sensor INFINITI QX4 2005 Factory Service Manual

DTC P0456 EVAP CONTROL SYSTEM
EC-357
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Revision: October 20052005 QX56
DTC P0456 EVAP CONTROL SYSTEMPFP:14950
On Board Diagnosis LogicUBS00H5T
This diagnosis detects very small leaks in the EVAP line between fuel tank and EVAP canister purge volume
control solenoid valve, using the intake manifold vacuum in the same way as conventional EVAP small leak
diagnosis.
If ECM judges a leak which corresponds to a very small leak, the very small leak P0456 will be detected.
If ECM judges a leak equivalent to a small leak, EVAP small leak P0442 will be detected.
If ECM judges there are no leaks, the diagnosis will be OK.
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0456
0456Evaporative emission
control system very
small leak (negative
pressure check)

EVAP system has a very small leak.

EVAP system does not operate prop-
erly.

Incorrect fuel tank vacuum relief valve

Incorrect fuel filler cap used

Fuel filler cap remains open or fails to close.

Foreign matter caught in fuel filler cap.

Leak is in line between intake manifold and EVAP
canister purge volume control solenoid valve.

Foreign matter caught in EVAP canister vent con-
trol valve.

EVAP canister or fuel tank leaks

EVAP purge line (pipe and rubber tube) leaks

EVAP purge line rubber tube bent

Loose or disconnected rubber tube

EVAP canister vent control valve and the circuit

EVAP canister purge volume control solenoid
valve and the circuit

Fuel tank temperature sensor

O-ring of EVAP canister vent control valve is miss-
ing or damaged

EVAP canister is saturated with water

EVAP control system pressure sensor

Refueling EVAP vapor cut valve

ORVR system leaks

Fuel level sensor and the circuit

Foreign matter caught in EVAP canister purge vol-
ume control solenoid valve
PBIB1026E

DTC P0456 EVAP CONTROL SYSTEM
EC-363
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9. CHECK IF EVAP CANISTER SATURATED WITH WATER
1. Remove EVAP canister with EVAP canister vent control valve and EVAP control system pressure sensor
attached.
2. Does water drain from the EVAP canister?
Ye s o r N o
Yes >> GO TO 10.
No (With CONSULT-II)>>GO TO 12.
No (Without CONSULT-II)>>GO TO 13.
10. CHECK EVAP CANISTER
Weigh the EVAP canister with the EVAP canister vent control valve and EVAP control system pressure sensor
attached.
The weight should be less than 2.5 kg (5.5 lb).
OK or NG
OK (With CONSULT-II)>>GO TO 12.
OK (Without CONSULT-II)>>GO TO 13.
NG >> GO TO 11.
11 . DETECT MALFUNCTIONING PART
Check the following.

EVAP canister for damage

EVAP hose between EVAP canister and vehicle frame for clogging or poor connection
>> Repair hose or replace EVAP canister.
12. CHECK EVAP CANISTER PURGE VOLUME CONTROL SOLENOID VALVE OPERATION
With CONSULT-II
1. Disconnect vacuum hose to EVAP canister purge volume control solenoid valve at EVAP service port.
2. Start engine.
3. Perform “PURG VOL CONT/V” in “ACTIVE TEST” mode.
4. Touch “Qu” on CONSULT-II screen to increase “PURG VOL
CONT/V” opening to 100%.
5. Check vacuum hose for vacuum when revving engine up to
2,000 rpm.
OK or NG
OK >> GO TO 15.
NG >> GO TO 14.
BBIA0351E
PBIB1678E

