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Home >> Infiniti >> 2005 >> QX56 AWD >> Repair and Diagnosis >> Engine Performance >> Engine Control System >> Refrigerant Pressure Sensor >> Diagnostic Procedure
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Diagnostic Procedure

  1. CHECK REFRIGERANT PRESSURE SENSOR OVERALL FUNCTION 
    1. Start engine and warm it up to normal operating temperature.
    2. Turn A/C switch and blower switch ON.
    3. Check voltage between ECM terminal 70 and ground with CONSULT-II or tester.
      Fig 1: Checking Refrigerant Pressure Sensor Overall Function
      G02389434Courtesy of NISSAN MOTOR CO., U.S.A.
      1. Voltage: 1.0-4.0V 

    OK or NG 

    1. OK: INSPECTION END
    2. NG: GO TO 2.
  2. CHECK GROUND CONNECTIONS 
    1. Turn A/C switch and blower switch OFF.
    2. Turn ignition switch OFF.
    3. Loosen and retighten three ground screws on the body. Refer to "GROUND INSPECTION ".
      Fig 2: Checking Ground Connections
      G02389435Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    1. OK: GO TO 3.
    2. NG: Repair or replace ground connections.
  3. CHECK REFRIGERANT PRESSURE SENSOR POWER SUPPLY CIRCUIT 
    1. Disconnect refrigerant pressure sensor harness connector.
    2. Turn ignition switch ON.
      Fig 3: Disconnecting Refrigerant Pressure Sensor Harness Connector
      G02389436Courtesy of NISSAN MOTOR CO., U.S.A.
    3. Check voltage between refrigerant pressure sensor terminal 1 and ground with CONSULT-II or tester.
      1. Voltage: Approximately 5V 

    OK or NG 

    1. OK: GO TO  5.
    2. NG: GO TO 4.
    Fig 4: Checking Voltage Between Refrigerant Pressure Sensor Terminal 1 And Ground
    G02389437Courtesy of NISSAN MOTOR CO., U.S.A.
  4. DETECT MALFUNCTIONING PART 

    Check the following.

    • Harness connectors E5, F14
    • Harness for open or short between ECM and refrigerant pressure sensor
      1. Repair harness or connectors.
  5. CHECK REFRIGERANT PRESSURE SENSOR GROUND CIRCUIT FOR OPEN AND SHORT 
    1. Turn ignition switch OFF.
    2. Disconnect ECM harness connector.
    3. Check harness continuity between refrigerant pressure sensor terminal 3 and ECM terminal 67. Refer to WIRING DIAGRAM .
      1. Continuity should exist. 
    4. Also check harness for short to ground and short to power.

    OK or NG 

    1. OK: GO TO  7.
    2. NG: GO TO 6.
  6. DETECT MALFUNCTIONING PART 

    Check the following.

    • Harness connectors E5, F14
    • Harness for open or short between ECM and refrigerant pressure sensor
      1. Repair open circuit or short to ground or short to power in harness or connectors.
  7. CHECK REFRIGERANT PRESSURE SENSOR INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT 
    1. Check harness continuity between ECM terminal 70 and refrigerant pressure sensor terminal 2. Refer to WIRING DIAGRAM .
      1. Continuity should exist. 
    2. Also check harness for short to ground and short to power.

    OK or NG 

    1. OK: GO TO  9.
    2. NG: GO TO 8.
  8. DETECT MALFUNCTIONING PART 

    Check the following.

    • Harness connectors E5, F14
    • Harness for open or short between ECM and refrigerant pressure sensor
      1. Repair open circuit or short to ground or short to power in harness or connectors.
  9. CHECK INTERMITTENT INCIDENT 

    Refer to "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT ".

    OK or NG 

    1. OK: Replace refrigerant pressure sensor.
    2. NG: Repair or replace.
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