2011 INFINITI QX56 fuel injector

P0172, P0175 FUEL INJECTION SYSTEM FUNCTION
EC-269
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5. Check the continuity between
A/F sensor 1 harness connector and ground, or ECM harness connector
and ground.
6. Also check harness for short to power.
Is the inspection result normal?
YES >> GO TO 4.
NO >> Repair open circuit, short to ground or short to power in harness or connectors.
4.CHECK FUEL PRESSURE
Check fuel pressure. Refer to EC-153, "
Work Procedure".
Is the inspection result normal?
YES >> GO TO 5.
NO >> Replace fuel filter and fuel pump assembly”. Refer to FL-5, "
Removal and Installation".
5.CHECK MASS AIR FLOW SENSOR
WITH CONSULT-III
1. Install all removed parts.
2. Check “MASS AIR FLOW” in “DATA MONITOR” mode with CONSULT-III. For specification, refer to EC-538, "
Mass Air Flow Sensor".
WITH GST
1. Install all removed parts.
2. Check mass air flow sensor signal in “Service $01” with GST. For specification, refer to EC-538, "
Mass Air Flow Sensor".
Is the measurement value within the specification?
YES >> GO TO 6.
NO >> Check connectors for rusted terminals or loose c onnections in the mass air flow sensor circuit or
grounds. Refer to EC-201, "
Diagnosis Procedure".
6.CHECK FUNCTION OF FUEL INJECTOR
WITH CONSULT-III
1. Start engine.
2. Perform “POWER BALANCE” in “A CTIVE TEST” mode with CONSULT-III.
3. Check that each circuit produces a momentary engine speed drop.
WITHOUT CONSULT-III
1. Start engine and let it idle.
DTC A/F sensor 1 ECM
Continuity
Bank Connector Terminal Connector Terminal
P0171 1 F67 3
F110 88
Existed
490
694
P0174 2 F68 378
480
674
DTC A/F sensor 1 ECM
Continuity Continuity
Bank Connector Terminal Connector Terminal
P0171 1 F67 3
F110 88
Existed Not existed
490
694
P0174 2 F68 378
480
674
Revision: 2010 May2011 QX56

EC-270
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
P0172, P0175 FUEL INJECTION SYSTEM FUNCTION
2. Listen to each fuel injector operating sound.
Is the inspection result normal?
YES >> GO TO 7.
NO >> Perform trouble diagnosis for fuel injector, refer to
EC-
498, "Diagnosis Procedure".
7.CHECK INTERMITTENT INCIDENT
Refer to GI-40, "
Intermittent Incident".
Is the inspection result normal?
YES >> Replace fuel injector. Refer to EM-49, "Removal and Installation".
NO >> Repair or replace malfunctioning part. Clicking sound should be heard.
PBIB3332E
Revision: 2010 May2011 QX56

P0201, P0202, P0203, P0204, P0205, P0206, P0207, P0208 INJECTOR
EC-287
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P0201, P0202, P0203, P0204, P0205,
P0206, P0207, P0208 INJECTOR
DTC LogicINFOID:0000000006217835
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.PRECONDITIONING
1. Turn ignition switch OFF and wait at least 10 seconds.
2. Turn ignition switch ON.
3. Turn ignition switch OFF and wait at least 10 seconds.
TESTING CONDITION:
Before performing the foll owing procedure, comfirm that battery voltage is 11 V or more at idle.
>> GO TO 2.
2.PERFORM DTC CONFIRMATION PROCEDURE
1. Turn ignition switch OFF and wait at least 10 seconds.
2. Start the engine and let it idle at least 30 seconds.
3. Check 1st trip DTC.
Is 1st trip DTC detected?
YES >> Proceed to EC-287, "Diagnosis Procedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006217836
1.PERFORM TROUBLE DIAGNOSIS FOR INJECTOR
Refer to EC-498, "
Component Function Check".
Is inspection result normal?
YES >> Check intermittent incident. Refer to GI-40, "Intermittent Incident".
NO >> Repair or replace error-detected parts.
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0201 No.1 fuel injector circuit ECM detects No. 1 injector circuit
is open or shorted.
 The fuel injector circuit is open or shorted
 Fuel injector
ECM
P0202 No. 2 fuel injector circuit
ECM detects No. 2 injector circuit
is open or shorted.
P0203 No. 3 fuel injector circuit ECM detects No. 3 injector circuit
is open or shorted.
P0204 No. 4 fuel injector circuit ECM detects No. 4 injector circuit
is open or shorted.
P0205 No. 5 fuel injector circuit ECM detects No. 5 injector circuit
is open or shorted.
P0206 No. 6 fuel injector circuit ECM detects No. 6 injector circuit
is open or shorted.
P0207 No. 7 fuel injector circuit ECM detects No. 7 injector circuit
is open or shorted.
P0208 No. 8 fuel injector circuit ECM detects No. 8 injector circuit
is open or shorted.
Revision: 2010 May2011 QX56

