INFINITI QX56 2011 Factory Service Manual

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

EC-308
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P0420, P0430 THREE
WAY CATALYST FUNCTION
3.PERFORM DTC CONFIRMATION PROCEDURE-II
1. Wait 5 seconds at idle.
2. Rev engine between 2,000 and 3,000 rpm and maintain it until “INCMP” of “CATALYST” changes to “CMPLT” (It will take approximately 5 minutes).
Does the indication change to
“CMPLT”?
YES >> GO TO 5.
NO >> GO TO 4.
4.PERFORM DTC CONFIRMATION PROCEDURE AGAIN
1. Stop engine and cool it down to less than 70 °C (158 °F).
2. Perform DTC CONFIRMATION PROCEDURE again.
>> GO TO 2.
5.PERFORM DTC CONFIRMATION PROCEDURE-III
Check 1st trip DTC.
Is 1st trip DTC detected?
YES >> Go to EC-309, "Diagnosis Procedure".
NO >> INSPECTION END
6.PERFORM COMPONENT FUNCTION CHECK
WITH GST
Perform component function check. Refer to EC-308, "
Component Function Check".
NOTE:
Use component function check to check the overall functi on of the three way catalyst (manifold). During this
check, a 1st trip DTC might not be confirmed.
Is the inspection result normal?
YES >> INSPECTION END
NO >> Go to EC-309, "
Diagnosis Procedure"
Component Function CheckINFOID:0000000006217852
1.PERFORM COMPONENT FUNCTION CHECK
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. Check the voltage between ECM harness connector terminals under the following conditions.
Is the inspection result normal?
YES >> INSPECTION END
NO >> Go to EC-309, "
Diagnosis Procedure".
DTC ECM
Condition Voltage
Connector +–
Terminal Terminal
P0420 F110 96
[HO2S2
(bank 1)] 100Keeping engine speed at 2,500 rpm
constant under no load The voltage fluctuation cycle takes more
than 5 seconds.
 1 cycle: 0.6 - 1.0
→ 0 - 0.3 → 0.6 - 1.0
P0430 87
[HO2S2
(bank 2)]
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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
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EC-310
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P0420, P0430 THREE
WAY CATALYST FUNCTION
6. Remove all ignition coil harness connectors to avoi d 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:
When the gap is less than 13 mm (0.52 in), a spark might be generated even if the coil is malfunc-
tioning.
Is the inspection result normal?
YES >> GO TO 10.
NO >> GO TO 7.
7.CHECK FUNCTION OF IGNITION COIL-II
1. Turn ignition switch OFF.
2. Disconnect spark plug and connect a non-malfunctioning spark plug.
3. Crank engine for approximately 3 seconds, and rec heck whether spark is generated between the spark
plug and the grounded metal portion.
Is the inspection result normal?
YES >> GO TO 8.
NO >> Check ignition coil, power transistor and their circuits. Refer to EC-506, "
Diagnosis Procedure".
8.CHECK SPARK PLUG
Check the initial spark plug for fouling, etc.
Is the inspection result normal?
YES >> Replace spark plug(s) with standard type one(s). For spark plug type, refer to EM-132, "
Spark Plug".
NO >> Repair or clean spark plug. Then GO TO 9.
9.CHECK FUNCTION OF IGNITION COIL-III
1. Reconnect the initial spark plugs.
2. Crank engine for approximately 3 seconds, and rec heck whether spark is generated between the spark
plug and the grounded portion.
Is the inspection result normal?
YES >> INSPECTION END Spark should be generated.
JMBIA0066GB
Spark should be generated.
SEF156I
Spark should be generated.
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

EC-312
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P0441 EVAP CONTROL SYSTEM
P0441 EVAP CONTROL SYSTEM
DTC LogicINFOID:0000000006288304
DTC DETECTION LOGIC
NOTE:
If DTC P0441 is displayed with other DTC such
as P2122, P2123, P2127, P2128 or P2138, first perform
trouble diagnosis for other DTC.
In this evaporative emission (EVAP) control system, purge flow occurs during non-closed throttle conditions.
Purge volume is related to air intake volume. Under normal purge conditions (non-closed throttle), the EVAP
canister purge volume control solenoid valve is open to admit purge flow. Purge flow exposes the EVAP con-
trol system pressure sensor to intake manifold vacuum.
Under normal conditions (non-closed throttle), sensor output voltage indicates if pressure drop and purge flow
are adequate. If not, a ma lfunction is determined.
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.
Will CONSULT-III be used?
YES >> GO TO 2.
NO >> GO TO 5.
