2004 INFINITI QX56 stop start

DTC P0125 ECT SENSOR
EC-179
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Revision: August 20072004 QX56
DTC Confirmation ProcedureUBS00H20
CAUTION:
Be careful not to overheat engine.
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
1. Turn ignition switch ON.
2. Select “DATA MONITOR” mode with CONSULT-II.
3. Check that “COOLAN TEMP/S” is above 10°C (50°F).
If it is above 10°C (50°F), the test result will be OK.
If it is below 10°C (50°F), go to following step.
4. Start engine and run it for 65 minutes at idle speed.
If “COOLAN TEMP/S” increases to more than 10°C (50°F)
within 65 minutes, stop engine because the test result will
be OK.
5. If 1st trip DTC is detected, go to EC-179, "
Diagnostic Procedure"
.
WITH GST
Follow the procedure “WITH CONSULT-II” above.
Diagnostic ProcedureUBS00H21
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.
2. CHECK ENGINE COOLANT TEMPERATURE SENSOR
Refer to EC-180, "
Component Inspection" .
OK or NG
OK >> GO TO 3.
NG >> Replace engine coolant temperature sensor.
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BBIA0354E

DTC P0139, P0159 HO2S2
EC-203
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Revision: August 20072004 QX56
2. CLEAR THE SELF-LEARNING DATA
With CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Select “SELF-LEARNING CONT” in “WORK SUPPORT” mode
with CONSULT-II.
3. Clear the self-learning control coefficient by touching “CLEAR”.
4. Run engine for at least 10 minutes at idle speed.
Is the 1st trip DTC P0171, P0172, P0174 or P0175 detected?
Is it difficult to start engine?
Without CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch OFF.
3. Disconnect mass air flow sensor harness connector, and restart
and run engine for at least 5 seconds at idle speed.
4. Stop engine and reconnect mass air flow sensor harness con-
nector.
5. Make sure DTC P0102 is displayed.
6. Erase the DTC memory. Refer to EC-62, "
HOW TO ERASE
EMISSION-RELATED DIAGNOSTIC INFORMATION" .
7. Make sure DTC P0000 is displayed.
8. Run engine for at least 10 minutes at idle speed.
Is the 1st trip DTC P0171, P0172, P0174 or P0175 detected?
Is it difficult to start engine?
Ye s o r N o
Yes >> Perform trouble diagnosis for DTC P0171, P0174 or P0172, P0175. Refer to EC-208 or EC-217
.
No >> GO TO 3.
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DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION
EC-209
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Revision: August 20072004 QX56
WITH GST
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch OFF and wait at least 10 seconds.
3. Disconnect mass air flow sensor harness connector. Then
restart and run engine for at least 5 seconds at idle speed.
4. Stop engine and reconnect mass air flow sensor harness con-
nector.
5. Select MODE 3 with GST. Make sure DTC P0102 is detected.
6. Select MODE 4 with GST and erase the DTC P0102.
7. Start engine again and let it idle for at least 10 minutes.
8. Select MODE 7 with GST. The 1st trip DTC P0171 or P0174
should be detected at this stage, if a malfunction exists. If so, go
to EC-212, "
Diagnostic Procedure" .
9. If it is difficult to start engine at step 7, the fuel injection system
has a malfunction.
10. Crank engine while depressing accelerator pedal. If engine starts, go to EC-212, "
Diagnostic Procedure" .
If engine does not start, check exhaust and intake air leak visually.
BBIA0368E

EC-218Revision: August 2007
DTC P0172, P0175 FUEL INJECTION SYSTEM FUNCTION
2004 QX56
WITH GST
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch OFF and wait at least 10 seconds.
3. Disconnect mass air flow sensor harness connector. Then
restart and run engine for at least 5 seconds at idle speed.
4. Stop engine and reconnect mass air flow sensor harness con-
nector.
5. Select MODE 3 with GST. Make sure DTC P0102 is detected.
6. Select MODE 4 with GST and erase the DTC P0102.
7. Start engine again and let it idle for at least 10 minutes.
8. Select MODE 7 with GST. The 1st trip DTC P0172 or P0175
should be detected at this stage, if a malfunction exists. If so, go
to EC-221, "
Diagnostic Procedure" .
9. If it is difficult to start engine at step 7, the fuel injection system
has a malfunction.
10. Crank engine while depressing accelerator pedal.
If engine starts, go to EC-221, "
Diagnostic Procedure" . If engine does not start, remove spark plugs and
check for fouling, etc.
BBIA0368E