P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307, P0308 MISFIRE
EC-291
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P0300, P0301, P0302, P0303, P0304,
P0305, P0306, P0307, P0308 MIS-
FIRE
DTC LogicINFOID:0000000006217840
DTC DETECTION LOGIC
When a misfire occurs, engine speed will fluctuate. If the engine speed fluctuates enough to cause the crank-
shaft position (CKP) sensor signal to vary, ECM can determine that a misfire is occurring.
The misfire detection logic consists of the following two conditions.
1. One Trip Detection Logic (Three Way Catalyst Damage) On the 1st trip that a misfire condition occurs that can damage the three way catalyst (TWC) due to over-
heating, the MIL will blink.
When a misfire condition occurs, the ECM monitors the CKP sensor signal every 200 engine revolutions
for a change.
When the misfire condition decreases to a level t hat will not damage the TWC, the MIL will turn off.
If another misfire condition occurs that can damage the TWC on a second trip, the MIL will blink.
When the misfire condition decreases to a level t hat will not damage the TWC, the MIL will remain on.
If another misfire condition occurs that can damage the TWC, the MIL will begin to blink again.
2. Two Trip Detection Logic (Exhaust quality deterioration) For misfire conditions that will not damage the TWC (but will affect vehicle emissions), the MIL will only
light when the misfire is detected on a second trip. Du ring this condition, the ECM monitors the CKP sen-
sor signal every 1,000 engine revolutions.
A misfire malfunction can be detected in any one cylinder or in multiple cylinders.
DTC CONFIRMATION PROCEDURE
1.PRECONDITIONING
1. Turn ignition switch OFF and wait at least 10 seconds.
2. Turn ignition switch ON.
3. Turn ignition switch OFF and wait at least 10 seconds.
Sensor Input signal to ECM ECM function
Crankshaft position sensor Engine speed On board diagnosis of misfire
DTC No. Trouble diagnosis name
(Trouble diagnosis content) DTC detecting condition Possible cause
P0300 MULTI CYL MISFIRE
(Multiple cylinder misfires detected) Multiple cylinders misfire.
 Improper spark plug
 Insufficient compression
 Incorrect fuel pressure
 The fuel injector circuit is open or shorted
 Fuel injector
 Intake air leakage
 The ignition signal circuit is open or shorted
 Lack of fuel
 Signal plate
 A/F sensor 1
 Incorrect PCV hose connection
P0301
CYL 1 MISFIRE
(No.1 cylinder misfire detected)
No. 1 cylinder misfires.
P0302 CYL 2 MISFIRE
(No. 2 cylinder misfire detected) No. 2 cylinder misfires.
P0303 CYL 3 MISFIRE
(No. 3 cylinder misfire detected) No. 3 cylinder misfires.
P0304 CYL 4 MISFIRE
(No. 4 cylinder misfire detected)
No. 4 cylinder misfires.
P0305 CYL 5 MISFIRE
(No. 5 cylinder misfire detected) No. 5 cylinder misfires.
P0306 CYL 6 MISFIRE
(No. 6 cylinder misfire detected) No. 6 cylinder misfires.
P0307 CYL 7 MISFIRE
(No. 7 cylinder misfire detected)
No. 7 cylinder misfires.
P0308 CYL 8 MISFIRE
(No. 8 cylinder misfire detected) No. 8 cylinder misfires.
Revision: 2010 May2011 QX56

