on the rough idle symptom in EC-84, "
Symptom Matrix Chart" .
OK or NG
OK >> GO TO 15.
NG >> Repair or replace.
15. 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-62, "
HOW TO ERASE
EMISSION-RELATED DIAGNOSTIC INFORMATION" .
>> GO TO 16.
16. CHECK INTERMITTENT INCIDENT
Refer to EC-127, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
>>INSPECTION END 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

EC-250Revision: August 2007
DTC P0327, P0328, P0332, P0333 KS
2004 QX56
DTC P0327, P0328, P0332, P0333 KSPFP:22060
Component DescriptionUBS00H3T
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 LogicUBS00H3U
The MIL will not light up for these diagnoses.
DTC Confirmation ProcedureUBS00H3V
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-252, "
Diagnostic 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
inputAn 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
inputAn excessively high voltage from the sensor
is sent to ECM.
P0333
0333
(bank 2)
SEF 0 58 Y

EC-252Revision: August 2007
DTC P0327, P0328, P0332, P0333 KS
2004 QX56
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.
Diagnostic ProcedureUBS00H3X
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 body 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-254, "
Component Inspection" .
OK or NG
OK >> GO TO 5.
NG >> Replace knock sensor.
TER-
MINAL
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 P0335 CKP SENSOR (POS)
EC-255
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Revision: August 20072004 QX56
DTC P0335 CKP SENSOR (POS)PFP:23731
Component DescriptionUBS00H40
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.
CONSULT-II Reference Value in Data Monitor ModeUBS00H41
Specification data are reference values.
On Board Diagnosis LogicUBS00H42
DTC Confirmation ProcedureUBS00H43
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
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-257, "
Diagnostic Procedure"
.
WITH GST
Follow the procedure “WITH CONSULT-II” above.
PBIB0562E
MONITOR ITEM CONDITION SPECIFICATION
ENG SPEED

Run engine and compare CONSULT-II value with the tachometer indication.Almost the same speed as the
tachometer indication.
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0335
0335Crankshaft position
sensor (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
running.

Harness or connectors
(The sensor circuit is open or shorted)

Crankshaft position sensor (POS)

Signal plate
SEF 0 58 Y

DTC P0335 CKP SENSOR (POS)
EC-257
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Revision: August 20072004 QX56
Specification data are reference values and are measured between each terminal and ground.
Pulse signal is measured by CONSULT-II.
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.
: Average voltage for pulse signal (Actual pulse signal can be confirmed by oscilloscope.)
Diagnostic ProcedureUBS00H45
1. CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body.
Refer to EC-133, "
Ground Inspection" .
OK or NG
OK >> GO TO 2.
NG >> Repair or replace ground connections.
TER-
MINAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
13 OCrankshaft position sensor
(POS)[Engine is running]

Warm-up condition

Idle speed
NOTE:
The pulse cycle changes depending on rpm at
idle. 1.0 - 2.0V
[Engine is running]

Engine speed is 2,000 rpm.1.0 - 2.0V
PBIB1041E
PBIB1042E
BBIA0354E

DTC P0340 CAMSHAFT POSITION (CMP) SENSOR (PHASE)
EC-261
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Revision: August 20072004 QX56
DTC P0340 CAMSHAFT POSITION (CMP) SENSOR (PHASE)PFP:23731
Component DescriptionUBS00H48
The camshaft position sensor (PHASE) senses the protrusion of
exhaust valve cam sprocket to identify a particular cylinder. The
camshaft position sensor (PHASE) senses the piston position.
When the crankshaft position sensor (POS) system becomes inoper-
ative, the camshaft position sensor (PHASE) provides various con-
trols of engine parts instead, utilizing timing of cylinder identification
signals.
The sensor consists of a permanent magnet and Hall IC.
When 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.
On Board Diagnosis LogicUBS00H49
DTC Confirmation ProcedureUBS00H4A
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
1. Turn ignition switch ON.
2. Select “DATA MONITOR” mode with CONSULT-II.
3. Crank engine for at least 2 seconds and run it for at least 5 sec-
onds at idle speed.
4. If 1st trip DTC is detected, go to EC-263, "
Diagnostic Procedure"
.
If 1st trip DTC is not detected, go to next step.
5. Maintaining engine speed at more than 800 rpm for at least 5
seconds.
6. If 1st trip DTC is detected, go to EC-263, "
Diagnostic Procedure"
.
WITH GST
Follow the procedure “WITH CONSULT-II” above.
PBIB0562E
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0340
0340Camshaft position sen-
sor (PHASE) circuit

The cylinder No. signal is not sent to ECM
for the first few seconds during engine
cranking.

The cylinder No. signal is not sent to ECM
during engine running.

The cylinder No. signal is not in the normal
pattern during engine running.

Harness or connectors
(The sensor circuit is open or shorted)

Camshaft position sensor (PHASE)

Camshaft (Exhaust)

Starter motor (Refer to SC-10, "START-
ING SYSTEM" .)

Starting system circuit (Refer to SC-10,
"STARTING SYSTEM" .)

