LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Infiniti >> 2008 >> QX56 RWD >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Engine Control System - DTCS P0327 To P1145 >> DTC P0451: EVAP Control System Pressure Sensor >> Diagnosis Procedure
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Diagnosis Procedure

  1. CHECK GROUND CONNECTIONS
    1. Turn ignition switch OFF.
    2. Loosen and retighten three ground screws on the body.

      Refer to "GROUND INSPECTION ".

      Fig 1: Identifying Body Ground Screw
      G05739537Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    OK: GO TO 2.

    NG: Repair or replace ground connections.

  2. CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR CONNECTOR FOR WATER
    1. Disconnect EVAP control system pressure sensor harness connector.
      Fig 2: Applying Battery Voltage Between Terminals Of EVAP Canister Vent Control Valve
      G05739538Courtesy of NISSAN MOTOR CO., U.S.A.
    2. Check sensor harness connector for water.

      Water should not exist. 

    OK or NG 

    OK: GO TO 3.

    NG: Repair or replace harness connector.

  3. CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR

    Refer to "COMPONENT INSPECTION ".

    OK or NG 

    OK: GO TO 4.

    NG: Replace EVAP control system pressure sensor.

  4. CHECK INTERMITTENT INCIDENT

    Refer to "HOW TO CHECK TERMINAL " and "INTERMITTENT INCIDENT ".

    For wiring diagram, refer to "DIAGNOSIS PROCEDURE ".

    INSPECTION END