LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Infiniti >> 2009 >> QX56 AWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - Component Testing >> On-Vehicle Maintenance >> EVAP Leak Check >> How to Detect Fuel Vapor Leakage
April 5, 2026: LEMON Manuals is launched! Read the announcement.

How to Detect Fuel Vapor Leakage

CAUTION:
  • 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 EVAP system.
NOTE:
  • Do not start engine.
  • Improper installation of EVAP service port adapter to the EVAP service port may cause a leak.

WITH CONSULT-III

  1. Attach the EVAP service port adapter securely to the EVAP service port.
  2. Also attach the pressure pump and hose to the EVAP service port adapter.
  3. Turn ignition switch ON.
  4. Select the "EVAP SYSTEM CLOSE" of "WORK SUPPORT MODE" with CONSULT-III.
  5. Touch "START". A bar graph (Pressure indicating display) will appear on the screen.
  6. Apply positive pressure to the EVAP system until the pressure indicator reaches the middle of the bar graph.
  7. Remove EVAP service port adapter and hose with pressure pump.
  8. Locate the leak using a leak detector. Refer to "DESCRIPTION ".
    Fig 1: Identifying EVAP Leak Detector
    G06315974Courtesy of NISSAN MOTOR CO., U.S.A.

WITHOUT CONSULT-III

  1. Attach the EVAP service port adapter securely to the EVAP service port.
    Fig 2: Identifying EVAP Service Port And EVAP Canister Purge Volume Control Solenoid Valve
    G06315975Courtesy of NISSAN MOTOR CO., U.S.A.
  2. Also attach the pressure pump with pressure gauge to the EVAP service port adapter.
    Fig 3: Identifying Pressure Pump Connection With EVAP Service Port Adapter
    G06315976Courtesy of NISSAN MOTOR CO., U.S.A.
  3. Apply battery voltage between the terminals of EVAP canister vent control valve to make a closed EVAP system.
    Fig 4: Identifying EVAP Canister Vent Control Valve And EVAP Control System Pressure Sensor
    G06315977Courtesy of NISSAN MOTOR CO., U.S.A.
  4. To locate the leak, deliver positive pressure to the EVAP system until pressure gauge points reach 1.38 to 2.76 kPa (0.014 to 0.028 kg/cm2 , 0.2 to 0.4 psi).
  5. Remove EVAP service port adapter and hose with pressure pump.
  6. Locate the leak using a leak detector. Refer to "DESCRIPTION ".