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Home >> Lexus >> 2024 >> RX 500h >> Repair and Diagnosis >> External Pages >> Different car >> Section 83 (Heating / Air Conditioning System - Diagnostic Codes (1 Of 3)) >> AIR CONDITIONING SYSTEM (for PHEV Model) >> DTC B143B-7F: Air Inlet Damper Control Servo Motor Actuator Stuck Off [08/2023 - ] >> Procedure

DTC B143B-7F: Air Inlet Damper Control Servo Motor Actuator Stuck Off [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 (INSTALLATION CONDITION) 
    1. Check that the No. 5 air conditioning radiator damper servo sub-assembly is installed correctly.

      HINT: 

      Refer to REASSEMBLY [10/2022 - ]

      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 NO. 5 AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLY (MOTOR, LINK, DAMPER) 
    1. Check for a wire harness caught between the links of the motors and dampers.

      OK

      No wire harnesses are caught between the links of the motors and dampers.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REMOVE PINCHED WIRE HARNESS 

    Result: 

    OK 

    See step  3

  3. PERFORM ACTIVE TEST USING GTS 
    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 Inlet Damper Control Servo Motor This test activates the air inlet damper control servo motor.
      (No. 5 air conditioning radiator damper servo sub-assembly)      		 128: Min
      384: Max      		 Operate with the ignition switch ON.

      Body Electrical > Air Conditioner > Data List 

      Tester Display Measurement Item Range Normal Condition Inspection Item
      Air Inlet Damper Control Servo Motor Actual Pulse No. 5 air conditioning radiator damper servo sub-assembly actual pulse 128 to 384
      • Fresh: 220 (pulse)
      • Recirculation: 256 (pulse)
      		 No. 5 air conditioning radiator damper servo sub-assembly circuit malfunction

      Body Electrical > Air Conditioner > Active Test 

      Active Test Display
      Air Inlet Damper Control Servo Motor
      Data List Display
      Air Inlet Damper Control Servo Motor Actual Pulse

      OK

      The value of the Data List changes in accordance with the operation of the Active Test.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  8

    Result: 

    OK 

    See step  4

  4. PERFORM ACTIVE TEST USING GTS 
    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 Inlet Damper Control Servo Motor This test activates the air inlet damper control servo motor.
      (No. 5 air conditioning radiator damper servo sub-assembly)      		 128: Min
      384: Max      		 Operate with the ignition switch ON.

      Body Electrical > Air Conditioner > Data List 

      Tester Display Measurement Item Range Normal Condition Inspection Item
      Air Inlet Damper Control Servo Motor Target Pulse No. 5 air conditioning radiator damper servo sub-assembly target pulse 128 to 384
      • Fresh: 220 (pulse)
      • Recirculation: 256 (pulse)
      		 No. 5 air conditioning radiator damper servo sub-assembly circuit malfunction
      Air Inlet Damper Control Servo Motor Actual Pulse No. 5 air conditioning radiator damper servo sub-assembly actual pulse 128 to 384
      • Fresh: 220 (pulse)
      • Recirculation: 256 (pulse)
      		 No. 5 air conditioning radiator damper servo sub-assembly circuit malfunction

      Body Electrical > Air Conditioner > Active Test 

      Active Test Display
      Air Inlet Damper Control Servo Motor
      Data List Display
      Air Inlet Damper Control Servo Motor Target Pulse
      Air Inlet Damper Control Servo Motor Actual Pulse

      OK

      The target pulse value of the Data List matches the actual pulse.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [10/2022 - ] 

    Result: 

    NG 

    See step  5

  5. INSPECT AIR CONDITIONING HARNESS ASSEMBLY 

    Pre-procedure1

    • Disconnect the A No. 1 air conditioning radiator damper servo sub-assembly connector.
    • Disconnect the B No. 5 air conditioning radiator damper servo sub-assembly connector.
    • Measure the resistance according to the value(s) in the table below.
      GTY1072103Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to No. 1 Air Conditioning Radiator Damper Servo Sub-assembly)      		 *b Front view of wire harness connector
      (to No. 5 Air Conditioning Radiator Damper Servo Sub-assembly)

