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Home >> Infiniti >> 2012 >> QX56 AWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - Component Testing (For MEXICO) >> Refrigerant Pressure Sensor >> Diagnosis Procedure
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Diagnosis Procedure

  1. CHECK REFRIGERANT PRESSURE SENSOR POWER SUPPLY CIRCUIT
    1. Disconnect refrigerant pressure sensor harness connector.
    2. Turn ignition switch ON.
    3. Check the voltage between refrigerant pressure sensor harness connector and ground.
      Refrigerant pressure sensor Ground Voltage (V)
      Connector Terminal
      E77 1 Ground Approx. 5

      Is the inspection result normal? 

      YES: GO TO  3.

      NO: GO TO 2.

  2. DETECT MALFUNCTIONING PART

    Check the following.

    • Harness for open or short between ECM and refrigerant pressure sensor
    • Loose or poor connection for each connector and harness

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

  3. CHECK REFRIGERANT PRESSURE SENSOR GROUND CIRCUIT FOR OPEN AND SHORT
    1. Turn ignition switch OFF.
    2. Disconnect ECM harness connector.
    3. Check the continuity between refrigerant pressure sensor harness connector and ECM harness connector.
      Refrigerant pressure sensor ECM Continuity
      Connector Terminal Connector Terminal
      E77 3 E80 150 Existed
    4. Also check harness for short to ground and short to power.

      Is the inspection result normal? 

      YES: GO TO  5.

      NO: GO TO 4.

  4. DETECT MALFUNCTIONING PART

    Check the following.

    • Harness for open or short between ECM and refrigerant pressure sensor
    • Loose or poor connection for each connector and harness

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

  5. CHECK REFRIGERANT PRESSURE SENSOR INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
    1. Check the continuity between refrigerant pressure sensor harness connector and ECM harness connector.
      Refrigerant pressure sensor ECM Continuity
      Connector Terminal Connector Terminal
      E77 2 E80 144 Existed
    2. Also check harness for short to ground and short to power.

      Is the inspection result normal? 

      YES: GO TO  7.

      NO: GO TO 6.

  6. DETECT MALFUNCTIONING PART

    Check the following.

    • Harness for open or short between ECM and refrigerant pressure sensor
    • Loose or poor connection for each connector and harness

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

  7. CHECK INTERMITTENT INCIDENT

    Refer to "INTERMITTENT INCIDENT ".

    Is the inspection result normal? 

    YES: Replace refrigerant pressure sensor. Refer to "REFRIGERANT PRESSURE SENSOR: REMOVAL AND INSTALLATION ".

    NO: Repair or replace malfunctioning part.

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