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Home >> Infiniti >> 2008 >> QX56 RWD >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Engine Control System - DTCS P0327 To P1145 >> DTC P0452: EVAP Control System Pressure Sensor >> Diagnosis Procedure
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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
      G05739543Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    OK: GO TO 2.

    NG: Repair or replace ground connections.

  2. CHECK CONNECTOR
    1. Disconnect EVAP control system pressure sensor harness connector.
      Fig 2: Applying Battery Voltage Between Terminals Of EVAP Canister Vent Control Valve
      G05739544Courtesy 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 POWER SUPPLY CIRCUIT
    1. Turn ignition switch ON.
    2. Check voltage between EVAP control system pressure sensor terminal 3 and ground with CONSULT-III or tester.

      Voltage: Approximately 5V 

    OK or NG 

    OK: GO TO  5.

    NG: GO TO 4.

    Fig 3: Checking Voltage Between Ignition Coil Terminal 3 And Ground
    G05739545Courtesy of NISSAN MOTOR CO., U.S.A.
  4. DETECT MALFUNCTIONING PART

    Check the following.

    • Harness connectors C1, E41
    • Harness connectors E5, F14
    • Harness for open or short between EVAP control system pressure sensor and ECM

    Repair open circuit or short to ground or short to power in harness or connectors.

  5. CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR GROUND CIRCUIT FOR OPEN AND SHORT
    1. Turn ignition switch OFF.
    2. Disconnect ECM harness connector.
    3. Check harness continuity between EVAP control system pressure sensor terminal 1 and ECM terminal 67.

      Refer to WIRING DIAGRAM .

      Continuity should exist. 

    4. Also check harness for short to ground and short to power.

    OK or NG 

    OK: GO TO  7.

    NG: GO TO 6.

  6. DETECT MALFUNCTIONING PART

    Check the following.

    • Harness connectors C1, E41
    • Harness connectors E5, F14
    • Harness for open or short between EVAP control system pressure sensor and ECM

    Repair open circuit or short to ground or short to power in harness or connectors.

  7. CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
    1. Check harness continuity between ECM terminal 32 and EVAP control system pressure sensor terminal 2.

      Refer to WIRING DIAGRAM .

      Continuity should exist. 

    2. Also check harness for short to ground and short to power.

    OK or NG 

    OK: GO TO  9.

    NG: GO TO 8.

  8. DETECT MALFUNCTIONING PART

    Check the following.

    • Harness connectors C1, E41
    • Harness connectors E5, F14
    • Harness for open or short between EVAP control system pressure sensor and ECM

    Repair open circuit or short to ground or short to power in harness or connectors.

  9. CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR

    Refer to "COMPONENT INSPECTION ".

    OK or NG 

    OK: GO TO 10.

    NG: Replace EVAP control system pressure sensor.

  10. CHECK INTERMITTENT INCIDENT

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

    INSPECTION END 

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