P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307, P0308 MISFIRE
EC-293
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Stop engine and visually check exhaust tube, three way catalyst and muffler for dents.
Is the inspection result normal?
YES-1 >> With CONSULT-III: GO TO 3.
YES-2 >> Without CONSULT-III: GO TO 4.
NO >> Repair or replace malfunctioning part.
3.PERFORM POWER BALANCE TEST
WITH CONSULT-III
1. Start engine.
2. Perform “POWER BALANCE” in “A CTIVE TEST” mode with CONSULT-III.
3. Check that each circuit produces a momentary engine speed drop.
Is the inspection result normal?
YES >> GO TO 9.
NO >> GO TO 4.
4.CHECK FUNCTION OF FUEL INJECTOR-I
1. Start engine and let it idle.
2. Listen to each fuel injector operation.
Is the inspection result normal?
YES >> GO TO 5.
NO >> Perform trouble diagnosis for FUEL INJECTOR, refer to EC-498, "
Diagnosis Procedure".
5.CHECK FUNCTION OF IGNITION COIL-I
CAUTION:
Perform the following procedure in a place with no combustible objects and good ventilation.
1. Turn ignition switch OFF.
2. Remove fuel pump fuse No. in IPDM E/R to release fuel pressure. NOTE:
Do not use CONSULT-III to release fuel pressure, or fuel pressure applies again during the following pro-
cedure.
3. Start engine.
4. After engine stalls, crank it 2 or 3 times to release all fuel pressure.
5. Turn ignition switch OFF.
6. Remove all ignition coil harness connectors to avoid the electrical 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 (0.52 - 0.66 in) between the edge of the spark plug and grounded metal
portion as shown in the figure.
11. Crank engine for approximately 3 seconds, and check whether spark is generated between the spark plug and the grounded
metal portion.
CAUTION:
 Never place the spark plug and the ignition coil within 50
cm (19.7 in) each other. Be careful not to get an electrical
shock while checking, becau se the electrical discharge
voltage becomes 20 kV or more.
 It might damage the ignition coil if the gap of more than 17 mm (0.66 in) is made.
NOTE:
Clicking sound should be heard.
PBIB3332E
Spark should be generated.
JMBIA0066GB
Revision: 2010 May2011 QX56

P0420, P0430 THREE WAY CATALYST FUNCTIONEC-307
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P0420, P0430 THREE WAY CATALYST FUNCTION
DTC LogicINFOID:0000000006217851
DTC DETECTION LOGIC
The ECM monitors the switching frequency ratio of air fuel ratio (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 decr
eases, the heated oxygen sensor 2
switching frequency will increase.
When the frequency ratio of A/F sensor 1 and heated oxygen sensor
2 approaches a specified limit value, the three way catalyst (mani-
fold) malfunction is diagnosed.
DTC CONFIRMATION PROCEDURE
1.INSPECTION START
1. Turn ignition switch OFF and wait at least 10 seconds.
2. Turn ignition switch ON.
3. Turn ignition switch OFF and wait at least 10 seconds.
Will CONSULT-III be used?
YES >> GO TO 2.
NO >> GO TO 6.
2.PERFORM DTC CONFIRMATION PROCEDURE-I
WITH CONSULT-III
TESTING CONDITION:
Do not maintain engine speed for mo re than the specified minutes below.
1. Start engine and warm it up to the normal operating temperature.
2. Turn ignition switch OFF and wait at least 10 seconds.
3. Turn ignition switch ON.
4. Turn ignition switch OFF and wait at least 10 seconds.
5. Start engine and keep the engine speed between 3,500 and 4,000 rpm for at least 1 minute under no load.
6. Let engine idle for 1 minute.
7. Select “DATA MONITOR” mode with CONSULT-III.
8. Check 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).
9. Open engine hood.
10. Select “DTC & SRT CONFIRMATION” then “SRT WORK SUPPORT” mode with CONSULT-III.
11. Rev engine between 2,000 and 3,000 rpm and hold it for 3 consecutive minutes then release the acceler-
ator pedal completely.
12. Check the indication of “CATALYST”.
Which is displayed on CONSULT-III screen?
CMPLT >> GO TO 5.
INCMP >> GO TO 3.
PBIB2055E
DTC No. Trouble diagnosis name
(Trouble diagnosis content) DTC detecting condition Possible cause
P0420 TW CATALYST SYS-B1
[Catalyst system efficiency
below threshold (bank 1)]
 Three way catalyst (manifold) does not
operate properly.
 Three way catalyst (manifold) does not have enough oxygen storage capacity.  Three way catalyst (manifold)
 Exhaust tube
 Intake air leakage
 Fuel injector
 Fuel injector leakage
 Spark plug
 Improper ignition timing
P0430
TW CATALYST SYS-B2
[Catalyst system efficiency
below threshold (bank 2)]
Revision: 2010 May2011 QX56