EC-364Revision: October 2005
DTC P0456 EVAP CONTROL SYSTEM
2005 QX56
13. CHECK EVAP CANISTER PURGE VOLUME CONTROL SOLENOID VALVE OPERATION
Without CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Stop engine.
3. Disconnect vacuum hose to EVAP canister purge volume control solenoid valve at EVAP service port.
4. Start engine and let it idle for at least 80 seconds.
5. Check vacuum hose for vacuum when revving engine up to 2,000 rpm.
OK or NG
OK >> GO TO 16.
NG >> GO TO 14.
14. CHECK VACUUM HOSE
Check vacuum hoses for clogging or disconnection. Refer to EC-114, "
Vacuum Hose Drawing" .
OK or NG
OK >> GO TO 15.
NG >> Repair or reconnect the hose.
15. CHECK EVAP CANISTER PURGE VOLUME CONTROL SOLENOID VALVE
Refer to EC-323, "
Component Inspection" .
OK or NG
OK >> GO TO 16.
NG >> Replace EVAP canister purge volume control solenoid valve.
16. CHECK FUEL TANK TEMPERATURE SENSOR
Refer to EC-258, "
Component Inspection" .
OK or NG
OK >> GO TO 17.
NG >> Replace fuel level sensor unit.
17. CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR
Refer to EC-330, "
Component Inspection" .
OK or NG
OK >> GO TO 18.
NG >> Replace EVAP control system pressure sensor.
18. CHECK EVAP PURGE LINE
Check EVAP purge line (pipe, rubber tube, fuel tank and EVAP canister) for cracks or improper connection.
Refer to EC-33, "
EVAPORATIVE EMISSION LINE DRAWING" .
OK or NG
OK >> GO TO 19.
NG >> Repair or reconnect the hose.
19. CLEAN EVAP PURGE LINE
Clean EVAP purge line (pipe and rubber tube) using air blower.
>> GO TO 20. Vacuum should exist.

DTC P0456 EVAP CONTROL SYSTEM
EC-365
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20. CHECK EVAP/ORVR LINE
Check EVAP/ORVR line between EVAP canister and fuel tank for clogging, kink, looseness and improper con-
nection. For location, refer to EC-39, "
ON BOARD REFUELING VAPOR RECOVERY (ORVR)" .
OK or NG
OK >> GO TO 21.
NG >> Repair or replace hoses and tubes.
21. CHECK RECIRCULATION LINE
Check recirculation line between filler neck tube and fuel tank for clogging, kink, cracks, looseness and
improper connection.
OK or NG
OK >> GO TO 22.
NG >> Repair or replace hose, tube or filler neck tube.
22. CHECK REFUELING EVAP VAPOR CUT VALVE
Refer to EC-43, "
Component Inspection" .
OK or NG
OK >> GO TO 23.
NG >> Replace refueling EVAP vapor cut valve with fuel tank.
23. CHECK FUEL LEVEL SENSOR
Refer to DI-22, "
Fuel Level Sensor Unit Inspection" .
OK or NG
OK >> GO TO 24.
NG >> Replace fuel level sensor unit.
24. CHECK INTERMITTENT INCIDENT
Refer to EC-156, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
>>INSPECTION END

EC-366Revision: October 2005
DTC P0460 FUEL LEVEL SENSOR
2005 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-163, "
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-367, "
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

DTC P0460 FUEL LEVEL SENSOR
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Diagnostic ProcedureUBS00H60
1. CHECK COMBINATION METER FUNCTION
Refer to DI-5, "
COMBINATION METERS" .
OK or NG
OK >> GO TO 2.
NG >> Go to DI-22, "
Fuel Level Sensor Unit Inspection" .
2. CHECK INTERMITTENT INCIDENT
Refer to EC-156, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
>>INSPECTION END
Removal and InstallationUBS00H61
FUEL LEVEL SENSOR
Refer to FL-5, "FUEL LEVEL SENSOR UNIT, FUEL FILTER AND FUEL PUMP ASSEMBLY" .

EC-368Revision: October 2005
DTC P0461 FUEL LEVEL SENSOR
2005 QX56
DTC P0461 FUEL LEVEL SENSORPFP:25060
Component DescriptionUBS00H62
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 LogicUBS00H63
NOTE:
If DTC P0461 is displayed with DTC U1000 or U1001, first perform the trouble diagnosis for DTC U1000,
U1001. Refer to EC-163, "
DTC U1000, U1001 CAN COMMUNICATION LINE" .
Driving 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.
Overall Function CheckUBS00H64
Use this procedure to check the overall function of the fuel level sensor function. During this check, a 1st trip
DTC might not be confirmed.
WAR NIN G:
When performing following procedure, be sure to observe the handling of the fuel. Refer to FL-9,
"FUEL TANK" .
TESTING CONDITION:
Before starting overall function check, preparation of draining fuel and refilling fuel is required.
WITH CONSULT-II
NOTE:
Start from step 10, 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 EC-93, "
FUEL PRESSURE RELEASE" .
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 OFF and wait at least 10 seconds then turn ON.
BBIA0402E
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0461
0461Fuel level sensor circuit
range/performanceThe output signal of the fuel level sensor
does not change within the specified range
even though the vehicle has been driven a
long distance.

