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Home >> Nissan-Datsun >> 2004 >> Pathfinder LE, RWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System >> DTC P1456: EVAP Control System >> Diagnostic Procedure
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Diagnostic Procedure

  1. CHECK FUEL FILLER CAP DESIGN 
    1. Turn ignition switch "OFF".
    2. Check for genuine NISSAN fuel filler cap design.
      Fig 1: Checking Fuel Filler Cap Design
      G00781124Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    1. OK GO TO 2.
    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 

    1. OK GO TO 3.
    2. NG
      • Open fuel filler cap, then clean cap and fuel filler neck threads using air blower.
      • 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 

    1. OK GO TO  5 .
    2. NG GO TO 4.
  4. CHECK FUEL TANK VACUUM RELIEF VALVE 
    1. Wipe clean valve housing.
    2. Check valve opening pressure and vacuum.
      Fig 2: Checking Fuel Tank Vacuum Relief Valve (1 Of 2)
      G00781125Courtesy of NISSAN MOTOR CO., U.S.A.
      Fig 3: Checking Fuel Tank Vacuum Relief Valve (2 Of 2)
      G00781126Courtesy of NISSAN MOTOR CO., U.S.A.

      Pressure: 15.3 - 20.0 kPa (0.156 - 0.204 kg/cm 2 , 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) 

      CAUTION: Use only a genuine fuel filler cap as a replacement. If an incorrect fuel filler cap is used, the MIL may come on.

    OK or NG 

    1. OK GO TO 5.
    2. 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 pressure pump to EVAP service port securely.

    Fig 4: Identifying Brake Fluid Reservoir And EVAP Service Port
    G00781127Courtesy of NISSAN MOTOR CO., U.S.A.
    Fig 5: Installing EVAP Service Port Adapter And Pressure Pump To EVAP Service Port
    G00781128Courtesy of NISSAN MOTOR CO., U.S.A.
    NOTE: Improper installation of the EVAP service port adapter to the EVAP service port may cause leaking.
    1. With CONSULT-II GO TO 6.
    2. Without CONSULT-II GO TO  7 .
  6. CHECK FOR EVAP LEAK 

    With CONSULT-II 

    1. Turn ignition switch "ON".
    2. Select "EVAP SYSTEM CLOSE" of "WORK SUPPORT" mode with CONSULT-II.
    3. Touch "START" and apply pressure into the EVAP line until the pressure indicator reaches the middle of the bar graph.
      NOTE:
      • Never use compressed air or a high pressure pump.
      • Do not exceed 4.12 kPa (0.042 kg/cm2 , 0.6 psi) of pressure in the system.
      Fig 6: Checking EVAP Leak With CONSULT-II
      G00781129Courtesy of NISSAN MOTOR CO., U.S.A.
    4. Using EVAP leak detector, locate the EVAP leak. For the leak detector, refer to the instruction manual for more details. Refer to "EVAPORATIVE EMISSION LINE DRAWING  " .
      Fig 7: View Of Leak Detector
      G00781130Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    1. OK GO TO  8 .
    2. NG Repair or replace.
  7. CHECK FOR EVAP LEAK 

    Without CONSULT-II 

    1. Turn ignition switch "OFF".
    2. Apply 12 volts DC to EVAP canister vent control valve. The valve will close. (Continue to apply 12 volts until the end of test.)
      Fig 8: Checking EVAP Leak Without CONSULT II (1 Of 2)
      G00781131Courtesy of NISSAN MOTOR CO., U.S.A.
    3. Apply 12 volts DC to vacuum cut valve bypass valve. The valve will open. (Continue to apply 12V until the end of test.)

      When bracket bolt is removed 

      Fig 9: Checking EVAP Leak Without CONSULT II (2 Of 2)
      G00781132Courtesy of NISSAN MOTOR CO., U.S.A.
    4. Pressurize the EVAP line using pressure pump with 1.3 to 2.7 kPa (10 to 20 mmHg, 0.39 to 0.79 inHg), then remove pump and EVAP service port adapter.
      NOTE:
      • Never use compressed air or a high pressure pump.
      • Do not exceed 4.12 kPa (0.042 kg/cm2 , 0.6 psi) of pressure in the system.
    5. Using EVAP leak detector, locate the EVAP leak. For the leak detector, refer to the instruction manual for more details. Refer to "EVAPORATIVE EMISSION LINE DRAWING  " .
      Fig 10: View Of Leak Detector
      G00781133Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    1. OK GO TO 8.
    2. NG Repair or replace.
  8. CHECK 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 and are not clogged by blowing air into with , and then plugged.
      Fig 11: Checking Water Separator
      G00781134Courtesy of NISSAN MOTOR CO., U.S.A.
    5. In case of NG in items 2 - 4, replace the parts.
    NOTE:
    • Do not disassemble water separator.

    OK or NG 

    1. OK GO TO 9.
    2. NG Replace water separator.
  9. CHECK EVAP CANISTER VENT CONTROL VALVE, O-RING AND CIRCUIT 

    Refer to "DTC CONFIRMATION PROCEDURE  " .

    OK or NG 

    1. OK GO TO 10.
    2. NG Repair or replace EVAP canister vent control valve and O-ring or harness/connector.
  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?
      Fig 12: Checking EVAP Canister Saturation
      G00781135Courtesy of NISSAN MOTOR CO., U.S.A.

    Yes or No 

    1. Yes GO TO 11.
    2. No (With CONSULT-II) GO TO  13 .
    3. 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 

    1. OK (With CONSULT-II) GO TO 13.
    2. OK (Without CONSULT-II) GO TO  14 .
    3. 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
    1. 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.
      Fig 13: Checking EVAP Canister Purge Volume Control Solenoid Valve Operation With CONSULT-II
      G00781136Courtesy of NISSAN MOTOR CO., U.S.A.

