2001 INFINITI QX4 fuel pump

Diagnostic ProcedureNBEC0181
1 CHECK FUEL TANK TEMPERATURE SENSOR POWER SUPPLY CIRCUIT
1. Turn ignition switch ªOFFº.
2. Disconnect fuel level sensor unit and fuel pump harness connector.
SEF751UA
3. Turn ignition switch ªONº.
4. Check voltage between fuel level sensor unit terminal 1 and ground with CONSULT-II or tester.
SEF973Y
OK or NG
OK©GO TO 3.
NG©GO TO 2.
2 DETECT MALFUNCTIONING PART
Check the following.
IHarness connectors B1, M2
IHarness connectors M92, F27
IHarness for open or short between ECM and fuel level sensor unit and fuel pump
©Repair harness or connector.
3 CHECK FUEL TANK TEMPERATURE SENSOR GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch ªOFFº.
2. Check harness continuity between fuel level sensor unit and fuel pump 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.
DTC P0180 FUEL TANK TEMPERATURE SENSOR
Diagnostic Procedure
EC-312

4 CHECK FUEL TANK TEMPERATURE SENSOR
1. Remove fuel level sensor unit.
2. Check resistance between fuel level sensor unit and fuel pump terminals 1 and 2 by heating with hot water or heat gun
as shown in the figure.
SEF974Y
OK or NG
OK©GO TO 5.
NG©Replace fuel level sensor unit.
5 CHECK INTERMITTENT INCIDENT
Refer to ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-140.
©INSPECTION END
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DTC P0180 FUEL TANK TEMPERATURE SENSOR
Diagnostic Procedure (Cont'd)
EC-313

8 CHECK FUEL PRESSURE
1. Install all removed parts.
2. Release fuel pressure to zero. Refer to EC-39.
3. Install fuel pressure gauge and check fuel pressure. Refer to EC-39.
At idle:
Approx. 235 kPa (2.4 kg/cm
2, 34 psi)
OK or NG
OK©GO TO 10.
NG©GO TO 9.
9 DETECT MALFUNCTIONING PART
Check the following.
IFuel pump and circuit (Refer to EC-625.)
IFuel pressure regulator (Refer to EC-40.)
IFuel lines (Refer to MA-16, ªChecking Fuel Linesº.)
IFuel filter for clogging
©Repair or replace.
10 CHECK IGNITION TIMING
Check the following items. Refer to ªBasic Inspectionº, EC-101.
MTBL0655
OK or NG
OK (With CONSULT-II)©GO TO 11.
OK (Without CONSULT-
II)©GO TO 12.
NG©Follow the ªBasic Inspectionº.
DTC P0300 - P0306 NO.6-1CYLINDER MISFIRE, MULTIPLE CYLINDER
MISFIRE
Diagnostic Procedure (Cont'd)
EC-324

18 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 19.
NG©Replace absolute pressure sensor.
19 CHECK FUEL TANK TEMPERATURE SENSOR
1. Remove fuel level sensor unit.
2. Check resistance between fuel level sensor unit and fuel pump terminals 1 and 2 by heating with hot water or heat gun
as shown in the figure.
SEF974Y
OK or NG
OK©GO TO 20.
NG©Replace fuel level sensor unit.
DTC P0440 EVAP CONTROL SYSTEM (SMALL LEAK) (NEGATIVE PRESSURE)
Diagnostic Procedure (Cont'd)
EC-364

20 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 0.5m
(19.7in) onto a hard surface such as a concrete floor; use a new one.
OK or NG
OK©GO TO 21.
NG©Replace EVAP control system pressure sensor.
21 CHECK EVAP PURGE LINE
Check EVAP purge line (pipe, rubber tube, fuel tank and EVAP canister) for cracks or improper connection.
Refer to ªEvaporative Emission Systemº, EC-32.
OK or NG
OK©GO TO 22.
NG©Repair or reconnect the hose.
22 CLEAN EVAP PURGE LINE
Clean EVAP purge line (pipe and rubber tube) using air blower.
©GO TO 23.
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DTC P0440 EVAP CONTROL SYSTEM (SMALL LEAK) (NEGATIVE PRESSURE)
Diagnostic Procedure (Cont'd)
EC-365

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

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

place or refilling/draining fuel until the output voltage condition
of the ªFUEL LEVEL SEº meets within the range above and
leave the vehicle for more than 1 hour. Then start from step 1).
3) Turn ignition switch ªOFFº and wait at least 5 seconds.
4) Turn ignition switch ªONº.
5) Select ªEVAP VERY/SML LEAK P1441º of ªEVAPORATIVE
SYSTEMº in ªDTC WORK SUPPORTº mode with CONSULT-
II.
Follow the instruction displayed.
6) Make sure that ªOKº is displayed.
If ªNGº is displayed, refer to ªDiagnostic Procedureº, EC-529.
NOTE:
IIf the engine speed cannot be maintained within the range
displayed on CONSULT-II screen, go to ªBasic
inspectionº, EC-101.
IMake sure that EVAP hoses are connected to EVAP canis-
ter purge volume control solenoid valve properly.
OVERALL FUNCTION CHECKNBEC0317S05With 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.
SEF462UA
CAUTION:
INever use compressed air, doing so may damage the
EVAP system.
IDo not start engine.
IDo not exceeded 4.12 kPa (0.042 kg/cm
2, 0.6 psi).
1) Attach the EVAP service port adapter securely to the EVAP
service 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 ªONº.
5) Connect GST and select mode 8.
6) Using mode 8 control the EVAP canister vent control valve
(close) and vacuum cut valve bypass valve (open).
7) Apply pressure and make sure the following conditions are
satisfied.
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 diagnostic procedure, EC-529.
NOTE:
For more information, refer to GST instruction manual.
DTC P1441 EVAP CONTROL SYSTEM (VERY SMALL LEAK)
DTC Confirmation Procedure (Cont'd)
EC-528