P0420, P0430 THREE WAY CATALYST FUNCTIONEC-309
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Diagnosis ProcedureINFOID:0000000006217853
1.CHECK EXHAUST SYSTEM
Visually check exhaust tubes and muffler for dents.
Is the inspection result normal?
YES >> GO TO 2.
NO >> Repair or replace malfunctioning part.
2.CHECK EXHAUST GAS LEAKAGE
1. Start engine and run it at idle.
2. Listen for an exhaust gas leakage before the three way catalyst (manifold).
Is exhaust gas leakage detected?
YES >> Repair or replace malfunctioning part.
NO >> GO TO 3.
3.CHECK INTAKE AIR LEAKAGE
Listen for an intake air leakage after the mass air flow sensor.
Is intake air leakage detected?
YES >> Repair or replace malfunctioning part.
NO >> GO TO 4.
4.CHECK IDLE SPEED AND IGNITION TIMING
Check idle speed and ignition timing.
For procedure, refer to EC-530, "
Inspection" and EC-531, "Inspection".
For specification, refer to EC-538, "
Idle Speed" and EC-538, "Ignition Timing".
Is the inspection result normal?
YES >> GO TO 5.
NO >> Follow the EC-139, "
Work Procedure".
5.CHECK FUEL INJECTORS
Refer to EC-498, "
Component Function Check".
Is the inspection result normal?
YES >> GO TO 6.
NO >> Perform EC-498, "
Diagnosis Procedure".
6.CHECK FUNCTION OF IGNITION COIL-I
CAUTION:
Perform the following procedure in a place with no combustible objects and good ventilation.
1. Turn ignition switch OFF.
2. Remove fuel pump fuse in IPDM E/R to release fuel pressure.
NOTE:
 For the fuse number, refer to EC-114, "
Wiring Diagram".
 For the fuse arrangement, refer to PG-140, "
Fuse, Connector and Terminal Arrangement".
 Do not use CONSULT-III to release fuel pressure, or fuel pressure applies again during the following
procedure.
3. Start engine.
4. After engine stalls, crank it 2 or 3 times to release all fuel pressure.
5. Turn ignition switch OFF.
PBIB1216E
Revision: 2010 May2011 QX56

P0420, P0430 THREE WAY CATALYST FUNCTIONEC-311
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NO >> Replace spark plug(s) with standard type one(s). For spark plug type, refer to
EM-132, "Spar k
Plug".
10.CHECK FUEL INJECTOR
1. Turn ignition switch OFF.
2. Remove fuel injector assembly. Refer to EM-49, "
Removal and Installation".
Keep fuel hose and all fuel injectors connected to fuel tube.
3. Disconnect all ignition coil harness connectors.
4. Reconnect all fuel injector harness connectors disconnected.
5. Turn ignition switch ON.
6. Check that fuel does not drip from fuel injector.
Does fuel drip from fuel injector?
YES >> Replace the fuel injector(s) from which fuel is dripping.
NO >> GO TO 11.
11 .CHECK INTERMITTENT INCIDENT
Refer to GI-40, "
Intermittent Incident".
Is the inspection result normal?
YES >> Replace three way catalyst assembly.
NO >> Repair or replace harness or connector.
Revision: 2010 May2011 QX56