    Vacuum should exist. 

    OK or NG 

    1. OK GO TO  16 .
    2. NG GO TO  15 .
  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.

      Vacuum should exist. 

    OK or NG 

    1. OK GO TO  17 .
    2. NG GO TO 15.
  15. CHECK VACUUM HOSE 

    Check vacuum hoses for clogging or disconnection. Refer to "VACUUM HOSE DRAWING  " .

    OK or NG 

    1. OK (With CONSULT-II) GO TO 16.
    2. OK (Without CONSULT-II) GO TO  17 .
    3. NG Repair or reconnect the hose.
  16. CHECK EVAP CANISTER PURGE VOLUME CONTROL SOLENOID VALVE 

    With CONSULT-II 

    1. Start engine.
    2. Perform "PURG VOL CONT/V" in "ACTIVE TEST' mode with CONSULT-II. Check that engine speed varies according to the valve opening.
      Fig 14: Checking EVAP Canister Purge Volume Control Solenoid Valve With CONSULT-II
      G00781137Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    1. OK GO TO  18 .
    2. NG GO TO 17.
  17. CHECK EVAP CANISTER PURGE VOLUME CONTROL SOLENOID VALVE 

    With CONSULT-II 

    Check air passage continuity of EVAP canister purge volume control solenoid valve under the following conditions.

    Fig 15: Identifying EVAP Canister Purge Volume Control Solenoid Valve And Electric Throttle Control Actuator
    G00781138Courtesy of NISSAN MOTOR CO., U.S.A.
    Fig 16: Checking EVAP Canister Purge Volume Control Solenoid Valve With CONSULT-II
    G00781139Courtesy of NISSAN MOTOR CO., U.S.A.

    Without CONSULT-II 

    Check air passage continuity of EVAP canister purge volume control solenoid valve under the following conditions.

    Fig 17: Identifying EVAP Canister Purge Volume Control Solenoid Valve And Electric Throttle Control Actuator
    G00781140Courtesy of NISSAN MOTOR CO., U.S.A.
    Fig 18: Checking EVAP Canister Purge Volume Control Solenoid Valve Without CONSULT-II
    G00781141Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    1. OK GO TO 18.
    2. NG Replace EVAP canister purge volume control solenoid valve.
  18. CHECK FUEL TANK TEMPERATURE SENSOR 
    1. Remove fuel level sensor unit.
    2. Check resistance between fuel level sensor unit terminals 1 and 2 by heating with hot water or heat gun as shown in the figure.
      Fig 19: Checking Fuel Tank Temperature Sensor
      G00781142Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    1. OK GO TO 19.
    2. NG Replace fuel level sensor unit.
  19. CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR 
    1. Remove EVAP control system pressure sensor with its harness connector connected.
      • Never apply force to the air hole protector of the sensor if equipped. 
        Fig 20: Identifying Air Hole Protector
        G00781143Courtesy of NISSAN MOTOR CO., U.S.A.
    2. Remove EVAP control system pressure sensor from EVAP canister.

      Do not reuse the O-ring, replace it with a new one. 

    3. Install a vacuum pump to EVAP control system pressure sensor.
    4. Turn ignition switch "ON" and check output voltage between ECM terminal 32 and ground under the following conditions.
      Fig 21: Checking Output Voltage Between ECM Terminal 32 And Ground
      G00781144Courtesy of NISSAN MOTOR CO., U.S.A.
      CAUTION:
      • Always calibrate the vacuum pump gauge when using it.
      • Do not apply below -93.3 kPa (-700 mmHg, -27.56 inHg) or pressure over 101.3 kPa (760 mmHg, 29.92 inHg).
      • Discard and EVAP control system pressure sensor which has been dropped from a height of more than 0.5 m (19.7 in) onto a hard surface such as a concrete floor; use a new one.

    OK or NG 

    1. OK GO TO 20.
    2. NG Replace EVAP control system pressure sensor.
  20. CHECK EVAP PURGE LINE 

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

    Refer to "EVAPORATIVE EMISSION SYSTEM  " .

    OK or NG 

    1. OK GO TO 21.
    2. NG Repair or reconnect the hose.
  21. CLEAN EVAP PURGE LINE 

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

    1. GO TO 22.
  22. 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 "EVAPORATIVE EMISSION LINE DRAWING  " .

    OK or NG 

    1. OK GO TO 23.
    2. NG Repair or replace hoses and tubes.
  23. CHECK SIGNAL LINE AND RECIRCULATION LINE 
    • Check signal line and recirculation line between filler neck tube and fuel tank for clogging, kink, cracks, looseness and improper connection.

    OK or NG 

    1. OK GO TO 24.
    2. NG Repair or replace hoses, tubes or filler neck tube.
  24. CHECK REFUELING CONTROL VALVE 
    1. Remove fuel filler cap.
    2. Check air continuity between hose ends A and B.

      Blow air into hose end B. Air should flow freely into the fuel tank.

    3. Blow air into hose end A and check that there is no leakage.
    4. Apply pressure to both hose ends A and B [20 kPa (150 mmHg, 5.91 inHg)] using a pressure pump and a suitable 3-way connector. Check that there is no leakage.
      Fig 22: Checking Refueling Control Valve
      G00781145Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    1. OK GO TO 25.
    2. NG Replace or refueling control valve with fuel tank.
  25. CHECK FUEL LEVEL SENSOR 

    Refer to "FUEL LEVEL SENSOR UNIT CHECK ".

    OK or NG 

    1. OK GO TO 26.
    2. NG Replace fuel level sensor unit.
  26. CHECK INTERMITTENT INCIDENT 

    Refer to "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT  " .

    1. INSPECTION END