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

DTC P0461 FUEL LEVEL SENSOR
EC-369
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6. Select “FUEL LEVEL SE” in “DATA MONITOR” mode with CON-
SULT-II.
7. Check “FUEL LEVEL SE” output voltage and note it.
8. Select “FUEL PUMP” in “ACTIVE TEST” mode with CONSULT-
II.
9. Touch “ON” and drain fuel approximately 30 (7-7/8 US gal, 6-
5/8 Imp gal) and stop it.
10. Check “FUEL LEVEL SE” output voltage and note it.
11. Fill fuel into the fuel tank for 30 (7-7/8 US gal, 6-5/8 Imp gal).
12. Check “FUEL LEVEL SE” output voltage and note it.
13. Confirm whether the voltage changes more than 0.03V during step 7 to 10 and 10 to 12.
If NG, go to EC-369, "
Diagnostic Procedure" .
WITH GST
NOTE:
Start from step 8, 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 EC-93, "
FUEL PRESSURE RELEASE" .
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 ON.
6. Drain fuel by 30 (7-7/8 US gal, 6-5/8 Imp gal) from the fuel tank using proper equipment.
7. Confirm that the fuel gauge indication varies.
8. Fill fuel into the fuel tank for 30 (7-7/8 US gal, 6-5/8 Imp gal).
9. Confirm that the fuel gauge indication varies.
10. If NG, go to EC-369, "
Diagnostic Procedure" .
Diagnostic ProcedureUBS00H65
1. CHECK COMBINATION METER FUNCTION
Refer to DI-5, "
COMBINATION METERS" .
OK or NG
OK >> GO TO 2.
NG >> Go to DI-22, "
Fuel Level Sensor Unit Inspection" .
2. CHECK INTERMITTENT INCIDENT
Refer to EC-156, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
>>INSPECTION END
Removal and InstallationUBS00H66
FUEL LEVEL SENSOR
Refer to FL-5, "FUEL LEVEL SENSOR UNIT, FUEL FILTER AND FUEL PUMP ASSEMBLY" .
SEF 1 95 Y

EC-370Revision: October 2005
DTC P0462, P0463 FUEL LEVEL SENSOR CIRCUIT
2005 QX56
DTC P0462, P0463 FUEL LEVEL SENSOR CIRCUITPFP:25060
Component DescriptionUBS00H67
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 LogicUBS00H68
NOTE:
If DTC P0462 or P0463 is displayed with DTC U1000 or U1001, first perform the trouble diagnosis for
DTC U1000, U1001. Refer to EC-163, "
DTC U1000, U1001 CAN COMMUNICATION LINE" .
This diagnosis indicates the former, to detect open or short circuit malfunction.
DTC Confirmation ProcedureUBS00H69
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:
Before performing the following procedure, confirm that battery voltage is more than 11V at ignition
switch ON.
WITH CONSULT-II
1. Turn ignition switch ON.
2. Select “DATA MONITOR” mode with CONSULT-II.
3. Wait at least 5 seconds.
4. If 1st trip DTC is detected, go to EC-371, "
Diagnostic Procedure"
.
WITH GST
Follow the procedure “WITH CONSULT-II” above.
BBIA0402E
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0462
0462Fuel level sensor circuit
low inputAn excessively low voltage from the sensor is
sent 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 P0463
0463Fuel level sensor circuit
high inputAn excessively high voltage from the sensor is
sent to ECM.
SEF 1 95 Y

DTC P0462, P0463 FUEL LEVEL SENSOR CIRCUIT
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Revision: October 20052005 QX56
Diagnostic ProcedureUBS00H6A
1. CHECK COMBINATION METER FUNCTION
Refer to DI-5, "
COMBINATION METERS" .
OK or NG
OK >> GO TO 2.
NG >> Go to DI-22, "
Fuel Level Sensor Unit Inspection" .
2. CHECK INTERMITTENT INCIDENT
Refer to EC-156, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
>>INSPECTION END
Removal and InstallationUBS00H6B
FUEL LEVEL SENSOR
Refer to FL-5, "FUEL LEVEL SENSOR UNIT, FUEL FILTER AND FUEL PUMP ASSEMBLY" .