2.PERFORM DTC CONFIRMATION PROCEDURE-I
PBIB1026E
DTC No. Trouble diagnosis name
(Trouble diagnosis content) DTC detecting condition Possible cause
P0441 EVAP PURG FLOW/MON
(EVAP control system incor-
rect purge flow) EVAP control system does not operate
properly, EVAP control system has a leak
between intake manifold and EVAP control
system pressure sensor.  EVAP canister purge volume control sole-
noid valve stuck closed
 EVAP control system pressure sensor and the circuit
 Loose, disconnected or improper connection of rubber tube
 Blocked rubber tube
 Cracked EVAP canister
 EVAP canister purge volume control sole- noid valve circuit
 Accelerator pedal position sensor
 Blocked purge port
 EVAP canister vent control valve
Revision: 2010 May2011 QX56

P0441 EVAP CONTROL SYSTEMEC-313
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WITH CONSULT-III
TESTING CONDITION:
Always perform test at a temperature of 5 °C (41 °F) or more.
1. Start engine and warm it up to 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 let it idle for at least 70 seconds.
6. Select “PURG FLOW P0441” of “EVAPORATIVE SYS TEM” in “DTC WORK SUPPORT” mode with CON-
SULT-III.
7. Touch “START”.
Is
“COMPLETED” displayed on CONSULT-III screen?
YES >> GO TO 4.
NO >> GO TO 3.
3.PERFORM DTC CONFIRMATION PROCEDURE-II
When the following conditions are met, “TESTING” will be displayed on the CONSULT-III screen. Maintain the
conditions continuously until “TESTING” changes to “COMPLETED”. (It will take at least 35 seconds.)
CAUTION:
Always drive vehicle at a safe speed.
NOTE:
If “TESTING” does not change for a long time, retry from step 2.
Is
“COMPLETED” displayed on CONSULT-III screen?
YES >> GO TO 4.
NO >> Perform DTC CONFIRMATION PROCEDURE again. GO TO 2.
4.PERFORM DTC CONFIRMATION PROCEDURE-III
Touch “SELF-DIAG RESULTS”.
Which is displayed on CONSULT-III screen?
OK >> INSPECTION END
NG >> Proceed to EC-314, "
Diagnosis Procedure".
5.PERFORM COMPONENT FUNCTION CHECK
WITH GST
Perform component function check. Refer to EC-313, "
Component Function Check".
NOTE:
Use component function check to check the overall m onitoring function of the EVAP control system purge flow
monitoring. During this check, a 1s t trip DTC might not be confirmed.
Is the inspection result normal?
YES >> INSPECTION END
NO >> Proceed to EC-314, "
Diagnosis Procedure".
Component Function CheckINFOID:0000000006288305
1.PERFORM COMPONENT FUNCTION CHECK
WITH GST
1. Lift up drive wheels.
2. Start engine (VDC switch OFF) and warm it up to normal operating temperature.
3. Turn ignition switch OFF and wait at least 10 seconds.
4. Start engine and wait at least 70 seconds.
Selector lever Suitable position
VHCL SPEED SE 32 - 120 km/h (20 - 75 MPH)
ENG SPEED 500 - 3,000 rpm
B/FUEL SCHDL 1.3 - 9.0 msec
COOLAN TEMP/S More than 0 °C (32 °F)
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EC-314
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P0441 EVAP CONTROL SYSTEM
5. Set voltmeter probes to ECM harness connector terminals under the following conditions.
6. Check EVAP control system pressure sensor value at idle speed and note it.
7. Establish and maintain the following conditions for at least 1 minute.
8. Verify that EVAP control system pressure sensor
value stays 0.1 V less than the value at idle speed (mea-
sured at step 6) for at least 1 second.
Is the inspection result normal?
YES >> INSPECTION END
NO >> Proceed to EC-314, "
Diagnosis Procedure".
Diagnosis ProcedureINFOID:0000000006288306
1.CHECK EVAP CANISTER
1. Turn ignition switch OFF.
2. Check EVAP canister for cracks.
Is the inspection result normal?
YES-1 >> With CONSULT-III: GO TO 2.
YES-2 >> Without CONSULT-III: GO TO 3.
NO >> Replace EVAP canister. Refer to FL-12, "
Removal and Installation".
2.CHECK PURGE FLOW
WITH CONSULT-III
1. Disconnect vacuum hose connected to EVAP canister purge volume control solenoid valve at EVAP ser-
vice port.
2. Start engine and let it idle.
3. Select “PURG VOL CONT/V” in “A CTIVE TEST” mode with CONSULT-III.
4. Touch “Qd” and “Qu” on CONSULT-III screen to adjust “PURG VOL CONT/V” opening and check vacuum
existence.
Is the inspection result normal?
