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Home >> Toyota >> 2021 >> Highlander LE, 4WD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 100 (Cooling Fan System (A25A-FXS) - Diagnostics & Circuit Tests) >> Cooling Fan System >> Cooling Fan Circuit [12/2019 - 11/2023] >> Procedure

Cooling Fan Circuit [12/2019 - 11/2023]: Procedure

WARNING: This page is about a different variant/trim than selected.
  1. PERFORM ACTIVE TEST USING GTS (CONTROL THE ENGINE COOLING FAN DUTY RATIO) 
    1. Check the operation of the cooling fan while operating it using the GTS.

      Powertrain > Engine > Active Test 

      Tester Display
      Control the Engine Cooling Fan Duty Ratio

      OK

      GTS Operation Fan Operation
      30 - 100% Cooling fan operates
      0% Cooling fan stops

      Result

      Result Proceed to
      OK A
      Cooling fan does not operate B
      Cooling fan does not stop C

    Result: 

    A 

    PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to  PROBLEM SYMPTOMS TABLE [12/2019 - ]  

    Result: 

    C 

    See step  8

    Result: 

    B 

    See step  2

  2. CHECK HARNESS AND CONNECTOR (FAN WITH MOTOR ASSEMBLY - ECM) 
    1. Disconnect the A30 fan with motor assembly connector.
    2. Disconnect the A27 ECM connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A30-2 (SI) or A27-32 (RFC) - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR (FAN WITH MOTOR ASSEMBLY - ECM) 

    Result: 

    OK 

    See step  3

  3. INSPECT ECM (RFC TERMINAL) 
    1. Disconnect the A30 fan with motor assembly connector.
    2. Operate the cooling fan motor (fan with motor assembly) using the Active Test function and measure the resistance according to the value(s) in the table below.

      Powertrain > Engine > Active Test 

      Tester Display
      Control the Engine Cooling Fan Duty Ratio

      Standard Resistance

      Tester Connection GTS Operation Specified Condition
      A30-2 (SI) - Body ground Before Active Test (0%) → During Active Test (100%) Before Active Test (0%): Resistance is stable → During Active Test (100%): Resistance fluctuates*

      HINT: 

      *: Using the Active Test, duty control of the transistors in the ECM will be performed. Due to the duty control, resistance of the RFC terminal will be unstable during the Active Test. If the resistance is stable before the Active Test and fluctuates while performing the Active Test, it can be determined that the transistor is operating. If the transistor does not operate during the Active Test, the ECM may be malfunctioning.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE ECM. Refer to  REMOVAL [12/2019 - 10/2022]  , or refer to  REMOVAL [10/2022 - 11/2023] 

    Result: 

    OK 

    See step  4

  4. CHECK HARNESS AND CONNECTOR (FAN WITH MOTOR ASSEMBLY POWER SOURCE) 
    1. Disconnect the A29 fan with motor assembly connector.
      GTY911933Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Fan with Motor Assembly)
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      A29-2 (+B1) - A29-1 (E1) Always 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  7

    Result: 

    OK 

    See step  5

  5. CHECK HARNESS AND CONNECTOR (FAN WITH MOTOR ASSEMBLY POWER SOURCE) 
    1. Disconnect the A30 fan with motor assembly connector.
    2. Turn the ignition switch to ON.
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      A30-1 (IGS1) - Body ground Ignition switch ON 11 to 14 V
      GTY885597Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Fan with Motor Assembly)

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE FAN WITH MOTOR ASSEMBLY. Refer to  REMOVAL [12/2019 - 10/2021]  , or refer to  REMOVAL [10/2021 - ] 

    Result: 

    NG 

    See step  6

  6. CHECK HARNESS AND CONNECTOR (FAN WITH MOTOR ASSEMBLY - EFI-MAIN NO. 1 RELAY) 
    1. Disconnect the A30 fan with motor assembly connector.
    2. Remove the EFI-MAIN NO. 1 relay from the No. 1 engine room relay block and No. 1 junction block assembly.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A30-1 (IGS1) - 5 (EFI-MAIN NO. 1 relay) Always Below 1 Ω

      Result

      Result
      OK
      NG

    Result: 

    OK 

    CHECK ECM POWER SOURCE CIRCUIT. Refer to  ECM Power Source Circuit [12/2019 - 11/2023] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR (FAN WITH MOTOR ASSEMBLY - EFI-MAIN NO. 1 RELAY) 

  7. CHECK HARNESS AND CONNECTOR (FAN WITH MOTOR ASSEMBLY - BODY GROUND) 
    1. Disconnect the A29 fan with motor assembly connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A29-1 (E1) - Body ground Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPAIR OR REPLACE HARNESS OR CONNECTOR (FAN WITH MOTOR ASSEMBLY - BATTERY) 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR (FAN WITH MOTOR ASSEMBLY - BODY GROUND) 

  8. INSPECT ECM (RFC TERMINAL) 
    1. Disconnect the A30 fan with motor assembly connector.
    2. Operate the cooling fan motor (fan with motor assembly) using the Active Test function and measure the resistance according to the value(s) in the table below.

      Powertrain > Engine > Active Test 

      Tester Display
      Control the Engine Cooling Fan Duty Ratio

      Standard Resistance

      Tester Connection GTS Operation Specified Condition
      A30-2 (SI) - Body ground Before Active Test (0%) → During Active Test (100%) Before Active Test (0%): Resistance is stable → During Active Test (100%): Resistance fluctuates*

      HINT: 

      *: Using the Active Test, duty control of the transistors in the ECM will be performed. Due to the duty control, resistance of the RFC terminal will be unstable during the Active Test. If the resistance is stable before the Active Test and fluctuates while performing the Active Test, it can be determined that the transistor is operating. If the transistor does not operate during the Active Test, the ECM may be malfunctioning.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE FAN WITH MOTOR ASSEMBLY. Refer to  REMOVAL [12/2019 - 10/2021]  , or refer to  REMOVAL [10/2021 - ] 

    Result: 

    NG 

    See step  9

  9. CHECK HARNESS AND CONNECTOR (FAN WITH MOTOR ASSEMBLY - ECM) 
    1. Disconnect the A30 fan with motor assembly connector.
    2. Disconnect the A27 ECM connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A30-2 (SI) - A27-32 (RFC) Always Below 1 Ω

      Result

      Result
      OK
      NG

    Result: 

    OK 

    REPLACE ECM. Refer to  REMOVAL [12/2019 - 10/2022]  , or refer to  REMOVAL [10/2022 - 11/2023] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR (FAN WITH MOTOR ASSEMBLY - ECM) 

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