ignition INFINITI QX4 2005 Factory Service Manual

EC-298Revision: October 2005
DTC P0420, P0430 THREE WAY CATALYST FUNCTION
2005 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

DTC P0420, P0430 THREE WAY CATALYST FUNCTION
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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-300, "
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 55
[HO2S2 (bank 1) signal], 74 [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-300, "
Diagnostic Procedure" .

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

EC-300Revision: October 2005
DTC P0420, P0430 THREE WAY CATALYST FUNCTION
2005 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-72, "
Basic Inspection" .
OK or NG
OK >> GO TO 5.
NG >> Follow the EC-72, "
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)

DTC P0420, P0430 THREE WAY CATALYST FUNCTION
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5. CHECK INJECTORS
1. Stop engine and then turn ignition switch ON.
2. Check voltage between ECM terminals 21, 22, 23, 40, 41, 42,
44, 63 and ground with CONSULT-II or tester.
Refer to Wiring Diagram for Injectors, EC-632, "
Wiring Diagram"
.
OK or NG
OK >> GO TO 6.
NG >> Perform EC-633, "
Diagnostic Procedure" .
6. CHECK FUNCTION OF IGNITION COIL-I
CAUTION:
Do the following procedure in the place where ventilation is good without the combustible.
1. Turn ignition switch OFF.
2. Remove fuel pump fuse in IPDM E/R to release fuel pressure.
NOTE:
Do not use CONSULT-II to release fuel pressure, or fuel pres-
sure applies again during the following procedure.
3. Start engine.
4. After engine stalls, crank it two or three times to release all fuel
pressure.
5. Turn ignition switch OFF.
6. Remove all ignition coil harness connectors to avoid the electri-
cal 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
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 10.
NG >> GO TO 7.Battery voltage should exist.
PBIB1527E
Spark should be generated.
BBIA0380E
PBIB2325E

EC-302Revision: October 2005
DTC P0420, P0430 THREE WAY CATALYST FUNCTION
2005 QX56
7. 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 8.
NG >> Check ignition coil, power transistor and their circuits. Refer to EC-619, "
IGNITION SIGNAL" .
8. CHECK SPARK PLUG
Check the initial spark plug for fouling, etc.
OK or NG
OK >> Replace spark plug(s) with standard type one(s). For
spark plug type, refer to MA-18, "
Changing Spark Plugs"
.
NG >> 1. Repair or clean spark plug.
2. GO TO 9.
9. CHECK FUNCTION OF IGNITION COIL-III
1. Reconnect the initial spark plugs.
2. Crank engine for about three seconds, and recheck whether spark is generated between the spark plug
and the grounded portion.
OK or NG
OK >>INSPECTION END
NG >> Replace spark plug(s) with standard type one(s). For spark plug type, refer to MA-18, "
Changing
Spark Plugs" .
10. CHECK INJECTOR
1. Turn ignition switch OFF.
2. Remove injector assembly.
Refer to EM-29, "
FUEL INJECTOR AND FUEL TUBE" .
Keep fuel hose and all injectors connected to injector gallery.
3. Disconnect all ignition coil harness connectors.
4. Reconnect all injector harness connectors disconnected.
5. Turn ignition switch ON.
Make sure fuel does not drip from injector.
OK or NG
OK (Does not drip.)>>GO TO 11.
NG (Drips.)>>Replace the injector(s) from which fuel is dripping.Spark should be generated.
SEF 1 56 I
Spark should be generated.

EC-304Revision: October 2005
DTC P0441 EVAP CONTROL SYSTEM
2005 QX56
DTC P0441 EVAP CONTROL SYSTEMPFP:14950
System DescriptionUBS00H4J
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.
On Board Diagnosis LogicUBS00H4K
Under normal conditions (non-closed throttle), sensor output voltage indicates if pressure drop and purge flow
are adequate. If not, a malfunction is determined.
DTC Confirmation ProcedureUBS00H4L
CAUTION:
Always drive vehicle at a safe speed.
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:
Always perform test at a temperature of 5°C (41°F) or more.
PBIB1026E
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0441
0441EVAP control system
incorrect purge flowEVAP control system does not operate prop-
erly, EVAP control system has a leak between
intake manifold and EVAP control system pres-
sure sensor.

EVAP canister purge volume control
solenoid valve stuck closed

EVAP control system pressure sensor
and the circuit

Loose, disconnected or improper con-
nection of rubber tube

Blocked rubber tube

Cracked EVAP canister

EVAP canister purge volume control
solenoid valve circuit

Accelerator pedal position sensor

Blocked purge port

EVAP canister vent control valve

DTC P0441 EVAP CONTROL SYSTEM
EC-305
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WITH CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch OFF and wait at least 10 seconds.
3. Start engine and let it idle for at least 70 seconds.
4. Select “PURG FLOW P0441” of “EVAPORATIVE SYSTEM” in “DTC CONFIRMATION” mode with CON-
SULT-II.
5. Touch “START”.
If “COMPLETED” is displayed, go to step 7.
6. When the following conditions are met, “TESTING” will be displayed on the CONSULT-II screen. Maintain
the conditions continuously until “TESTING” changes to “COMPLETED”. (It will take at least 35 seconds.)
If “TESTING” is not changed for a long time, retry from step 2.
7. Make sure that “OK” is displayed after touching “SELF-DIAG RESULTS”. If “NG” is displayed, refer to EC-
306, "Diagnostic Procedure" .
Overall Function CheckUBS00H4M
Use this procedure to check the overall monitoring function of the EVAP control system purge flow monitoring.
During this check, a 1st trip DTC might not be confirmed.
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, wait at least 10 seconds.
4. Start engine and wait at least 70 seconds.
5. Set voltmeter probes to ECM terminals 32 (EVAP control system
pressure sensor signal) and ground.
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 0.1V less than the value at idle speed (mea-
sured at step 6) for at least 1 second.
Selector lever Suitable position
VHCL SPEED SE 32 - 120 km/h (20 - 75 MPH)
ENG SPEED 500 - 3,000 rpm
B/FUEL SCHDL 1.0 - 12.0 msec
COOLAN TEMP/S 70 - 100°C (158 - 212°F)
PBIB0826E
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
PBIB11 09 E

