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Home >> Nissan-Datsun >> 2008 >> Sentra SE-R >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Engine Control System - DTCS P0447 To P0850 (Qr25DE) >> DTC P0451 EVAP Control System Pressure Sensor >> Diagnostic Procedure
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Diagnostic Procedure

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

      Refer to "GROUND INSPECTION ".

      Fig 1: Identifying Body Ground Connections
      G04926018Courtesy 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 (1) harness connector.
      • This illustration is a view from under vehicle
      • EVAP canister (2)
      • EVAP canister vent control valve (3)
    2. Check sensor harness connector for water.

      Water should not exist. 

      Fig 2: Identifying EVAP Control System Pressure Sensor, EVAP Canister And EVAP Canister Vent Control Valve
      G04925106Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    OK: GO TO 3.

    NG: Repair or replace harness connector.

  3. CHECK POWER SUPPLY CIRCUITS 

    Check harness for short to power and short to ground, between the following terminals.

    ECM TERMINAL REFERENCE

    ECM terminal Sensor terminal Reference Wiring Diagram
    72 Refrigerant pressure sensor terminal 3 "WIRING DIAGRAM "
    76 Crankshaft position sensor (POS) terminal 1 "WIRING DIAGRAM "
    87 APP sensor terminal 5 "WIRING DIAGRAM "
    91 EVAP control system pressure sensor terminal 3 "WIRING DIAGRAM "

    OK or NG 

    OK: GO TO 4.

    NG: Repair short to ground or short to power in harness or connectors.

  4. CHECK REFRIGERANT PRESSURE SENSOR 

    Refer to "TROUBLE DIAGNOSIS ".

    OK or NG 

    OK: GO TO 5.

    NG: Replace refrigerant pressure sensor.

  5. CHECK CRANKSHAFT POSITION SENSOR (POS) 

    Refer to "COMPONENT INSPECTION ".

    OK or NG 

    OK: GO TO 6.

    NG: Replace crankshaft position sensor (POS).

  6. CHECK APP SENSOR 

    Refer to "COMPONENT INSPECTION ".

    OK or NG 

    OK: GO TO  8.

    NG: GO TO 7.

  7. REPLACE ACCELERATOR PEDAL ASSEMBLY 
    1. Replace accelerator pedal assembly.
    2. Perform "ACCELERATOR PEDAL RELEASED POSITION LEARNING ".
    3. Perform "THROTTLE VALVE CLOSED POSITION LEARNING ".
    4. Perform "IDLE AIR VOLUME LEARNING ".

    : INSPECTION END 

  8. CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR 

    Refer to "COMPONENT INSPECTION ".

    OK or NG 

    OK: GO TO 9.

    NG: Replace EVAP control system pressure sensor.

  9. CHECK INTERMITTENT INCIDENT 

    Refer to "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT ".

    For wiring diagram, refer to "WIRING DIAGRAM ".

    : INSPECTION END