2010 INFINITI QX56 fuel pressure

EC-256
< COMPONENT DIAGNOSIS >[VK56DE]
P0455 EVAP CONTROL SYSTEM
2. Check for genuine NISSAN fuel filler cap design.
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 proper ly by rotating the cap clockwise.
OK or NG
OK >> GO TO 3.
NG >> 1. Open fuel filler cap, then clean cap and fuel filler neck threads using air blower.
2. Retighten until ratcheting sound is heard.
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
Refer to EC-268, "
Component Inspection".
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 EC-37, "
Description".
OK or NG
OK >> GO TO 6.
NG >> Repair or reconnect the hose.
6.CLEAN EVAP PURGE LINE
Clean EVAP purge line (pipe and rubber tube) using air blower.
>> GO TO 7.
7.CHECK EVAP CANISTER VENT CONTROL VALVE
Check the following.
• EVAP canister vent control valve is installed properly. Refer to EC-493, "
Removal and Installation".
• EVAP canister vent control valve. Refer to EC-236, "
Component Inspection".
OK or NG
OK >> GO TO 8.
NG >> Repair or replace EVAP cani ster vent control valve and O-ring.
8.INSTALL THE PRESSURE PUMP
SEF915U
Revision: April 20092010 QX56

P0455 EVAP CONTROL SYSTEMEC-259
< COMPONENT DIAGNOSIS > [VK56DE]
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OK (With CONSULT-III)>>GO TO 14.
OK (Without CONSULT-III)>>GO TO 15.
NG >> Repair or reconnect the hose.
14.CHECK EVAP CANISTER PURGE VOLUME CONTROL SOLENOID VALVE
With CONSULT-III
1. Start engine.
2. Perform “PURG VOL CONT/V” in “ACTIVE TEST” mode with CONSULT-III. Check that engine speed var-
ies according to the valve opening.
OK or NG
OK >> GO TO 16.
NG >> GO TO 15.
15.CHECK EVAP CANISTER PURGE VOLUME CONTROL SOLENOID VALVE
Refer to EC-233, "
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-184, "
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-243, "
Component Inspection".
OK or NG
OK >> GO TO 18.
NG >> Replace EVAP control system pressure sensor.
18.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-412
.
OK or NG
OK >> GO TO 19.
NG >> Repair or replace hoses and tubes.
19.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 20.
NG >> Repair or replace hose, tube or filler neck tube.
20.CHECK REFUELING EVAP VAPOR CUT VALVE
Refer to EC-414, "
Component Inspection".
OK or NG
OK >> GO TO 21.
NG >> Replace refueling EVAP vapor cut valve with fuel tank.
21.CHECK INTERMITTENT INCIDENT
Refer to GI-35, "
How to Check Terminal" and GI-38, "Intermittent Incident".
>> INSPECTION END
Revision: April 20092010 QX56

EC-260
< COMPONENT DIAGNOSIS >[VK56DE]
P0455 EVAP CONTROL SYSTEM
Component Inspection
INFOID:0000000005149280
FUEL TANK VACUUM RELIEF VALVE (BUILT INTO FUEL FILLER CAP)
1. Wipe clean valve housing.
2. Check valve opening pressure and vacuum.
3. If out of specification, replace fuel filler cap as an assembly.
CAUTION:
Use only a genuine fuel filler cap as a replacement. If an incor-
rect fuel filler cap is used, the MIL may come on.
SEF445Y
Pressure:
15.3 - 20.0 kPa (0.156 - 0.204 kg/cm2, 2.22 -
2.90 psi)
Vacuum: −6.0 to −3.3 kPa (− 0.061 to −0.034 kg/cm
2,
− 0.87 to −0.48 psi)
SEF943S
Revision: April 20092010 QX56

P0456 EVAP CONTROL SYSTEMEC-261
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P0456 EVAP CONTROL SYSTEM
On Board Diagnosis LogicINFOID:0000000005149281
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.
CAUTION:
• Use only a genuine NISSAN fuel filler cap as a replacemen t. If an incorrect fuel filler cap is used, the
MIL may come on.
• If the fuel filler cap is not tigh tened properly, the MIL may come on.
• Use only a genuine NISSAN rubber tube as a replacement.
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0456
0456 Evaporative 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
Revision: April 20092010 QX56

