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Home >> Toyota >> 2021 >> Highlander LE, 4WD >> Repair and Diagnosis >> Heating, Ventilation & A/C (HVAC) >> HVAC Control Systems >> Heating / Air Conditioning System (Except HV, W/ Manual A/C) - Diagnostic Codes, Circuit Tests & Symptom Tests >> AIR CONDITIONING SYSTEM (for Gasoline Model with Manual Air Conditioning System) >> Recirculated/Fresh Air Modes Switch without User Input [12/2019 - 10/2022] >> Procedure

Recirculated/Fresh Air Modes Switch without User Input [12/2019 - 10/2022]: Procedure

  1. READ VALUE USING GTS (AMBIENT TEMP SENSOR) 
    1. Read the Data List according to the display on the GTS.

      Body Electrical > Air Conditioner > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Ambient Temp Sensor Ambient temp. sensor (thermistor assembly) Min.: -23.30°C (-9.94°F)
      Max.: 65.95°C (150.71°F)      		 Actual ambient temperature displayed Ambient temp. sensor (thermistor assembly) circuit malfunction
      • When open circuit: -23.30°C (-9.94°F)
      • When short circuit: 65.95°C (150.71°F)

      Body Electrical > Air Conditioner > Data List 

      Tester Display
      Ambient Temp Sensor

      OK

      The value of the display does not change frequently.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    GO TO OTHER DIAGNOSIS PROCEDURE (Ambient Temperature Display System). Refer to  Ambient Temperature Display System [12/2019 - 10/2022]  

    Result: 

    OK 

    See step  2

  2. READ VALUE USING GTS (COOLANT TEMPERATURE) 
    1. Read the Data List according to the display on the GTS.

      Powertrain > Engine > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Coolant Temperature Engine coolant temperature Min.: -40°C (-40°F)
      Max.: 140°C (284°F)      		 75 to 100°C (167 to 212°F): After warming up This is the engine coolant temperature.

      HINT: 

      • After warming up the engine, the engine coolant temperature will be 75 to 100°C (167 to 212°F).
      • After a long soak, the engine coolant temperature, intake air temperature and ambient air temperature will be approximately equal.
      • If the value is -40°C (-40°F), or higher than 135°C (275°F), the sensor circuit is open or shorted.
      • Check if the engine overheats if the value indicated is higher than 135°C (275°F).

      Powertrain > Engine > Data List 

      Tester Display
      Coolant Temperature

      OK

      The value of the display does not change frequently.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    GO TO COOLING SYSTEM. Refer to  ON-VEHICLE INSPECTION [12/2019 - 10/2022] 

    Result: 

    OK 

    See step  3

  3. CHECK REFRIGERANT PRESSURE 
    1. Install a manifold gauge set.

      Refer to ON-VEHICLE INSPECTION [12/2019 - ]

    2. Prepare the vehicle according to the table below.
      MEASUREMENT CONDITION:

      Item Condition
      Vehicle Condition Engine start
      Doors Fully closed (windows also fully closed)
      A/C Switch On
      Recirculation/fresh Control Switch Recirculation
      Set Temperature MAX COLD
      Blower Speed HI
      Air Conditioning Air Inlet Temperature 25 to 35°C (77 to 95°F)
    3. Read the manifold gauge pressure.

      Standard Pressure

      Low pressure side 

      150 to 250 kPa (1.5 to 2.5 kgf/cm2 , 22 to 36 psi)

      High pressure side 

      1370 to 1570 kPa (14 to 16 kgf/cm2 , 199 to 228 psi)

    4. Compare the values displayed in the Data List and on the manifold gauge.

      Body Electrical > Air Conditioner > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Regulator Pressure Sensor Air conditioner pressure sensor Min.: -456.68 kPaG (gauge)
      Max.: 3294.37 kPaG (gauge)      		 Actual refrigerant pressure displayed
      • Refrigerant line (gas leak etc.)
      • Air conditioner pressure sensor circuit malfunction

      Body Electrical > Air Conditioner > Data List 

      Tester Display
      Regulator Pressure Sensor

      OK

      The values displayed in the Data List and on the manifold gauge match.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    INSPECT REFRIGERANT PRESSURE WITH MANIFOLD GAUGE SET. Refer to  ON-VEHICLE INSPECTION [12/2019 - ] 

    Result: 

    NG 

    REPLACE AIR CONDITIONER PRESSURE SENSOR. Refer to  REMOVAL [12/2019 - 10/2022] 

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