2004 INFINITI QX56 ECU

DTC P0442 EVAP CONTROL SYSTEM
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Revision: August 20072004 QX56
5. INSTALL THE PRESSURE PUMP
To locate the EVAP leak, install EVAP service port adapter and pres-
sure pump to EVAP service port securely. For the location of EVAP
service port, refer to EC-634, "
EVAPORATIVE EMISSION LINE
DRAWING" .
NOTE:
Improper installation of the EVAP service port adapter to the EVAP service port may cause leaking.
With CONSULT-II>>GO TO 6.
Without CONSULT-II>>GO TO 7.
BBIA0366E
SEF 9 16 U

DTC P0455 EVAP CONTROL SYSTEM
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Revision: August 20072004 QX56
DTC Confirmation ProcedureUBS00H5R
CAUTION:
Never remove fuel filler cap during the DTC Confirmation Procedure.
NOTE:

Make sure that EVAP hoses are connected to EVAP canister purge volume control solenoid valve
properly.

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.

Open engine hood before conducting the following procedures.
WITH CONSULT-II
1. Tighten fuel filler cap securely until ratcheting sound is heard.
2. Turn ignition switch ON.
3. Turn ignition switch OFF and wait at least 10 seconds.
4. Turn ignition switch ON and select “DATA MONITOR” mode with CONSULT-II.
5. Make sure that the following conditions are met.
COOLAN TEMP/S: 0 - 70°C (32 - 158°F)
INT/A TEMP SE: 0 - 60°C (32 - 140°F)
6. 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-79, "
Basic Inspection" .
7. Make sure that “OK” is displayed.
If “NG” is displayed, select “SELF-DIAG RESULTS” mode and
make sure that “EVAP GROSS LEAK [P0455]” is displayed. If it
is displayed, refer to EC-318, "
Diagnostic Procedure" .
If P0442 is displayed, perform Diagnostic Procedure for DTC
P0442 EC-278, "
Diagnostic Procedure" .
PBIB0829E
SEC7 63 C

DTC P0455 EVAP CONTROL SYSTEM
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Revision: August 20072004 QX56
5. CHECK EVAP PURGE LINE
Check EVAP purge line (pipe, rubber tube, fuel tank and EVAP canister) for cracks, improper connection or
disconnection.
Refer to EC-634, "
EVAPORATIVE EMISSION LINE DRAWING" .
OK or NG
OK >> GO TO 6.
NG >> Repair or reconnect the hose.
6. CLEAN EVAP PURGE LINE
Clean EVAP purge line (pipe and rubber tube) using air blower.
>> GO TO 7.
7. CHECK EVAP CANISTER VENT CONTROL VALVE
Check the following.

EVAP canister vent control valve is installed properly.
Refer to EC-637, "
Removal and Installation" .

EVAP canister vent control valve.
Refer to EC-297, "
Component Inspection" .
OK or NG
OK >> GO TO 8.
NG >> Repair or replace EVAP canister vent control valve and O-ring.
8. INSTALL THE PRESSURE PUMP
To locate the EVAP leak, install EVAP service port adapter and pres-
sure pump to EVAP service port securely.
NOTE:
Improper installation of the EVAP service port adapter to the
EVAP service port may cause leaking.
With CONSULT-II>>GO TO 9.
Without CONSULT-II>>GO TO 10.
BBIA0366E
SEF 9 16 U

EC-326Revision: August 2007
DTC P0456 EVAP CONTROL SYSTEM
2004 QX56
Overall Function CheckUBS00H5V
WITH GST
Use this procedure to check the overall function of the EVAP very small leak function. During this check, a 1st
trip DTC might not be confirmed.
CAUTION:

Do not use compressed air, doing so may damage the EVAP system.

Do not start engine.

Do not exceeded 4.12 kPa (0.042 kg/cm2 , 0.6 psi).
1. Attach the EVAP service port adapter securely to the EVAP ser-
vice port.
2. Set the pressure pump and a hose.
3. Also set a vacuum gauge via 3-way connector and a hose.
4. Turn ignition switch ON.
5. Connect GST and select MODE 8.
6. Using mode 8 control the EVAP canister vent control valve
(close).
7. Apply pressure and make sure the following conditions are sat-
isfied.
Pressure to be applied: 2.7 kPa (20 mmHg, 0.79 inHg)
Time to be waited after the pressure drawn in to the EVAP
system and the pressure to be dropped: 60 seconds and
the pressure should not be dropped more than 0.4 kPa (3 mmHg, 0.12 inHg).
If NG, go to EC-327, "
Diagnostic Procedure" .
If OK, go to next step.
8. Disconnect GST.
9. Start engine and warm it up to normal operating temperature.
10. Turn ignition switch OFF and wait at least 10 seconds.
11. Restart engine and let it idle for 90 seconds.
12. Keep engine speed at 2,000 rpm for 30 seconds.
13. Turn ignition switch OFF.
NOTE:
For more information, refer to GST instruction manual.
BBIA0366E
SEF 4 62 UI

EC-328Revision: August 2007
DTC P0456 EVAP CONTROL SYSTEM
2004 QX56
5. INSTALL THE PRESSURE PUMP
To locate the EVAP leak, install EVAP service port adapter and pres-
sure pump to EVAP service port securely. For the location of EVAP
service port, refer to EC-634, "
EVAPORATIVE EMISSION LINE
DRAWING" .
NOTE:
Improper installation of the EVAP service port adapter to the EVAP service port may cause leaking.
With CONSULT-II>>GO TO 6.
Without CONSULT-II>>GO TO 7.
BBIA0366E
SEF 9 16 U