      Standard Resistance

      Tester Connection Condition Specified Condition Result
      A-1 (M-) - B-5 (M-) Always Below 1 Ω Ω
      A-2 (M+) - B-4 (M+) Always Below 1 Ω Ω
      A-3 (STE2) - B-3 (STE2) Always Below 1 Ω Ω
      A-4 (STE1) - B-2 (STE1) Always Below 1 Ω Ω
      A-5 (GND) - B-1 (GND) Always Below 1 Ω Ω
      A-1 (M-) or B-5 (M-) - Other terminals and body ground Always 10 kΩ or higher kΩ
      A-2 (M+) or B-4 (M+) - Other terminals and body ground Always 10 kΩ or higher kΩ
      A-3 (STE2) or B-3 (STE2) - Other terminals and body ground Always 10 kΩ or higher kΩ
      A-4 (STE1) or B-2 (STE1) - Other terminals and body ground Always 10 kΩ or higher kΩ

      Result

      Proceed to
      OK
      NG

    Post-procedure1

    • None

    Result: 

    NG 

    REPLACE AIR CONDITIONING HARNESS ASSEMBLY. Refer to  DISASSEMBLY [10/2022 - ] 

    Result: 

    OK 

    See step  6

  6. REPLACE NO. 5 AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLY 

    HINT: 

    Refer to DISASSEMBLY [10/2022 - ]

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    See step  7

  7. PERFORM ACTIVE TEST USING GTS 
    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 Inlet Damper Control Servo Motor This test activates the air inlet damper control servo motor.
      (No. 5 air conditioning radiator damper servo sub-assembly)      		 128: Min
      384: Max      		 Operate with the ignition switch ON.

      Body Electrical > Air Conditioner > Data List 

      Tester Display Measurement Item Range Normal Condition Inspection Item
      Air Inlet Damper Control Servo Motor Actual Pulse No. 5 air conditioning radiator damper servo sub-assembly actual pulse 128 to 384
      • Fresh: 220 (pulse)
      • Recirculation: 256 (pulse)
      		 No. 5 air conditioning radiator damper servo sub-assembly circuit malfunction

      Body Electrical > Air Conditioner > Active Test 

      Active Test Display
      Air Inlet Damper Control Servo Motor
      Data List Display
      Air Inlet Damper Control Servo Motor Actual Pulse

      OK

      The value of the Data List changes in accordance with the operation of the Active Test.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    END 

    Result: 

    NG 

    REPLACE AIR CONDITIONING HARNESS ASSEMBLY. Refer to  DISASSEMBLY [10/2022 - ] 

  8. PERFORM ACTIVE TEST USING GTS 
    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
      Front Air Outlet Damper Control Servo Motor This test activates the front air outlet damper control servo motor.
      (No. 1 air conditioning radiator damper servo sub-assembly (front mode))      		 128: Min
      384: Max      		 Operate with the ignition switch ON.

      Body Electrical > Air Conditioner > Data List 

      Tester Display Measurement Item Range Normal Condition Inspection Item
      Front Air Outlet Damper Control Servo Motor Actual Pulse No. 1 air conditioning radiator damper servo sub-assembly (front mode) actual pulse 128 to 384
      • FACE: 256 (pulse)
      • B/L: 267 (pulse)
      • FOOT-A: 288 (pulse)
      • FOOT-R (F): 297 (pulse)
      • FOOT-D: 305 (pulse)
      • F/D-R: 320 (pulse)
      • D/F: 339 (pulse)
      • DEF: 348 (pulse)
      		 No. 1 air conditioning radiator damper servo sub-assembly (front mode) circuit malfunction

      Body Electrical > Air Conditioner > Active Test 

      Active Test Display
      Front Air Outlet Damper Control Servo Motor
      Data List Display
      Front Air Outlet Damper Control Servo Motor Actual Pulse

      OK

      The value of the Data List changes in accordance with the operation of the Active Test.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    See step  6

    Result: 

    NG 

    See step  9

  9. CHECK BLOWER ASSEMBLY (DAMPER) 

    Pre-procedure1

    • Operate the dampers by hand.

      OK

      The dampers are easily operated by hand.

      Result

      Proceed to
      OK
      NG

    Post-procedure1

    • None

    Result: 

    OK 

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY. Refer to  REMOVAL [10/2022 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE BLOWER ASSEMBLY. Refer to  REMOVAL [08/2023 - ] 

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