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Home >> Lexus >> 2025 >> NX 350h >> Repair and Diagnosis >> External Pages >> Different car >> Section 71 (Heating / Air Conditioning System - Diagnostic Codes, Circuit Tests & Symptom Tests) >> AIR CONDITIONING SYSTEM (for Gasoline Model) >> Recirculated/Fresh Air Modes do not Switch [11/2021 - ] >> Procedure

Recirculated/Fresh Air Modes do not Switch [11/2021 - ]: Procedure

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  1. CHECK NO. 3 AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLY 
    1. Check that the No. 3 air conditioning radiator damper servo sub-assembly is installed correctly.

      OK

      No. 3 air conditioning radiator damper servo sub-assembly is installed correctly.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REINSTALL NO. 3 AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLY. Refer to  REASSEMBLY [11/2021 - ] 

    Result: 

    OK 

    See step  2

  2. CHECK FOR DTC 
    1. Check for DTCs.

      Body Electrical > Air Conditioner > Trouble Codes 

      Result

      Result Proceed to
      B143A-87 and B143B-7F are not output A
      B143A-87 is output B
      B143B-7F is output C

    Result: 

    GO TO DTC B143A-87. Refer to  DTC B143A-87: Lost Communication with Air Inlet Damper Control Servo Motor LIN Missing Message [11/2021 - ]  

    Result: 

    GO TO DTC B143B-7F. Refer to  DTC B143B-7F: Air Inlet Damper Control Servo Motor Actuator Stuck Off [11/2021 - ]  

    Result: 

    See step  3

  3. READ VALUE USING GTS 
    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: 

    OK 

    REPLACE AIR CONDITIONER UNIT ASSEMBLY. Refer to  REMOVAL [11/2021 - 03/2022]  , or refer to  REMOVAL [03/2022 - ] 

    Result: 

    NG 

    GO TO COOLING SYSTEM 

    for A25A-FKS: Refer to ON-VEHICLE INSPECTION [11/2021 - ]

    for T24A-FTS: Refer to ON-VEHICLE INSPECTION [11/2021 - ]