2001 INFINITI QX4 ignition

Diagnostic ProcedureNBEC0241
1 CHECK RUBBER TUBE
1. Turn ignition switch ªOFFº.
2. Check rubber tube connected to the EVAP control system pressure sensor for clogging, vent, kink, disconnection or
improper connection.
SEF495R
OK or NG
OK©GO TO 2.
NG©Reconnect, repair or replace.
2 RETIGHTEN GROUND SCREWS
Loosen and retighten engine ground screws.
SEF959Y
©GO TO 3.
3 CHECK CONNECTOR
1. Disconnect EVAP control system pressure sensor harness connector.
2. Check sensor harness connector for water.
Water should not exist.
OK or NG
OK©GO TO 4.
NG©Repair or replace harness connector.
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DTC P0450 EVAPORATIVE EMISSION (EVAP) CONTROL SYSTEM PRESSURE
SENSOR
Diagnostic Procedure
EC-385

4 CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR POWER SUPPLY CIRCUIT
1. Turn ignition switch ªONº.
2. Check voltage between EVAP control system pressure sensor terminal 3 and ground with CONSULT-II or tester.
SEF992Y
OK or NG
OK©GO TO 6.
NG©GO TO 5.
5 DETECT MALFUNCTIONING PART
Check the following.
IHarness connectors B101, B43
IHarness connectors B1, M2 and M94, F27
IHarness for open or short between EVAP control system pressure sensor and ECM
©Repair harness or connectors.
6 CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch ªOFFº.
2. Check harness continuity between EVAP control system pressure sensor terminal 1 and engine ground.
Refer to Wiring Diagram.
Continuity should exist.
3. Also check harness for short to power.
OK or NG
OK©GO TO 8.
NG©GO TO 7.
7 DETECT MALFUNCTIONING PART
Check the following.
IHarness connectors B101, B43
IHarness connectors B1, M2 and M94, F27
IHarness for open between EVAP control system pressure sensor and ECM
IHarness for open between EVAP control system pressure sensor and TCM (Transmission Control Module)
©Repair open circuit or short to power in harness or connectors.
DTC P0450 EVAPORATIVE EMISSION (EVAP) CONTROL SYSTEM PRESSURE
SENSOR
Diagnostic Procedure (Cont'd)
EC-386

16 CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR
1. Remove EVAP control system pressure sensor with its harness connector connected.
CAUTION:
INever apply force to the air hole protector of the sensor if equipped.
SEF799W
2. Remove hose from EVAP control system pressure sensor.
3. Turn ignition switch ªONº.
4. Use pump to apply vacuum and pressure to EVAP control system pressure sensor as shown in figure.
CAUTION:
IAlways calibrate the vacuum pump gauge when using it.
IDo not apply below þ20 kPa (þ150 mmHg, þ5.91 inHg) or over 20 kPa (150 mmHg, 5.91 inHg) of pressure.
5. Check input voltage between ECM terminal 84 and ground.
SEF342X
CAUTION:
IDiscard and EVAP control system pressure sensor which has been dropped from a height of more than 0.5
m (19.7 in) onto a hard surface such as a concrete floor; use a new one.
OK or NG
OK©GO TO 17.
NG©Replace EVAP control system pressure sensor.
17 CHECK RUBBER TUBE
Check obstructed rubber tube connected to EVAP canister vent control valve.
OK or NG
OK©GO TO 18.
NG©Clean rubber tube using an air blower, repair or replace rubber tube.
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DTC P0450 EVAPORATIVE EMISSION (EVAP) CONTROL SYSTEM PRESSURE
SENSOR
Diagnostic Procedure (Cont'd)
EC-391

SEF565X
DTC Confirmation ProcedureNBEC0646
SEF566X
SEF874X
SEF567X
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.
SEF915U
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

9 CHECK FOR EVAP LEAK
With CONSULT-II
1. Turn ignition switch ªONº.
2. Select ªEVAP SYSTEM CLOSEº of ªWORK SUPPORTº mode with CONSULT-II.
3. Touch ªSTARTº and apply pressure into the EVAP line until the pressure indicator reaches the middle of the bar graph.
NOTE:
INever use compressed air or a high pressure pump.
IDo not exceed 4.12 kPa (0.042 kg/cm
2, 0.6 psi) of pressure in the system.
PEF917U
4. Using EVAP leak detector, locate the EVAP leak. For the leak detector, refer to the instruction manual for more details.
Refer to ªEVAPORATIVE EMISSION LINE DRAWINGº, EC-36.
SEF200U
OK or NG
OK©GO TO 11.
NG©Repair or replace.
DTC P0455 EVAP CONTROL SYSTEM (GROSS LEAK)
Diagnostic Procedure (Cont'd)
EC-400

10 CHECK FOR EVAP LEAK
Without CONSULT-II
1. Turn ignition switch ªOFFº.
2. Apply 12 volts DC to EVAP canister vent control valve. The valve will close. (Continue to apply 12 volts until the end of
test.)
SEF598U
3. Apply 12 volts DC to vacuum cut valve bypass valve. The valve will open. (Continue to apply 12V until the end of test.)
SEF599U
4. Pressurize the EVAP line using pressure pump with 1.3 to 2.7 kPa (10 to 20 mmHg, 0.39 to 0.79 inHg), then remove
pump and EVAP service port adapter.
NOTE:
INever use compressed air or a high pressure pump.
IDo not exceed 4.12 kPa (0.042 kg/cm
2, 0.6 psi) of pressure in the system.
5. Using EVAP leak detector, locate the EVAP leak. For the leak detector, refer to the instruction manual for more details.
Refer to ªEVAPORATIVE EMISSION LINE DRAWINGº, EC-36.
SEF200U
OK or NG
OK©GO TO 12.
NG©Repair or replace.
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DTC P0455 EVAP CONTROL SYSTEM (GROSS LEAK)
Diagnostic Procedure (Cont'd)
EC-401

16 CHECK ABSOLUTE PRESSURE SENSOR
1. Remove absolute pressure sensor with its harness connector connected.
SEF961Y
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.
SEF300XA
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.
SEF974Y
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