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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) - Diagnostic Codes (1 Of 2) >> AIR CONDITIONING SYSTEM (for Gasoline Model with Automatic Air Conditioning System) >> DTC B140C-7F: Rear Air Mix Damper Control Servo Motor Actuator Stuck Off [11/2023 - ] >> Procedure

DTC B140C-7F: Rear Air Mix Damper Control Servo Motor Actuator Stuck Off [11/2023 - ]: Procedure

  1. CHECK REAR AIR MIX DAMPER SERVO SUB-ASSEMBLY (INSTALLATION CONDITION) 
    1. Check that the rear air mix damper servo sub-assembly is installed correctly.

      HINT: 

      Refer to REASSEMBLY [12/2019 - ]

      OK

      rear air mix damper servo sub-assembly is installed correctly.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REINSTALL REAR AIR MIX DAMPER SERVO SUB-ASSEMBLY 

    Refer to REASSEMBLY [12/2019 - ]

    Result: 

    OK 

    See step  2

  2. CHECK REAR AIR MIX 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
      Rear Air Mix Damper Control Servo Motor This test activates the rear air mix damper control servo motor.
      (Rear air mix 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
      Rear Air Mix Damper Control Servo Motor Actual Pulse Rear air mix damper servo sub-assembly actual pulse 128 to 384
      • MAX COLD: 254 (pulse)
      • MAX HOT: 299 (pulse)
      		 Rear air mix damper servo sub-assembly circuit malfunction

      Body Electrical > Air Conditioner > Active Test 

      Active Test Display
      Rear Air Mix Damper Control Servo Motor
      Data List Display
      Rear Air Mix 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  7

    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
      Rear Air Mix Damper Control Servo Motor This test activates the rear air mix damper control servo motor.
      (Rear air mix 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
      Rear Air Mix Damper Control Servo Motor Target Pulse Rear air mix damper servo sub-assembly target pulse 128 to 384
      • MAX COLD: 254 (pulse)
      • MAX HOT: 299 (pulse)
      		 Rear air mix damper servo sub-assembly circuit malfunction
      Rear Air Mix Damper Control Servo Motor Actual Pulse Rear air mix damper servo sub-assembly actual pulse 128 to 384
      • MAX COLD: 254 (pulse)
      • MAX HOT: 299 (pulse)
      		 Rear air mix damper servo sub-assembly circuit malfunction

      Body Electrical > Air Conditioner > Active Test 

      Active Test Display
      Rear Air Mix Damper Control Servo Motor
      Data List Display
      Rear Air Mix Damper Control Servo Motor Target Pulse
      Rear Air Mix 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 [12/2019 - ]

    Result: 

    NG 

    See step  5

  5. REPLACE REAR AIR MIX DAMPER SERVO SUB-ASSEMBLY 

    HINT: 

    Refer to DISASSEMBLY [12/2019 - ]

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    See step  6

  6. 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
      Rear Air Mix Damper Control Servo Motor This test activates the rear air mix damper control servo motor.
      (Rear air mix 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
      Rear Air Mix Damper Control Servo Motor Actual Pulse Rear air mix damper servo sub-assembly actual pulse 128 to 384
      • MAX COLD: 254 (pulse)
      • MAX HOT: 299 (pulse)
      		 Rear air mix damper servo sub-assembly circuit malfunction

      Body Electrical > Air Conditioner > Active Test 

      Active Test Display
      Rear Air Mix Damper Control Servo Motor
      Data List Display
      Rear Air Mix 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 NO. 2 AIR CONDITIONING HARNESS ASSEMBLY 

    Refer to DISASSEMBLY [12/2019 - ]

  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
      Rear Air Outlet Damper Control Servo Motor This test activates the rear air outlet damper control servo motor.
      (Rear mode 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
      Rear Air Outlet Damper Control Servo Motor Actual Pulse Rear mode damper servo sub-assembly actual pulse 128 to 384
      • FACE: 276 (pulse)
      • B/L: 233 (pulse)
      • FOOT: 200 (pulse)
      		 Rear mode damper servo sub-assembly circuit malfunction

      Body Electrical > Air Conditioner > Active Test 

      Active Test Display
      Rear Air Outlet Damper Control Servo Motor
      Data List Display
      Rear 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  5

    Result: 

    NG 

    See step  8

  8. CHECK AIR CONDITIONING RADIATOR ASSEMBLY (DAMPER) 

    Pre-procedure1

    1. Remove the rear air mix damper servo sub-assembly.

      HINT: 

      Refer to DISASSEMBLY [12/2019 - ]

      Procedure1

    2. Operate the dampers by hand.

      OK

      The dampers are easily operated by hand.

      Result

      Proceed to
      OK
      NG

      Post-procedure1

    3. None

    Result: 

    OK 

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY 

    Refer to REMOVAL [11/2023 - ]

    Result: 

    NG 

    REPAIR OR REPLACE REAR COOLING UNIT ASSEMBLY 

    Refer to REMOVAL [10/2022 - ]

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