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Home >> Infiniti >> 2017 >> QX80 Base, RWD >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Engine Control System (DTCS) (2 Of 4) >> DTC/Circuit Diagnosis >> DTC P0456: EVAP Control System >> Diagnosis Procedure >> Diagnostic Test
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Diagnostic Test

  1. CHECK FUEL FILLER CAP DESIGN

    1. Turn ignition switch OFF.
    2. Check for genuine NISSAN fuel filler cap design.
      G04074945Courtesy of NISSAN NORTH AMERICA, INC.

    Is the inspection result normal?

    YES 

    GO TO STEP 2  .

    NO 

    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.

    Is the inspection result normal?

    YES 

    GO TO STEP 3  .

    NO 

    Open fuel filler cap, then clean cap and fuel filler neck threads using air blower. Then retighten until reteaching sound is heard.

  3. CHECK FUEL FILLER CAP FUNCTION

    Check for air releasing sound while opening the fuel filler cap.

    Is the inspection result normal?

    YES 

    GO TO STEP 5  .

    NO 

    GO TO STEP 4  .

  4. CHECK FUEL TANK VACUUM RELIEF VALVE

    Refer to COMPONENT INSPECTION (FUEL FILLER CAP) .

    Is the inspection result normal?

    YES 

    GO TO STEP 5  .

    NO 

    Replace fuel filler cap with a genuine one.

  5. CHECK FOR EVAP LEAK

    Refer to INSPECTION .

    Is there any leak in EVAP line?

    YES 

    Repair or replace.

    NO 

    GO TO STEP 6  .

  6. CHECK EVAP CANISTER VENT CONTROL VALVE

    Check the following.

    Is the inspection result normal?

    YES 

    GO TO STEP 7  .

    NO 

    Repair or replace EVAP canister vent control valve and O-ring. Refer to EXPLODED VIEW WITH TORQUE SPECIFICATIONS .

  7. CHECK IF EVAP CANISTER SATURATED WITH WATER

    1. Remove EVAP canister (1) with EVAP canister vent control valve (2) and EVAP control system pressure sensor attached.
      G07026343Courtesy of NISSAN NORTH AMERICA, INC.
    2. Check if water will drain from the EVAP canister.

    Does water drain from EVAP canister?

    YES 

    GO TO STEP 8  .

    NO-1 

    With CONSULT: GO TO STEP  10.

    NO-2 

    Without CONSULT: GO TO STEP  11.

  8. CHECK EVAP CANISTER

    Weigh the EVAP canister assembly with the EVAP canister vent control valve and EVAP control system pressure sensor attached. Refer to EXPLODED VIEW WITH TORQUE SPECIFICATIONS .

    The weight should be less than 2.5 kg (5.5 lb). 

    Is the inspection result normal?

    YES-1 

    With CONSULT: GO TO STEP 10  .

    YES-2 

    Without CONSULT: GO TO STEP  11.

    NO 

    GO TO STEP 9  .

  9. 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. Refer to HYDRAULIC LAYOUT .

  10. CHECK EVAP CANISTER PURGE VOLUME CONTROL SOLENOID VALVE OPERATION

    G-20 WITH CONSULT

    1. Disconnect vacuum hose to EVAP canister purge volume control solenoid valve at EVAP service port.
    2. Start engine and let it idle.
    3. Select "PURG VOL CONT/V" in "ACTIVE TEST" mode.
    4. Touch "Qu" on CONSULT screen to increase "PURG VOL CONT/V" opening to 100%.
    5. Check vacuum hose for vacuum.
      Vacuum should exist.

    Is the inspection result normal?

    YES 

    GO TO STEP  13.

    NO 

    GO TO STEP 12  .

  11. CHECK EVAP CANISTER PURGE VOLUME CONTROL SOLENOID VALVE OPERATION

    G-21 WITHOUT CONSULT

    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.
      Vacuum should exist.

    Is the inspection result normal?

    YES 

    GO TO STEP 13  .

    NO 

    GO TO STEP 12  .

  12. CHECK VACUUM HOSE

    Check vacuum hoses for clogging or disconnection. Refer to HYDRAULIC LAYOUT .

    Is the inspection result normal?

    YES 

    GO TO STEP 13  .

    NO 

    Repair or reconnect the hose.

  13. CHECK EVAP CANISTER PURGE VOLUME CONTROL SOLENOID VALVE

    Refer to COMPONENT INSPECTION (EVAP CANISTER PURGE VOLUME CONTROL SOLENOID VALVE) .

    Is the inspection result normal?

    YES 

    GO TO STEP 14  .

    NO 

    Replace EVAP canister purge volume control solenoid valve. Refer to EXPLODED VIEW WITH TORQUE SPECIFICATIONS .

  14. CHECK FUEL TANK TEMPERATURE SENSOR

    Refer to COMPONENT INSPECTION .

    Is the inspection result normal?

    YES 

    GO TO STEP 15  .

    NO 

    Replace fuel level sensor unit. Refer to REMOVAL AND INSTALLATION .

  15. CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR

    Refer to COMPONENT INSPECTION (EVAP CONTROL SYSTEM PRESSURE SENSOR) .

    Is the inspection result normal?

    YES 

    GO TO STEP 16  .

    NO 

    Replace EVAP control system pressure sensor. Refer to COMPONENT INSPECTION (EVAP CONTROL SYSTEM PRESSURE SENSOR) .

  16. CHECK EVAP PURGE LINE

    Check EVAP purge line (pipe, rubber tube, fuel tank and EVAP canister) for cracks or improper connection.

    Refer to HYDRAULIC LAYOUT .

    Is the inspection result normal?

    YES 

    GO TO STEP 17  .

    NO 

    Repair or reconnect the hose.

  17. CLEAN EVAP PURGE LINE

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

    GO TO STEP 18  .

  18. CHECK EVAP/ORVR LINE

    Check EVAP/ORVR line between EVAP canister and fuel tank for clogging, kink, looseness and improper connection. For location, refer to HYDRAULIC LAYOUT .

    Is the inspection result normal?

    YES 

    GO TO STEP 19  .

    NO 

    Repair or replace hoses and tubes.

  19. CHECK RECIRCULATION LINE

    Check recirculation line between fuel filler tube and fuel tank for clogging, kink, cracks, looseness and improper connection.

    Is the inspection result normal?

    YES 

    GO TO STEP 20  .

    NO 

    Repair or replace hose, tube or fuel filler tube. Refer to EXPLODED VIEW WITH TORQUE SPECIFICATIONS .

  20. CHECK REFUELING EVAP VAPOR CUT VALVE

    Refer to COMPONENT INSPECTION (EVAP VAPOR CUT VALVE) .

    Is the inspection result normal?

    YES 

    GO TO STEP 21  .

    NO 

    Replace refueling EVAP vapor cut valve with fuel tank. Refer to EXPLODED VIEW WITH TORQUE SPECIFICATIONS .

  21. CHECK FUEL LEVEL SENSOR

    Refer to COMPONENT INSPECTION .

    Is the inspection result normal?

    YES 

    GO TO STEP 22  .

    NO 

    Replace fuel level sensor unit. Refer to REMOVAL AND INSTALLATION .

  22. CHECK INTERMITTENT INCIDENT

    Refer to INTERMITTENT INCIDENT .

    INSPECTION END

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