Infiniti Q45. Manual - part 478

DTC P1442 EVAP CONTROL SYSTEM

EC-551

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10. 

CHECK IF EVAP CANISTER SATURATED WITH WATER

1.

Remove EVAP canister with EVAP canister vent control valve attached.

2.

Does water drain from the EVAP canister?

Yes or No

Yes

>> GO TO 11.

No (With CONSULT-II)>>GO TO 13.
No (Without CONSULT-II)>>GO TO 14.

11. 

CHECK EVAP CANISTER

Weigh the EVAP canister with the EVAP canister vent control valve attached.
The weight should be less than 1.8 kg (4.0 lb).

OK or NG

OK (With CONSULT-II)>>GO TO 13.
OK (Without CONSULT-II)>>GO TO 14.
NG

>> GO TO 12.

12. 

DETECT MALFUNCTIONING PART

Check the following.

●

EVAP canister for damage

●

EVAP hose between EVAP canister and water separator for clogging or poor connection

>> Repair hose or replace EVAP canister.

13. 

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 16.

NG

>> GO TO 15.

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Vacuum should exist.

PBIB1678E

EC-552

DTC P1442 EVAP CONTROL SYSTEM

14. 

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 17.

NG

>> GO TO 15.

15. 

CHECK VACUUM HOSE

Check vacuum hoses for clogging or disconnection. Refer to 

EC-102, "Vacuum Hose Drawing"

 .

OK or NG

OK

>> GO TO 16.

NG

>> Repair or reconnect the hose.

16. 

CHECK EVAP CANISTER PURGE VOLUME CONTROL SOLENOID VALVE

Refer to 

EC-411, "Component Inspection"

 .

OK or NG

OK

>> GO TO 17.

NG

>> Replace EVAP canister purge volume control solenoid valve.

17. 

CHECK FUEL TANK TEMPERATURE SENSOR

Refer to 

EC-347, "Component Inspection"

 .

OK or NG

OK

>> GO TO 18.

NG

>> Replace fuel level sensor unit.

18. 

CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR

Refer to 

EC-450, "Component Inspection"

 .

OK or NG

OK

>> GO TO 19.

NG

>> Replace EVAP control system pressure sensor.

19. 

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 20.

NG

>> Repair or reconnect the hose.

20. 

CLEAN EVAP PURGE LINE

Clean EVAP purge line (pipe and rubber tube) using air blower.

>> GO TO 21.

Vacuum should exist.

DTC P1442 EVAP CONTROL SYSTEM

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21. 

CHECK REFUELING EVAP VAPOR LINE

Check refueling EVAP vapor line between EVAP canister and fuel tank for clogging, kink, looseness and
improper connection. For location, refer to 

EC-38, "ON BOARD REFUELING VAPOR RECOVERY (ORVR)"

 .

OK or NG

OK

>> GO TO 22.

NG

>> Repair or replace hoses and tubes.

22. 

CHECK SIGNAL LINE AND RECIRCULATION LINE

Check signal line and recirculation line between filler neck tube and fuel tank for clogging, kink, cracks, loose-
ness and improper connection.

OK or NG

OK

>> GO TO 23.

NG

>> Repair or replace hoses, tubes or filler neck tube.

23. 

CHECK REFUELING CONTROL VALVE

Refer to 

EC-41, "Component Inspection"

 .

OK or NG

OK

>> GO TO 24.

NG

>> Replace refueling control valve with fuel tank. 

24. 

CHECK FUEL LEVEL SENSOR

Refer to 

DI-22, "CHECK FUEL LEVEL SENSOR UNIT"

 .

OK or NG

OK

>> GO TO 25.

NG

>> Replace fuel level sensor unit.

25. 

CHECK INTERMITTENT INCIDENT

Refer to 

EC-145, "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT"

 .

>> INSPECTION END

Component Inspection

NBS0022N

WATER SEPARATOR

1.

Check visually for insect nests in the water separator air inlet.

2.

Check visually for cracks or flaws in the appearance.

3.

Check visually for cracks or flaws in the hose.

4.

Check that A  and C  are not clogged by blowing air into B  with
A , and then C  plugged.

5.

In case of NG in items 2 - 4, replace the parts.

NOTE:

●

Do not disassemble water separator.

PBIB1032E

EC-554

DTC P1456 EVAP CONTROL SYSTEM

DTC P1456 EVAP CONTROL SYSTEM

PFP:14710

On Board Diagnosis Logic

NBS0023B

NOTE:
If DTC P1456 is displayed with P1442, perform TROUBLE DIAGNOSIS FOR DTC P1456 first.
This diagnosis detects very small leaks in the EVAP line between fuel tank and EVAP canister purge volume
control solenoid valve, using vapor pressure in the fuel tank 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 P1442 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
0456

Evaporative emission 
control system very 
small leak (negative 
pressure check)

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EVAP system has a very small leak.

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EVAP system does not operate prop-
erly.

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Incorrect fuel tank vacuum relief valve

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Incorrect fuel filler cap used

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Fuel filler cap remains open or fails to close.

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Foreign matter caught in fuel filler cap.

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

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

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EVAP canister or fuel tank leaks

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EVAP purge line (pipe and rubber tube) leaks

●

EVAP purge line rubber tube bent

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Blocked or bent rubber tube to EVAP control sys-
tem pressure sensor

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Loose or disconnected rubber tube

●

EVAP canister vent control valve and the circuit

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EVAP canister purge volume control solenoid 
valve and the circuit

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Absolute pressure sensor

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Fuel tank temperature sensor

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

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Water separator

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EVAP canister is saturated with water

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EVAP control system pressure sensor

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Refueling control valve

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ORVR system leaks

●

Fuel level sensor and the circuit

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

SEF323U