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Home >> Nissan-Datsun >> 2012 >> Sentra SE-R >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - DTCS P0171 To P0507 (Qr25DE) >> DTC P0451: 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 ground screws on the body.

    Refer to "GROUND INSPECTION ".

    Fig 1: Identifying Body Ground (E9 And E15) And Washer Tank With Fuse And Fusible Link Box
    G08185322Courtesy of NISSAN NORTH AMERICA, INC.

    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 that water is not inside connectors.
    Fig 2: Identifying EVAP Control System Pressure Sensor, EVAP Canister And EVAP Canister Vent Control Valve
    G04925106Courtesy of NISSAN NORTH AMERICA, INC.

    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 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. Refer to , "REMOVAL AND INSTALLATION FOR 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). Refer to , "DISASSEMBLY AND ASSEMBLY ".

  6. CHECK APP SENSOR

    Refer to "COMPONENT INSPECTION ".

    OK or NG 

    OK: GO TO  8.

    NG: GO TO 7.

  7. REPLACE ACCELERATOR PEDAL ASSEMBLY

    Replace accelerator pedal assembly. Refer to , "REMOVAL AND INSTALLATION ".

    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. Refer to , "REMOVAL AND INSTALLATION ".

  9. CHECK INTERMITTENT INCIDENT

    Refer to TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT .

    For wiring diagram, refer to "WIRING DIAGRAM ".

    INSPECTION END