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Home >> Lexus >> 2024 >> RX 500h >> Repair and Diagnosis >> External Pages >> Different car >> Section 85 (Heating / Air Conditioning System - Diagnostic Codes (3 Of 3), Circuit Tests & Symptom Tests) >> AIR CONDITIONING SYSTEM (for PHEV Model) >> Recirculated/Fresh Air Modes do not Switch [08/2023 - ] >> Procedure

Recirculated/Fresh Air Modes do not Switch [08/2023 - ]: Procedure

WARNING: This page is about a different car, the 2025 Lexus RX 450h+ and 2024 Lexus RX 450h+. However, it is still accessible from the selected car via links, so may be relevant.
  1. CHECK NO. 5 AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLY 
    1. Check that the No. 5 air conditioning radiator damper servo sub-assembly is installed correctly.

      OK

      No. 5 air conditioning radiator damper servo sub-assembly is installed correctly.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REINSTALL NO. 5 AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLY. Refer to  REASSEMBLY [10/2022 - ] 

    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 [08/2023 - ] 

    Result: 

    GO TO DTC B143B-7F. Refer to  DTC B143B-7F: Air Inlet Damper Control Servo Motor Actuator Stuck Off [08/2023 - ] 

    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: 

    NG 

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

    Result: 

    OK 

    See step  4

  4. CONFIRM MODEL 

    Result

    Result Proceed to
    w/o Smog Ventilation Sensor A
    w/ Smog Ventilation Sensor B

    Result: 

    REPLACE AIR CONDITIONER UNIT ASSEMBLY. Refer to  REMOVAL [08/2023 - ] 

    Result: 

    See step  5

  5. INSPECT SMOG VENTILATION SENSOR 

    Refer to INSPECTION [10/2022 - ]

    Result

    Proceed to
    OK
    NG

    Result: 

    OK 

    REPLACE AIR CONDITIONER UNIT ASSEMBLY. Refer to  REMOVAL [08/2023 - ] 

    Result: 

    NG 

    REPLACE SMOG VENTILATION SENSOR. Refer to  REMOVAL [10/2022 - ]