EC-244Revision: August 2007
DTC P0300 - P0308 MULTIPLE CYLINDER MISFIRE, NO. 1 - 8 CYLINDER MIS-
FIRE
2004 QX56
WITH CONSULT-II
1. Turn ignition switch ON, and select “DATA MONITOR” mode
with CONSULT-II.
2. Start engine and warm it up to normal operating temperature.
3. Turn ignition switch OFF and wait at least 10 seconds.
4. Restart engine and let it idle for about 15 minutes.
5. If 1st trip DTC is detected, go to EC-244, "
Diagnostic Procedure"
.
NOTE:
If 1st trip DTC is not detected during above procedure, performing
the following procedure is advised.
1. Turn ignition switch OFF and wait at least 10 seconds.
2. Start engine and drive the vehicle under the similar conditions to (1st trip) Freeze Frame Data for a certain
time. Refer to the table below.
Hold the accelerator pedal as steady as possible.
The similar conditions to (1st trip) Freeze Frame Data means the vehicle operation that the following con-
ditions should be satisfied at the same time.
The time to driving varies according to the engine speed in the freeze frame data.
WITH GST
Follow the procedure “WITH CONSULT-II” above.
Diagnostic ProcedureUBS00H3S
1. CHECK FOR INTAKE AIR LEAK AND PCV HOSE
1. Start engine and run it at idle speed.
2. Listen for the sound of the intake air leak.
3. Check PCV hose connection.
OK or NG
OK >> GO TO 2.
NG >> Discover air leak location and repair.
2. CHECK FOR EXHAUST SYSTEM CLOGGING
Stop engine and visually check exhaust tube, three way catalyst and muffler for dents.
OK or NG
OK >> GO TO 3.
NG >> Repair or replace it.
PBIB0164E
Engine speed Engine speed in the freeze frame data ± 400 rpm
Vehicle speed Vehicle speed in the freeze frame data ± 10 km/h (6 MPH)
Engine coolant temperature
(T) conditionWhen the freeze frame data shows lower than 70 °C (158 °F),
T should be lower than 70 °C (158 °F).
When the freeze frame data shows higher than or equal to 70 °C (158 °F),
T should be higher than or equal to 70 °C (158 °F).
Engine speed Time
Around 1,000 rpm Approximately 10 minutes
Around 2,000 rpm Approximately 5 minutes
More than 3,000 rpm Approximately 3.5 minutes

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
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PBIB2056E

DTC P0441 EVAP CONTROL SYSTEM
EC-273
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Revision: August 20072004 QX56
9. If NG, go to EC-273, "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-634, "
EVAPORA-
TIVE 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-634, "
EVAPORA-
TIVE 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 P0442 EVAP CONTROL SYSTEM
EC-283
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Revision: August 20072004 QX56
13. CHECK EVAP CANISTER PURGE VOLUME CONTROL SOLENOID VALVE OPERATION
Without CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Stop engine.
3. Disconnect vacuum hose to EVAP canister purge volume control solenoid valve at EVAP service port.
4. Start engine and let it idle for at least 80 seconds.
5. Check vacuum hose for vacuum when revving engine up to 2,000 rpm.
OK or NG
OK >> GO TO 16.
NG >> GO TO 14.
14. CHECK VACUUM HOSE
Check vacuum hoses for clogging or disconnection. Refer to EC-24, "
Vacuum Hose Drawing" .
OK or NG
OK >> GO TO 15.
NG >> Repair or reconnect the hose.
15. CHECK EVAP CANISTER PURGE VOLUME CONTROL SOLENOID VALVE
Refer to EC-290, "
Component Inspection" .
OK or NG
OK >> GO TO 16.
NG >> Replace EVAP canister purge volume control solenoid valve.
16. CHECK FUEL TANK TEMPERATURE SENSOR
Refer to EC-229, "
Component Inspection" .
OK or NG
OK >> GO TO 17.
NG >> Replace fuel level sensor unit.
17. CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR
Refer to EC-301, "
Component Inspection" .
OK or NG
OK >> GO TO 18.
NG >> Replace EVAP control system pressure sensor.
18. CHECK EVAP PURGE LINE
Check EVAP purge line (pipe, rubber tube, fuel tank and EVAP canister) for cracks or improper connection.
Refer to EC-634, "
EVAPORATIVE EMISSION LINE DRAWING" .
OK or NG
OK >> GO TO 19.
NG >> Repair or reconnect the hose.
19. CLEAN EVAP PURGE LINE
Clean EVAP purge line (pipe and rubber tube) using air blower.
>> GO TO 20. Vacuum should exist.