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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) >> No Heating at All [12/2019 - 11/2023] >> Procedure

No Heating at All [12/2019 - 11/2023]: Procedure

  1. 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  2

  2. PERFORM ACTIVE TEST USING GTS (AIR MIX SERVO PULSE) 
    1. Perform the Active Test according to the display on the GTS.

      Body Electrical > Air Conditioner > Active Test 

      Tester Display Measurement Item Control Range Diagnostic Note
      Air Mix Servo Targ Pulse(D) No. 1 air conditioning radiator damper servo sub-assembly (driver side air mix) pulse Min.: 128
      Max.: 383      		 Operates between 165 to 257 pulses
      Air Mix Servo Targ Pulse(P) No. 1 air conditioning radiator damper servo sub-assembly (front passenger side air mix) pulse Min.: 128
      Max.: 383      		 Operates between 255 to 347 pulses
      Rear Air Mix Servo Targ Pulse Rear air mix damper servo sub-assembly pulse Min.: 128
      Max.: 383      		 Operates between 213 to 258 pulses

      Body Electrical > Air Conditioner > Active Test 

      Tester Display
      Air Mix Servo Targ Pulse(D)

      Body Electrical > Air Conditioner > Active Test 

      Tester Display
      Air Mix Servo Targ Pulse(P)

      Body Electrical > Air Conditioner > Active Test 

      Tester Display
      Rear Air Mix Servo Targ Pulse

      OK

      Damper servo motor is operated.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE HEATER RADIATOR UNIT SUB-ASSEMBLY 

    for Front Side: Refer to DISASSEMBLY [12/2019 - 10/2022] , or refer to DISASSEMBLY [10/2022 - 11/2023]

    for Rear Side: Refer to DISASSEMBLY [12/2019 - ]

    Result: 

    NG 

    GO TO DIAGNOSTIC TROUBLE CODE CHART (FOR SERVO MOTOR OF APPLICABLE ABNORMAL OPERATION). Refer to  DIAGNOSTIC TROUBLE CODE CHART [12/2019 - 10/2022]  , or refer to  DIAGNOSTIC TROUBLE CODE CHART [10/2022 - 11/2023] 

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