EC-334Revision: August 2007
DTC P0460 FUEL LEVEL SENSOR
2004 QX56
DTC P0460 FUEL LEVEL SENSORPFP:25060
Component DescriptionUBS00H5X
The fuel level sensor is mounted in the fuel level sensor unit. The
sensor detects a fuel level in the fuel tank and transmits a signal to
the combination meter. The combination meter sends the fuel level
sensor signal to the ECM through CAN communication line.
It consists of two parts, one is mechanical float and the other is vari-
able resistor. Fuel level sensor output voltage changes depending on
the movement of the fuel mechanical float.
On Board Diagnosis LogicUBS00H5Y
NOTE:
If DTC P0460 is displayed with DTC U1000 or U1001, first perform the trouble diagnosis for DTC U1000,
U1001. Refer to EC-135, "
DTC U1000, U1001 CAN COMMUNICATION LINE" .
When the vehicle is parked, naturally the fuel level in the fuel tank is stable. It means that output signal of the
fuel level sensor does not change. If ECM senses sloshing signal from the sensor, fuel level sensor malfunc-
tion is detected.
DTC Confirmation ProcedureUBS00H5Z
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. Start engine and wait maximum of 2 consecutive minutes.
4. If 1st trip DTC is detected, go to EC-335, "
Diagnostic Procedure"
.
WITH GST
Follow the procedure “WITH CONSULT-II” above.
BBIA0402E
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0460
0460Fuel level sensor circuit
noiseEven though the vehicle is parked, a signal
being varied is sent from the fuel level sensor
to ECM.

Harness or connectors
(The CAN communication line is open or
shorted)

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

Combination meter

Fuel level sensor
SEF 1 95 Y

EC-340Revision: August 2007
DTC P0500 VSS
2004 QX56
DTC P0500 VSSPFP:32702
DescriptionUBS00H6C
NOTE:
If DTC P0500 is displayed with DTC U1000 or U1001, first perform the trouble diagnosis for DTC U1000,
U1001. Refer to EC-135, "
DTC U1000, U1001 CAN COMMUNICATION LINE" .
The vehicle speed signal is sent to the combination meter from the “ABS actuator and electric unit (control
unit)” by CAN communication line. The c combination meter then sends a signal to the ECM by CAN commu-
nication line.
On Board Diagnosis LogicUBS00H6D
DTC Confirmation ProcedureUBS00H6E
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:
Steps 1 and 2 may be conducted with the drive wheels lifted in the shop or by driving the vehicle. If a
road test is expected to be easier, it is unnecessary to lift the vehicle.
WITH CONSULT-II
1. Start engine (VDC switch OFF).
2. Read “VHCL SPEED SE” in “DATA MONITOR” mode with CONSULT-II. The vehicle speed on CONSULT-
II should exceed 10 km/h (6 MPH) when rotating wheels with suitable gear position.
If NG, go to EC-341, "
Diagnostic Procedure" .
If OK, go to following step.
3. Select “DATA MONITOR” mode with CONSULT-II.
4. Warm engine up to normal operating temperature.
5. Maintain the following conditions for at least 60 consecutive sec-
onds.
6. If 1st trip DTC is detected, go to EC-341, "
Diagnostic Procedure"
.
Overall Function CheckUBS00H6F
Use this procedure to check the overall function of the vehicle speed sensor circuit. During this check, a 1st
trip DTC might not be confirmed.
WITH GST
1. Lift up drive wheels.
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0500
0500Vehicle speed sensorThe almost 0 km/h (0 MPH) signal from
vehicle speed sensor is sent to ECM
even when vehicle is being driven.

Harness or connectors
(The CAN communication line is open or
shorted)

Harness or connectors
(The vehicle speed signal circuit is open or
shorted)

Wheel sensor

Combination meter

ABS actuator and electric unit (control unit)
ENG SPEED More than 1,600 rpm
COOLAN TEMP/S More than 70°C (158°F)
B/FUEL SCHDL More than 6.9 msec
Selector lever Except P or N position
PW/ST SIGNAL OFF
SEF 1 96 Y

EC-430Revision: August 2007
DTC P1271, P1281 A/F SENSOR 1
2004 QX56
3. Check “A/F SEN1 (B1)” or “A/F SEN1 (B2)” indication.
If the indication is constantly approx. 0V, go to EC-434, "
Diag-
nostic Procedure" .
If the indication is not constantly approx. 0V, go to next step.
4. Turn ignition switch OFF, wait at least 10 seconds and then
restart engine.
5. Drive and accelerate vehicle to more than 40 km/h (25 MPH)
within 20 seconds after restarting engine.
6. Maintain the following conditions for about 20 consecutive sec-
onds.
NOTE:

Keep the accelerator pedal as steady as possible during the cruising.

If this procedure is not completed within 1 minute after restarting engine at step 4, return to step
4.
7. If 1st trip DTC is displayed, go to EC-434, "
Diagnostic Procedure" .
WITH GST
Follow the procedure “WITH CONSULT-II” above.
ENG SPEED 1,000 - 3,200 rpm
VHCL SPEED SE More than 40 km/h (25 MPH)
B/FUEL SCHDL 1.5 - 9.0 msec
Gear position Suitable position
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