2001 INFINITI QX4 Fuel

SEF194Y
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WITH CONSULT-IINBEC0239S011) Start engine and warm it up to normal operating temperature.
2) Turn ignition switch ªOFFº and wait at least 10 seconds.
3) Turn ignition switch ªONº.
4) Select ªDATA MONITORº mode with CONSULT-II.
5) Make sure that ªFUEL T/TEMP SEº is more than 0ÉC (32ÉF).
6) Start engine and wait at least 20 seconds.
7) If 1st trip DTC is detected, go to ªDiagnostic Procedureº,
EC-385.
WITH GSTNBEC0239S021) Start engine and warm it up to normal operating temperature.
2) Check that voltage between ECM terminal 92 (Fuel tank tem-
perature sensor signal) and ground is less than 4.2V.
3) Turn ignition switch ªOFFº and wait at least 10 seconds.
4) Start engine and wait at least 20 seconds.
5) Select ªMODE 7º with GST.
6) If 1st trip DTC is detected, go to ªDiagnostic Procedureº,
EC-385.
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DTC P0450 EVAPORATIVE EMISSION (EVAP) CONTROL SYSTEM PRESSURE
SENSOR
DTC Confirmation Procedure (Cont'd)
EC-383

On Board Diagnosis LogicNBEC0644NOTE:
If DTC P0455 is displayed with P1448, perform trouble diagno-
sis for DTC P1448 first. (See EC-573.)
This diagnosis detects a very large leak (fuel filler cap fell off etc.)
in EVAP system between the fuel tank and EVAP canister purge
volume control solenoid valve.
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Malfunction is detected when EVAP control system has a very large
leak such as fuel filler cap fell off, EVAP control system does not
operate properly.
CAUTION:
IUse only a genuine NISSAN fuel filler cap as a replace-
ment. If an incorrect fuel filler cap is used, the MIL may
come on.
IIf the fuel filler cap is not tightened properly, the MIL may
come on.
IUse only a genuine NISSAN rubber tube as a replacement.
Possible CauseNBEC0645IFuel filler cap remains open or fails to close.
IIncorrect fuel tank vacuum relief valve
IIncorrect fuel filler cap used
IForeign matter caught in fuel filler cap.
ILeak is in line between intake manifold and EVAP canister
purge volume control solenoid valve.
IForeign matter caught in EVAP canister vent control valve.
IEVAP canister or fuel tank leaks
IEVAP purge line (pipe and rubber tube) leaks
DTC P0455 EVAP CONTROL SYSTEM (GROSS LEAK)
On Board Diagnosis Logic
EC-394

IEVAP purge line rubber tube bent.
IBlocked or bent rubber tube to EVAP control system pressure
sensor
ILoose or disconnected rubber tube
IEVAP canister vent control valve and the circuit
IEVAP canister purge volume control solenoid valve and the
circuit
IAbsolute pressure sensor
IFuel tank temperature sensor
IO-ring of EVAP canister vent control valve is missing or dam-
aged.
IEVAP control system pressure sensor
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DTC P0455 EVAP CONTROL SYSTEM (GROSS LEAK)
Possible Cause (Cont'd)
EC-395

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DTC Confirmation ProcedureNBEC0646
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CAUTION:
Never remove fuel filler cap during the DTC Confirmation Pro-
cedure.
NOTE:
IIf DTC P0455 is displayed with P1448, perform trouble
diagnosis for DTC P1448 first. (See EC-573.)
IMake sure that EVAP hoses are connected to EVAP canis-
ter purge volume control solenoid valve properly.
IIf ªDTC Confirmation Procedureº has been previously
conducted, always turn ignition switch ªOFFº and wait at least
10 seconds before conducting the next test.
TESTING CONDITION:
IPerform ªDTC WORK SUPPORTº when the fuel level is
between 1/4 to 3/4 full and vehicle is placed on flat level
surface.
IOpen engine hood before conducting the following proce-
dures.
WITH CONSULT-IINBEC0646S011) Tighten fuel filler cap securely until ratcheting sound is heard.
2) Turn ignition switch ªONº.
3) Turn ignition switch ªOFFº and wait at least 10 seconds.
4) Turn ignition switch ªONº and select ªDATA MONITORº mode
with CONSULT-II.
5) Make sure that the following conditions are met.
COOLAN TEMP/S: 0 - 70ÉC (32 - 158ÉF)
INT/A TEMP SE: 0 - 60ÉC (32 - 140ÉF)
6) Select ªEVAP SML LEAK P0440/P1440º of ªEVAPORATIVE
SYSTEMº in ªDTC WORK SUPPORTº mode with CONSULT-
II.
Follow the instruction displayed.
NOTE:
If the engine speed cannot be maintained within the range dis-
played on the CONSULT-II screen, go to ªBasic Inspectionº,
EC-101.
7) Make sure that ªOKº is displayed.
If ªNGº is displayed, select ªSELF-DIAG RESULTSº mode and
make sure that ªEVAP GROSS LEAK [P0455]º is displayed. If
it is displayed, refer to ªDiagnostic Procedureº, EC-397.
If P0440 is displayed, perform ªDiagnostic Procedureº for DTC
P0440.
WITH GSTNBEC0646S02NOTE:
Be sure to read the explanation of ªDriving Patternº on EC-66
before driving vehicle.
1) Start engine.
2) Drive vehicle according to ªDriving Patternº, EC-66.
3) Stop vehicle.
4) Select ªMODE 1º with GST.
IIf SRT of EVAP system is not set yet, go to the following step.
IIf SRT of EVAP system is set, the result will be OK.
5) Turn ignition switch ªOFFº and wait at least 10 seconds.
6) Start engine.
It is not necessary to cool engine down before driving.
7) Drive vehicle again according to the ªDriving Patternº, EC-66.
DTC P0455 EVAP CONTROL SYSTEM (GROSS LEAK)
DTC Confirmation Procedure
EC-396