P0456 EVAP CONTROL SYSTEMEC-263
< COMPONENT DIAGNOSIS > [VK56DE]
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1. Attach the EVAP service port
adapter (commercial service tool)
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 ON.
5. Connect GST and select Service $08.
6. Using Service $08, control the EVAP canister vent control valve (close).
7. Apply pressure and make sure the following conditions are sat- isfied.
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 dr opped more than 0.4 kPa (3
mmHg, 0.12 inHg).
If NG, go to EC-263, "
Diagnosis Procedure".
If OK, go to next step.
8. Disconnect GST.
9. Start engine and warm it up to normal operating temperature.
10. Turn ignition switch OFF and wait at least 10 seconds.
11. Restart engine and let it idle for 90 seconds.
12. Keep engine speed at 2,000 rpm for 30 seconds.
13. Turn ignition switch OFF. NOTE:
For more information, refer to GST Instruction Manual.
Diagnosis ProcedureINFOID:0000000005149284
1.CHECK FUEL FILLER CAP DESIGN
1. Turn ignition switch OFF.
2. Check for genuine NISSAN fuel filler cap design.
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 >> 1. Open fuel filler cap, then clean cap and fuel filler neck threads using air blower. 2. Retighten until ratcheting sound is heard.
BBIA0366E
SEF462UI
SEF915U
Revision: April 20092010 QX56

EC-264
< COMPONENT DIAGNOSIS >[VK56DE]
P0456 EVAP CONTROL SYSTEM
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
Refer to EC-268, "
Component Inspection".
OK or NG
OK >> GO TO 5.
NG >> Replace fuel filler cap with a genuine one.
5.INSTALL THE PRESSURE PUMP
To locate the EVAP leak, install EVAP service port adapter and pres-
sure pump to EVAP service port securely.
NOTE:
Improper installation of the EV AP service port adapter to the
EVAP service port may cause leaking.
With CONSULT-III>>GO TO 6.
Without CONSULT-III>>GO TO 7.
6.CHECK FOR EVAP LEAK
With CONSULT-III
1. Turn ignition switch ON.
2. Select “EVAP SYSTEM CLOSE” of “WORK SUPPORT” mode with CONSULT-III.
3. Touch “START” and apply pressure into the EVAP line until the pressure indicator reaches the middle of
the bar graph.
CAUTION:
• Do not use compressed air or a high pressure pump.
• Do not exceed 4.12 kPa (0.042 kg/cm
2, 0.6 psi) of pressure in the system.
BBIA0366E
SEF916U
Revision: April 20092010 QX56

P0456 EVAP CONTROL SYSTEMEC-267
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OK >> GO TO 15.
NG >> Repair or reconnect the hose.
15.CHECK EVAP CANISTER PURGE VOLUME CONTROL SOLENOID VALVE
Refer to EC-233, "
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-184, "
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-243, "
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-37, "
Description".
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.
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-412
.
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-414, "
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 MWI-33, "
Component Inspection".
OK or NG
OK >> GO TO 24.
Revision: April 20092010 QX56

EC-268
< COMPONENT DIAGNOSIS >[VK56DE]
P0456 EVAP CONTROL SYSTEM
NG >> Replace fuel level sensor unit.
24.CHECK INTERMITTENT INCIDENT
Refer to GI-35, "
How to Check Terminal" and GI-38, "Intermittent Incident".
>> INSPECTION END
Component InspectionINFOID:0000000005149285
FUEL TANK VACUUM RELIEF VALVE (BUILT INTO FUEL FILLER CAP)
1. Wipe clean valve housing.
2. Check valve opening pressure and vacuum.
3. If out of specification, replace fuel filler cap as an assembly.
CAUTION:
Use only a genuine fuel filler cap as a replacement. If an incor-
rect fuel filler cap is used, the MIL may come on.
SEF445Y
Pressure:
15.3 - 20.0 kPa (0.156 - 0.204 kg/cm2, 2.22 -
2.90 psi)
Vacuum: −6.0 to −3.3 kPa (− 0.061 to −0.034 kg/cm
2,
− 0.87 to −0.48 psi)
SEF943S
Revision: April 20092010 QX56