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Home >> Toyota >> 2021 >> Highlander LE, 4WD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 99 (Heating / Air Conditioning System (HV) - Diagnostics - Introduction (1 Of 2)) >> AIR CONDITIONING SYSTEM (for HV Model) >> How To Proceed With Troubleshooting [11/2023 - ] >> Procedure

How To Proceed With Troubleshooting [11/2023 - ]: Procedure

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  1. VEHICLE BROUGHT TO WORKSHOP 

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    See step  2

  2. CUSTOMER PROBLEM ANALYSIS 

    HINT: 

    • In troubleshooting, confirm that the problem symptoms have been accurately identified. Preconceptions should be discarded in order to make an accurate judgment. To clearly understand what the problem symptoms are, it is extremely important to ask the customer about the problem and the conditions at the time the malfunction occurred.
    • Gather as much information as possible for reference. Past problems that seem unrelated may also help in some cases.
    • The following 5 items are important points for problem analysis:
      What Vehicle model, system name
      When Date, time, occurrence frequency
      Where Road conditions
      Under what conditions? Driving conditions, weather conditions
      How did it happen? Problem symptoms

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    See step  3

  3. INSPECT AUXILIARY BATTERY VOLTAGE 
    1. Inspect the auxiliary battery voltage with the ignition switch off.

      Standard Voltage

      11 to 14 V

      If the auxiliary battery voltage is below 11 V, recharge or replace the auxiliary battery before proceeding to the next step.

    2. Check the fuses and relays.
    3. Check the connector connections and terminals to make sure that there are no abnormalities such as loose connections, deformation, etc.

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  4

  4. CHECK COMMUNICATION FUNCTION OF CAN COMMUNICATION SYSTEM* 
    1. Using the GTS, check for CAN communication system DTCs.

      Refer to HOW TO PROCEED WITH TROUBLESHOOTING [11/2023 - ]

      Result

      Result Proceed to
      CAN communication system DTCs are not output A
      CAN communication system DTCs are output B

    Result: 

    GO TO CAN COMMUNICATION SYSTEM. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [11/2023 - ] 

    Result: 

    See step  5

  5. CHECK FOR DTC* 
    1. Check for DTCs and note any codes that are output.

      Body Electrical > Air Conditioner > Trouble Codes 

    2. Clear the DTCs.

      Body Electrical > Air Conditioner > Clear DTCs 

    3. Recheck for DTCs. Based on the DTCs output above, try to force output of the air conditioning system DTC by simulating the operation indicated by the DTC.

      Body Electrical > Air Conditioner > Trouble Codes 

      Result

      Result Proceed to
      DTCs are not output A
      DTCs are output B

    Result: 

    GO TO DIAGNOSTIC TROUBLE CODE CHART. Refer to  DIAGNOSTIC TROUBLE CODE CHART [11/2023 - ] 

    Result: 

    See step  6

  6. CHECK AIR CONDITIONING CONTROL ASSEMBLY 
    1. Operate each switch on the air conditioning control assembly and check that the switches of the air conditioning system operate normally.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    GO TO PROBLEM SYMPTOMS TABLE. Refer to  PROBLEM SYMPTOMS TABLE [11/2023 - ]  

    Result: 

    OK 

    See step  7

  7. CHECK BLOWER CONTROL 
    1. Operate the blower switch on the air conditioning control assembly and check that the blower control operates normally.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    GO TO PROBLEM SYMPTOMS TABLE. Refer to  PROBLEM SYMPTOMS TABLE [11/2023 - ]  

    Result: 

    OK 

    See step  8

  8. CHECK AIR INLET CONTROL 
    1. Operate the recirculation/fresh switch on the air conditioning control assembly and check that the air inlet control operates normally.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    GO TO PROBLEM SYMPTOMS TABLE. Refer to  PROBLEM SYMPTOMS TABLE [11/2023 - ]  

    Result: 

    OK 

    See step  9

  9. CHECK AIR OUTLET CONTROL 
    1. Operate the air outlet mode switch on the air conditioning control assembly and check that the air outlet control operates normally.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    GO TO PROBLEM SYMPTOMS TABLE. Refer to  PROBLEM SYMPTOMS TABLE [11/2023 - ]  

    Result: 

    OK 

    See step  10

  10. CHECK COOLING FUNCTION 
    1. Operate the temperature adjustment switches on the air conditioning control assembly and check that cool air is blown from the registers.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    GO TO PROBLEM SYMPTOMS TABLE. Refer to  PROBLEM SYMPTOMS TABLE [11/2023 - ]  

    Result: 

    OK 

    See step  11

  11. CHECK HEATER FUNCTION 
    1. Operate the temperature adjustment switches on the air conditioning control assembly and check that warm air is blown from the air registers.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    GO TO PROBLEM SYMPTOMS TABLE. Refer to  PROBLEM SYMPTOMS TABLE [11/2023 - ]  

    Result: 

    OK 

    See step  12

  12. USE SIMULATION METHOD TO CHECK 

    Refer to HOW TO PROCEED WITH TROUBLESHOOTING [12/2019 - ]

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    See step  13

  13. CONFIRMATION TEST 

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    END