8) Stop vehicle.
9) Select ªMODE 3º with GST.
IIf P0455 is displayed on the screen, go to ªDiagnostic
Procedureº, EC-397.
IIf P0440 or P1440 is displayed on the screen, go to ªDiagnos-
tic Procedureº, for DTC P0440, EC-355.
IIf P1447 is displayed on the screen, go to ªDiagnostic Proce-
dureº for DTC P1447, EC-564.
IIf P0455, P0440, P1440 and P1447 are not displayed on the
screen, go to the following step.
10) Select ªMODE 1º with GST.
IIf SRT of EVAP system is set, the result will be OK.
IIf SRT of EVAP system is not set, go to step 6.
Diagnostic ProcedureNBEC0647
1 CHECK FUEL FILLER CAP DESIGN
1. Turn ignition switch ªOFFº.
2. Check for genuine NISSAN fuel filler cap design.
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OK or NG
OK©GO TO 2.
NG©Replace with genuine NISSAN fuel filler cap.
2 CHECK FUEL FILLER CAP INSTALLATION
Check that the cap is tightened properly by rotating the cap clockwise.
OK or NG
OK©GO TO 3.
NG©IOpen fuel filler cap, then clean cap and fuel filler neck threads using air blower.
IRetighten until ratcheting sound is heard.
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DTC P0455 EVAP CONTROL SYSTEM (GROSS LEAK)
DTC Confirmation Procedure (Cont'd)
EC-397

3 CHECK FUEL FILLER CAP FUNCTION
Check for air releasing sound while opening the fuel filler cap.
OK or NG
OK©GO TO 5.
NG©GO TO 4.
4 CHECK FUEL TANK VACUUM RELIEF VALVE
1. Wipe clean valve housing.
2. Check valve opening pressure and vacuum.
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Pressure:
15.3 - 20.0 kPa (0.156 - 0.204 kg/cm2, 2.22 - 2.90 psi)
Vacuum:
þ6.0 to þ3.3 kPa (þ0.061 to þ0.034 kg/cm
2, þ0.87 to þ0.48 psi)
CAUTION:
Use only a genuine fuel filler cap as a replacement. If an incorrect fuel filler cap is used, the MIL may come on.
OK or NG
OK©GO TO 5.
NG©Replace fuel filler cap with a genuine one.
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 ªEvaporative Emission Systemº, EC-32.
OK or NG
OK©GO TO 6.
NG©Repair or reconnect the hose.
DTC P0455 EVAP CONTROL SYSTEM (GROSS LEAK)
Diagnostic Procedure (Cont'd)
EC-398

16 CHECK ABSOLUTE PRESSURE SENSOR
1. Remove absolute pressure sensor with its harness connector connected.
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2. Remove hose from absolute pressure sensor.
3. Install a vacuum pump to absolute pressure sensor.
4. Turn ignition switch ªONº and check output voltage between ECM terminal 80 and engine ground under the following
conditions.
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CAUTION:
IAlways calibrate the vacuum pump gauge when using it.
IDo not apply below þ93.3 kPa (±700 mmHg, ±27.56 inHg) or over 101.3 kPa (760 mmHg, 29.92 inHg) of pressure.
OK or NG
OK©GO TO 17.
NG©Replace absolute pressure sensor.
17 CHECK FUEL TANK TEMPERATURE SENSOR
1. Remove fuel level sensor unit.
2. Check resistance between fuel level sensor unit and fuel pump terminals 4 and 5 by heating with hot water or heat gun
as shown in the figure.
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OK or NG
OK©GO TO 18.
NG©Replace fuel level sensor unit.
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DTC P0455 EVAP CONTROL SYSTEM (GROSS LEAK)
Diagnostic Procedure (Cont'd)
EC-405

SEF018S
Component DescriptionNBEC0616The 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 ECM.
It consists of two parts, one is mechanical float and the other side
is variable resistor. Fuel level sensor output voltage changes
depending on the movement of the fuel mechanical float.
On Board Diagnostic LogicNBEC0617When 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 malfunction is detected.
Malfunction is detected when even though the vehicle is parked, a
signal being varied is sent from the fuel level sensor to ECM.
Possible CauseNBEC0618IFuel level sensor circuit
(The fuel level sensor circuit is open or shorted.)
IFuel level sensor
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DTC Confirmation ProcedureNBEC0619NOTE:
If ªDTC Confirmation Procedureº has been previously conducted,
always turn ignition switch ªOFFº and wait at least 10 seconds
before conducting the next test.
WITH CONSULT-IINBEC0619S011) Turn ignition switch ªONº.
2) Select ªDATA MONITORº mode with CONSULT-II.
3) Start engine and wait maximum of 2 consecutive minutes.
4) If 1st trip DTC is detected, go to ªDiagnostic Procedureº,
EC-409.
WITH GSTNBEC0619S02Follow the procedure ªWITH CONSULT-IIº above.
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DTC P0460 FUEL LEVEL SENSOR FUNCTION (SLOSH)
Component Description
EC-407