fuel INFINITI QX4 2001 Factory Service Manual

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

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.
SEF427N
SEF943S
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.
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

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
SEF195Y
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

Wiring DiagramNBEC0620
MEC983C
DTC P0460 FUEL LEVEL SENSOR FUNCTION (SLOSH)
Wiring Diagram
EC-408

Diagnostic Procedure=NBEC0621
1 CHECK FUEL LEVEL SENSOR POWER SUPPLY CIRCUIT
1. Turn ignition switch ªOFFº.
2. Disconnect fuel level sensor unit harness connector.
3. Turn ignition switch ªONº.
4. Check voltage between fuel level sensor unit terminal 3 and ground with CONSULT-II or a tester.
SEF993Y
OK or NG
OK©GO TO 3.
NG©GO TO 2.
2 DETECT MALFUNCTIONING PART
Check the following.
IHarness connectors M2, B1
IHarness for open or short between combination meter and fuel level sensor unit
©Repair or replace harness or connectors.
3 CHECK FUEL LEVEL SENSOR GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch ªOFFº.
2. Check harness continuity between fuel level sensor unit terminal 2 and body ground. Refer to Wiring Diagram.
Continuity should exist.
3. Also check harness for short to power.
OK or NG
OK©GO TO 4.
NG©Repair open circuit or short to power in harness or connectors.
4 CHECK FUEL LEVEL SENSOR INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Disconnect ECM harness connector.
2. Check harness continuity between ECM terminal 83 and fuel level sensor terminal 3, ECM terminal 59 and fuel level
sensor unit terminal 2. Refer to Wiring Diagram.
Continuity should exist.
3. Also check harness for short to ground and short to power.
OK or NG
OK©GO TO 6.
NG©GO TO 5.
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DTC P0460 FUEL LEVEL SENSOR FUNCTION (SLOSH)
Diagnostic Procedure
EC-409

5 DETECT MALFUNCTIONING PART
Check the following.
IHarness connectors M2, B1
IHarness connectors M94, F27
IHarness for open or short between ECM and fuel level sensor
©Repair open circuit or short to ground or short to power in harness or connectors.
6 CHECK FUEL LEVEL SENSOR
Refer to EL-108, ªFuel Level Sensor Unit Checkº.
OK or NG
OK©GO TO 7.
NG©Replace fuel level sensor unit.
7 CHECK INTERMITTENT INCIDENT
Refer to ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-140.
©INSPECTION END
DTC P0460 FUEL LEVEL SENSOR FUNCTION (SLOSH)
Diagnostic Procedure (Cont'd)
EC-410

SEF018S
Component Description=NBEC0622The 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 LogicNBEC0623Driving long distances naturally affect fuel gauge level.
This diagnosis detects the fuel gauge malfunction of the gauge not
moving even after a long distance has been driven.
Malfunction is detected when the output signal of the fuel level
sensor does not change within the specified range even though the
vehicle has been driven a long distance.
Possible CauseNBEC0624IHarness or connectors
(The level sensor circuit is open or shorted.)
IFuel level sensor
Overall Function CheckNBEC0625Use this procedure to check the overall function of the fuel level
sensor function. During this check, a 1st trip DTC might not be
confirmed.
WARNING:
When performing following procedure, be sure to observe the
handling of the fuel. Refer to FE-5, ªFuel Tankº.
TESTING CONDITION:
Before starting overall function check, preparation of draining
fuel and refilling fuel is required.
SEF195Y
WITH CONSULT-IINBEC0625S01NOTE:
Start from step 11, if it is possible to confirm that the fuel
cannot be drained by 30(7-7/8 US gal, 6-5/8 Imp gal) in
advance.
1) Prepare a fuel container and a spare hose.
2) Release fuel pressure from fuel line, refer to ªFuel Pressure
Releaseº, EC-39.
3) Remove the fuel feed hose on the fuel level sensor unit.
4) Connect a spare fuel hose where the fuel feed hose was
removed.
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DTC P0461 FUEL LEVEL SENSOR FUNCTION
Component Description
EC-411

5) Turn ignition switch ªOFFº and wait at least 10 seconds then
turn ªONº.
6) Select ªFUEL LEVEL SEº in ªDATA MONITORº mode with
CONSULT-II.
7) Check ªFUEL LEVEL SEº output voltage and note it.
8) Select ªFUEL PUMPº in ªACTIVE TESTº mode with CON-
SULT-II.
9) Touch ªONº and drain fuel approximately 30(7-7/8 US gal,
6-5/8 Imp gal) and stop it.
10) Fill fuel into the fuel tank for 30(7-7/8 US gal, 6-5/8 Imp gal).
11) Check ªFUEL LEVEL SEº output voltage and note it.
12) Check ªFUEL LEVEL SEº output voltage and confirm whether
the voltage changes more than 0.03V during step 7 to 11.
If NG, check the fuel level sensor, refer to EL-108, ªFUEL
LEVEL SENSOR UNIT CHECKº.
SEF615X
WITH GSTNBEC0625S02NOTE:
Start from step 11, if it is possible to confirm that the fuel
cannot be drained by 30(7-7/8 US gal, 6-5/8 Imp gal) in
advance.
1) Prepare a fuel container and a spare hose.
2) Release fuel pressure from fuel line, refer to ªFuel Pressure
Releaseº, EC-39.
3) Remove the fuel feed hose on the fuel level sensor unit.
4) Connect a spare fuel hose where the fuel feed hose was
removed.
5) Turn ignition switch ªOFFº.
6) Set voltmeters probe between ECM terminal 83 (fuel level
sensor signal) and ground.
7) Turn ignition switch ªONº.
8) Check voltage between ECM terminal 83 and ground and note
it.
9) Drain fuel by 30(7-7/8 US gal, 6-5/8 Imp gal) from the fuel
tank using proper equipment.
10) Fill fuel into the fuel tank for 30(7-7/8 US gal, 6-5/8 Imp gal).
11) Confirm that the voltage between ECM terminal 83 and ground
changes more than 0.03V during step8-10.
If NG, check component of fuel level sensor, refer to EL-108,
ªFUEL LEVEL SENSOR UNIT CHECKº.
DTC P0461 FUEL LEVEL SENSOR FUNCTION
Overall Function Check (Cont'd)
EC-412

SEF018S
Component DescriptionNBEC0626The 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 LogicNBEC0627ECM receives two signals from the fuel level sensor circuit.
One is fuel level sensor power supply circuit, and the other is fuel
level sensor ground circuit.
This diagnosis indicates the former, to detect open or short circuit
malfunction.
Malfunction is detected when an excessively low or high voltage is
sent from the sensor is sent to ECM.
Possible CauseNBEC0628IFuel level sensor circuit
(The fuel level sensor circuit is open or shorted.)
IFuel level sensor
DTC Confirmation ProcedureNBEC0629NOTE:
If 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:
Before performing the following procedure, confirm that bat-
tery voltage is more than 11V at ignition switch ªONº.
SEF195Y
WITH CONSULT-IINBEC0629S011) Turn ignition switch ªONº.
2) Select ªDATA MONITORº mode with CONSULT-II.
3) Wait at least 5 seconds.
4) If 1st trip DTC is detected, go to ªDiagnostic Procedureº,
EC-415.
WITH GSTNBEC0629S02Follow the procedure ªWITH CONSULT-IIº above.
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DTC P0464 FUEL LEVEL SENSOR CIRCUIT
Component Description
EC-413