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Home >> Toyota >> 2021 >> Highlander LE, 4WD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 91 (Heating / Air Conditioning System (HV) - Diagnostic Codes (2 Of 3)) >> AIR CONDITIONING SYSTEM (for HV Model) >> DTC B144C-7F: Front Left Air Mix Damper Control Servo Motor Actuator Stuck Off [11/2023 - ] >> Procedure

DTC B144C-7F: Front Left Air Mix Damper Control Servo Motor Actuator Stuck Off [11/2023 - ]: Procedure

WARNING: This page is about a different variant/trim than selected.
  1. CHECK FOR DTC 
    1. Check for DTCs.

      Body Electrical > Air Conditioner > Trouble Codes 

      Result

      Result Proceed to
      B144C-7F is output A
      DTCs in conjunction with No. 1 air conditioning radiator damper servo sub-assembly are output at same time B

    Result: 

    B 

    REPLACE NO. 1 AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLY 

    Refer to DISASSEMBLY [10/2022 - ]

    Result: 

    A 

    See step  2

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

      HINT: 

      Refer to REASSEMBLY [10/2022 - ]

      OK

      No. 1 air conditioning radiator damper servo sub-assembly is installed correctly.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REINSTALL NO. 1 AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLY 

    Refer to REASSEMBLY [10/2022 - ]

    Result: 

    OK 

    See step  3

  3. CHECK NO. 1 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  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
      Front Left Air Mix Damper Control Servo Motor This test activates the front left air mix damper control servo motor.
      (No. 1 air conditioning radiator damper servo sub-assembly (front left side air mix))      		 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 Left Air Mix Damper Control Servo Motor Actual Pulse No. 1 air conditioning radiator damper servo sub-assembly (front left side air mix) actual pulse 128 to 384
      • MAX COLD: 257 (pulse)
      • MAX HOT: 165 (pulse)
      		 No. 1 air conditioning radiator damper servo sub-assembly (front left side air mix) circuit malfunction

      Body Electrical > Air Conditioner > Active Test 

      Active Test Display
      Front Left Air Mix Damper Control Servo Motor
      Data List Display
      Front Left 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  8

    Result: 

    OK 

    See step  5

  5. 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 Left Air Mix Damper Control Servo Motor This test activates the front left air mix damper control servo motor.
      (No. 1 air conditioning radiator damper servo sub-assembly (front left side air mix))      		 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 Left Air Mix Damper Control Servo Motor Target Pulse No. 1 air conditioning radiator damper servo sub-assembly (front left side air mix) target pulse 128 to 384
      • MAX COLD: 257 (pulse)
      • MAX HOT: 165 (pulse)
      		 No. 1 air conditioning radiator damper servo sub-assembly (front left side air mix) circuit malfunction
      Front Left Air Mix Damper Control Servo Motor Actual Pulse No. 1 air conditioning radiator damper servo sub-assembly (front left side air mix) actual pulse 128 to 384
      • MAX COLD: 257 (pulse)
      • MAX HOT: 165 (pulse)
      		 No. 1 air conditioning radiator damper servo sub-assembly (front left side air mix) circuit malfunction

      Body Electrical > Air Conditioner > Active Test 

      Active Test Display
      Front Left Air Mix Damper Control Servo Motor
      Data List Display
      Front Left Air Mix Damper Control Servo Motor Target Pulse
      Front Left 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  6

  6. REPLACE NO. 1 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
      Front Left Air Mix Damper Control Servo Motor This test activates the front left air mix damper control servo motor.
      (No. 1 air conditioning radiator damper servo sub-assembly (front left side air mix))      		 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 Left Air Mix Damper Control Servo Motor Actual Pulse No. 1 air conditioning radiator damper servo sub-assembly (front left side air mix) actual pulse 128 to 384
      • MAX COLD: 257 (pulse)
      • MAX HOT: 165 (pulse)
      		 No. 1 air conditioning radiator damper servo sub-assembly (front left side air mix) circuit malfunction

      Body Electrical > Air Conditioner > Active Test 

      Active Test Display
      Front Left Air Mix Damper Control Servo Motor
      Data List Display
      Front Left 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 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 AIR CONDITIONING RADIATOR ASSEMBLY (DAMPER) 

    Pre-procedure1

    1. Remove the No. 1 air conditioning radiator damper servo sub-assembly.

      HINT: 

      Refer to DISASSEMBLY [10/2022 - ]

      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 AIR CONDITIONING RADIATOR ASSEMBLY 

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