Dead (Weak) battery
SEF 0 58 Y

DTC P0340 CAMSHAFT POSITION (CMP) SENSOR (PHASE)
EC-263
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Revision: August 20072004 QX56
Specification data are reference values and are measured between each terminal and ground.
Pulse signal is measured by CONSULT-II.
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.
: Average voltage for pulse signal (Actual pulse signal can be confirmed by oscilloscope.)
Diagnostic ProcedureUBS00H4C
1. CHECK STARTING SYSTEM
Turn ignition switch to START position.
Ye s o r N o
Yes >> GO TO 2.
No >> Check starting system. (Refer to SC-10, "
STARTING SYSTEM" .)
2. CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body.
Refer to EC-133, "
Ground Inspection" .
OK or NG
OK >> GO TO 3.
NG >> Repair or replace ground connections.
TER-
MINAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
14 YCamshaft position sensor
(PHASE)[Engine is running]

Warm-up condition

Idle speed
NOTE:
The pulse cycle changes depending on rpm at
idle.1.0 - 4.0V
[Engine is running]

Engine speed is 2,000 rpm.1.0 - 4.0V
PBIB1039E
PBIB1040E
Does the engine turn over?
Does the starter motor operate?
BBIA0354E

DTC P0420, P0430 THREE WAY CATALYST FUNCTION
EC-267
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Revision: August 20072004 QX56
DTC P0420, P0430 THREE WAY CATALYST FUNCTIONPFP:20905
On Board Diagnosis LogicUBS00H4F
The ECM monitors the switching frequency ratio of air fuel sensor
(A/F) sensor 1 and heated oxygen sensor 2.
A three way catalyst (manifold) with high oxygen storage capacity
will indicate a low switching frequency of heated oxygen sensor 2.
As oxygen storage capacity decreases, the heated oxygen sensor 2
switching frequency will increase.
When the frequency ratio of air fuel ratio (A/F) sensor 1 and heated
oxygen sensor 2 approaches a specified limit value, the three way
catalyst (manifold) malfunction is diagnosed.
DTC Confirmation ProcedureUBS00H4G
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.
WITH CONSULT-II
TESTING CONDITION:
Do not hold engine speed for more than the specified minutes below.
1. Turn ignition switch ON and select “DATA MONITOR” mode with
CONSULT-II.
2. Start engine and warm it up to the normal operating tempera-
ture.
3. Turn ignition switch OFF and wait at least 10 seconds.
4. Start engine and keep the engine speed between 3,500 and
4,000 rpm for at least 1 minute under no load.
5. Let engine idle for 1 minute.
6. Make sure that “COOLAN TEMP/S” indicates more than 70°C
(158°F).
If not, warm up engine and go to next step when “COOLAN
TEMP/S” indication reaches to 70°C (158°F).
7. Open engine hood.
PBIB2055E
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0420
0420
(Bank 1)
Catalyst system effi-
ciency below threshold

Three way catalyst (manifold) does not oper-
ate properly.

Three way catalyst (manifold) does not have
enough oxygen storage capacity.

Three way catalyst (manifold)

Exhaust tube

Intake air leaks

Fuel injector

Fuel injector leaks

Spark plug

Improper ignition timing P0430
0430
(Bank 2)
SEF 1 89 Y

EC-268Revision: August 2007
DTC P0420, P0430 THREE WAY CATALYST FUNCTION
2004 QX56
8. Select “DTC & SRT CONFIRMATION” then “SRT WORK SUP-
PORT” mode with CONSULT-II.
9. Rev engine up to 2,000 to 3,000 rpm and hold it for 3 consecu-
tive minutes then release the accelerator pedal completely.
If “INCMP” of “CATALYST” changed to “CMPLT”, go to step 12.
10. Wait 5 seconds at idle.
11. Rev engine up to 2,000 to 3,000 rpm and maintain it until
“INCMP” of “CATALYST” changes to “CMPLT” (It will take
approximately 5 minutes).
If not “CMPLT”, stop engine and cool it down to less than 70°C
(158°F) and then retest from step 1.
12. Select “SELF-DIAG RESULTS” mode with CONSULT-II.
13. Confirm that the 1st trip DTC is not detected.
If the 1st trip DTC is detected, go to EC-269, "
Diagnostic Proce-
dure" .
Overall Function CheckUBS00H4H
Use this procedure to check the overall function of the three way catalyst (manifold). During this check, a 1st
trip DTC might not be confirmed.
WITH GST
1. Start engine and warm it up to the normal operating temperature.
2. Turn ignition switch OFF and wait at least 10 seconds.
3. Start engine and keep the engine speed between 3,500 and 4,000 rpm for at least 1 minute under no load.
4. Let engine idle for 1 minute.
5. Open engine hood.
6. Set voltmeter probe between ECM terminals ECM terminals 74
[HO2S2 (bank 1) signal], 55 [HO2S2 (bank 2) signal] and
ground.
7. Keep engine speed at 2,500 rpm constant under no load.
8. Make sure that the voltage does not vary for more than 5 sec-
onds.
If the voltage fluctuation cycle takes less than 5 seconds, go to
EC-269, "
Diagnostic Procedure" .

1 cycle: 0.6 - 1.0 → 0 - 0.3 → 0.6 - 1.0
PBIB1784E
PBIB1785E
SEF 5 35 Z
PBIB2056E

DTC P0420, P0430 THREE WAY CATALYST FUNCTION
EC-269
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Revision: August 20072004 QX56
Diagnostic ProcedureUBS00H4I
1. CHECK EXHAUST SYSTEM
Visually check exhaust tubes and muffler for dent.
OK or NG
OK >> GO TO 2.
NG >> Repair or replace.
2. CHECK EXHAUST GAS LEAK
1. Start engine and run it at idle.
2. Listen for an exhaust gas leak before the three way catalyst (manifold).
OK or NG
OK >> GO TO 3.
NG >> Repair or replace.
3. CHECK INTAKE AIR LEAK
Listen for an intake air leak after the mass air flow sensor.
OK or NG
OK >> GO TO 4.
NG >> Repair or replace.
4. CHECK IGNITION TIMING
Check the following items. Refer to EC-79, "
Basic Inspection" .
OK or NG
OK >> GO TO 5.
NG >> Follow the EC-79, "
Basic Inspection" .
PBIB1216E
Items Specifications
Target idle speed 650 ± 50 rpm (in P or N position)
Ignition timing 15 ± 5° BTDC (in P or N position)