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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/ Auto A/C) - Circuit Tests & Symptom Tests >> AIR CONDITIONING SYSTEM (for Gasoline Model with Automatic Air Conditioning System) >> Recirculated/Fresh Air Modes Switch without User Input [12/2019 - 11/2023] >> Procedure

Recirculated/Fresh Air Modes Switch without User Input [12/2019 - 11/2023]: Procedure

  1. CONFIRM MODEL 

    Result

    Result Proceed to
    except USA and Canada A
    for USA and Canada B

    Result: 

    B 

    See step  3

    Result: 

    A 

    See step  2

  2. CHECK CUSTOMIZE SETTING 
    1. Using the GTS, check that the customize setting Air Inlet Mode is not set to "Automatic".

      Air Conditioner 

      Tester Display Description Default Setting ECU
      Air Inlet Mode Function to change the mode automatically to recirculation air mode when turning the A/C on to cool the cabin quickly Automatic 0:Automatic, 1:Manual Air conditioning amplifier assembly

      OK

      Air Inlet Mode is not set to "Automatic".

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    CUSTOMIZE SETTING (Set Air Inlet Mode to "Manual") 

    Result: 

    OK 

    See step  3

  3. 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 - 11/2023]  

    Result: 

    OK 

    See step  4

  4. 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]  , or refer to  ON-VEHICLE INSPECTION [10/2022 - ] 

    Result: 

    OK 

    See step  5

  5. 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]  , or refer to  REMOVAL [10/2022 - ] 

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