YES >> GO TO 7.
NO >> GO TO 4.
3.CHECK PURGE FLOW
WITHOUT CONSULT-III
1. Start engine and warm it up to normal operating temperature.
2. Stop engine.
3. Disconnect vacuum hose connected to EVAP canister purge volume control solenoid valve at EVAP ser-
vice port and install vacuum gauge. For the location of EVAP service port, refer to EC-45, "
EVAPORATIVE
EMISSION SYSTEM : System Description".
ECM
Connector +–
Te r m i n a l Te r m i n a l
E80 143
(EVAP control system pressure sensor signal) 150
Air conditioner switch ON
Headlamp switch ON
Rear window defogger switch ON
Engine speed Approx. 3,000 rpm
Gear position Any position other than P, N or R
PURG VOL CONT/V Vacuum 100% Existed0% Not existed
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P0441 EVAP CONTROL SYSTEMEC-315
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4. Start engine and let it idle.
Never depress accelerator pedal even slightly.
5. Check vacuum gauge indication before 60 seconds pass after starting engine.
6. Rev engine up to 2,000 rpm after 100 seconds pass after starting engine.
Is the inspection result normal?
YES >> GO TO 7.
NO >> GO TO 4.
4.CHECK EVAP PURGE LINE
1. Turn ignition switch OFF.
2. Check EVAP purge line for improper connection or disconnection. Refer to FL-10, "
Hydraulic Layout".
Is the inspection result normal?
YES >> GO TO 5.
NO >> Repair EVAP purge line.
5.CHECK EVAP PURGE HOSE AND PURGE PORT
1. Disconnect purge hoses connected to EVAP service port ( A)
and EVAP canister purge volume control solenoid valve ( B).
2. Blow air into each hose and EVAP purge port ( C).
3. Check that air flows freely.
Is the inspection result normal?
YES-1 >> With CONSULT-III: GO TO 6.
YES-2 >> Without CONSULT-III: GO TO 7.
NO >> Repair or clean hoses and/or purge port.
6.CHECK EVAP CANISTER PURGE VO LUME CONTROL SOLENOID VALVE
WITH CONSULT-III
1. Start engine.
2. Perform “PURG VOL CONT/V” in “ACTIVE TEST” mode with CONSULT-III. Check that engine speed var-
ies according to the valve opening.
Does engine speed vary according to the valve opening?
YES >> GO TO 8.
NO >> GO TO 7.
7.CHECK EVAP CANISTER PURGE VO LUME CONTROL SOLENOID VALVE
Refer to EC-320, "
Component Inspection (EVAP Canister Purge Volume Control Solenoid Valve)".
Is the inspection result normal?
Vacuum should not exist.
Vacuum should exist.
SEF367U
SEF368U
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EC-316
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P0441 EVAP CONTROL SYSTEM
YES >> GO TO 8.
NO >> Replace EVAP canister purge volume control solenoid valve. Refer to
FL-10, "
Exploded View".
8.CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR CONNECTOR
1. Disconnect EVAP control system pressure sensor harness connector.
2. Check that water is not inside connectors.
Is the inspection result normal?
YES >> GO TO 9.
NO >> Replace EVAP control system pressure sensor. Refer to FL-10, "
Exploded View".
9.CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR FUNCTION
Refer to EC-336, "
DTC Logic" for DTC P0452, EC-341, "DTC Logic" for DTC P0453.
Is the inspection result normal?
YES >> GO TO 10.
NO >> Replace EVAP control system pressure sensor.
10.CHECK RUBBER TUBE FOR CLOGGING
1. Disconnect rubber tube connected to EV AP canister vent control valve.
2. Check the rubber tube for clogging.
Is the inspection result normal?
YES >> GO TO 11.
NO >> Clean the rubber tube using an air blower.
11 .CHECK EVAP CANISTER VENT CONTROL VALVE
Refer to EC-327, "
Component Inspection (EVAP Canister Vent Control Valve)".
Is the inspection result normal?
YES >> GO TO 12.
NO >> Replace EVAP canister vent control valve.
12.CHECK EVAP PURGE LINE
Inspect EVAP purge line (pipe and rubber tube). Check for evidence of leaks.
Refer to FL-10, "
Hydraulic Layout".
Is the inspection result normal?
YES >> GO TO 13.
NO >> Repair or replace malfunctioning part.
13.CLEAN EVAP PURGE LINE
Clean EVAP purge line (pipe and rubber tube) using air blower.
>> GO TO 14.
14.CHECK INTERMITTENT INCIDENT
Refer to GI-40, "
Intermittent Incident".
>> INSPECTION END
Revision: 2010 May2011 QX56