EC-306Revision: October 2005
DTC P0441 EVAP CONTROL SYSTEM
2005 QX56
9. If NG, go to EC-306, "Diagnostic Procedure" .
Diagnostic ProcedureUBS00H4N
1. CHECK EVAP CANISTER
1. Turn ignition switch OFF.
2. Check EVAP canister for cracks.
OK or NG
OK (With CONSULT-II)>>GO TO 2.
OK (Without CONSULT-II)>>GO TO 3.
NG >> Replace EVAP canister.
2. CHECK PURGE FLOW
With CONSULT-II
1. 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-33, "
EVAPORATIVE
EMISSION LINE DRAWING" .
2. Start engine and let it idle.
3. Select “PURG VOL CONT/V” in “ACTIVE TEST” mode with CONSULT-II.
4. Rev engine up to 2,000 rpm.
5. Touch “Qd” and “Qu” on CONSULT-II screen to adjust “PURG
VOL CONT/V” opening and check vacuum existence.
OK or NG
OK >> GO TO 7.
NG >> GO TO 4.
3. CHECK PURGE FLOW
Without CONSULT-II
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-33, "
EVAPORATIVE
EMISSION LINE DRAWING" .
4. Start engine and let it idle.
Do not depress accelerator pedal even slightly.
5. Check vacuum gauge indication before 60 seconds passed after starting engine.
6. Revving engine up to 2,000 rpm after 100 seconds passed after starting engine.
OK or NG
OK >> GO TO 7.
NG >> GO TO 4.
PURG VOL CONT/V Vacuum
100% Should exist.
0% Should not exist.
PBIB1678E
Vacuum should not exist.
Vacuum should exist.

DTC P0441 EVAP CONTROL SYSTEM
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4. CHECK EVAP PURGE LINE
1. Turn ignition switch OFF.
2. Check EVAP purge line for improper connection or disconnection.
Refer to EC-33, "
EVAPORATIVE EMISSION LINE DRAWING" .
OK or NG
OK >> GO TO 5.
NG >> Repair it.
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.
OK or NG
OK (With CONSULT-II)>>GO TO 6.
OK (Without CONSULT-II)>>GO TO 7.
NG >> Repair or clean hoses and/or purge port.
6. CHECK EVAP CANISTER PURGE VOLUME CONTROL SOLENOID VALVE
With CONSULT-II
1. Start engine.
2. Perform “PURG VOL CONT/V” in “ACTIVE TEST” mode with
CONSULT-II. Check that engine speed varies according to the
valve opening.
OK or NG
OK >> GO TO 8.
NG >> GO TO 7.
7. CHECK EVAP CANISTER PURGE VOLUME CONTROL SOLENOID VALVE
Refer to EC-323, "
Component Inspection" .
OK or NG
OK >> GO TO 8.
NG >> Replace EVAP canister purge volume control solenoid valve.
SEF 3 67 U
SEF 3 68 U
PBIB1678E

EC-310Revision: October 2005
DTC P0442 EVAP CONTROL SYSTEM
2005 QX56
CAUTION:

Use only a genuine NISSAN fuel filler cap as a replacement. If an incorrect fuel filler cap is used,
the MIL may come on.

If the fuel filler cap is not tightened properly, the MIL may come on.

Use only a genuine NISSAN rubber tube as a replacement.
DTC Confirmation ProcedureUBS00H4P
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:

Perform “DTC WORK SUPPORT” when the fuel level is between 1/4 and 3/4 full, and vehicle is
placed on flat level surface.

Always perform test at a temperature of 0 to 30°C (32 to 86°F).
WITH CONSULT-II
1. Turn ignition switch ON.
2. Turn ignition switch OFF and wait at least 10 seconds.
3. Turn ignition switch ON and select “DATA MONITOR” mode with CONSULT-II.
4. Make sure that the following conditions are met.
COOLAN TEMP/S: 0 - 70°C (32 - 158°F)
INT/A TEMP SE: 0 - 30°C (32 - 86°F)
5. Select “EVAP SML LEAK P0442/P1442” of “EVAPORATIVE SYSTEM” in “DTC WORK SUPPORT” mode
with CONSULT-II.
Follow the instruction displayed.
NOTE:
If the engine speed cannot be maintained within the range displayed on the CONSULT-II screen, go to
EC-72, "
Basic Inspection" .
6. Make sure that “OK” is displayed.
If “NG” is displayed, refer to EC-311, "
Diagnostic Procedure" .
NOTE:
Make sure that EVAP hoses are connected to EVAP canister
purge volume control solenoid valve properly.
WITH GST
NOTE:
Be sure to read the explanation of EC-59, "
Driving Pattern" before driving vehicle.
1. Start engine.
2. Drive vehicle according to EC-59, "
Driving Pattern" .
PBIB0829E
SEC7 63 C