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Home >> Toyota >> 2021 >> Highlander LE, 4WD >> Repair and Diagnosis >> Accessories & Equipment >> Exterior Lights >> Lighting System (W/O AFS) - Symptom Tests & Circuit Tests (2 Of 2) >> LIGHTING SYSTEM (w/o AFS) >> Front Fog Light Circuit [09/2020 - 11/2023] >> Procedure

Front Fog Light Circuit [09/2020 - 11/2023]: Procedure

  1. CHECK OPERATION (TAILLIGHTS) 
    1. Check the operation of the taillights.

      OK

      Taillights operate normally.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    GO TO PROBLEM SYMPTOMS TABLE. Refer to  PROBLEM SYMPTOMS TABLE [09/2020 - 10/2022]  , or refer to  PROBLEM SYMPTOMS TABLE [10/2022 - 11/2023] 

    Result: 

    OK 

    See step  2

  2. PERFORM ACTIVE TEST USING GTS 
    1. Perform the Active Test according to the display on the GTS.

      Body Electrical > Main Body > Active Test 

      Tester Display Measurement Item Control Range Diagnostic Note
      Front Fog Light Relay Front fog lights OFF or ON -

      Body Electrical > Main Body > Active Test 

      Tester Display
      Front Fog Light Relay

      OK

      Front fog light relay operates. (Front fog lights come on.)

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to  PROBLEM SYMPTOMS TABLE [09/2020 - 10/2022]  , or refer to  PROBLEM SYMPTOMS TABLE [10/2022 - 11/2023] 

    Result: 

    NG 

    See step  3

  3. CHECK HARNESS AND CONNECTOR (POWER SOURCE - FOG FR RELAY) 
    1. Remove the FOG FR relay.
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      2 (FOG FR relay) - Body ground Ignition switch off*1
      Always*2      		 11 to 14 V
      5 (FOG FR relay) - Body ground Ignition switch off*1
      Always*2      		 11 to 14 V
      1. *1: for HV Model
      2. *2: for Gasoline Model

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  4

  4. INSPECT FOG FR RELAY 

    Refer to ON-VEHICLE INSPECTION [12/2019 - ]

    Result

    Result Proceed to
    OK (except Sport Package) A
    OK (for Sport Package) B
    NG C

    Result: 

    B 

    See step  6

    Result: 

    C 

    REPLACE FOG FR RELAY 

    Result: 

    A 

    See step  5

  5. CHECK HARNESS AND CONNECTOR (FOG FR RELAY - FOG LIGHT ASSEMBLY) 
    1. Disconnect the A59 fog light assembly LH connector.
    2. Disconnect the A58 fog light assembly RH connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      3 (FOG FR relay) - A59-2 (B) Always Below 1 Ω
      3 (FOG FR relay) - A58-2 (B) Always Below 1 Ω
      3 (FOG FR relay) or A59-2 (B) - Body ground Always 10 kΩ or higher
      3 (FOG FR relay) or A58-2 (B) - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    See step  7

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  6. CHECK HARNESS AND CONNECTOR (FOG FR RELAY - FOG LIGHT ASSEMBLY) 
    1. Disconnect the B8 fog light assembly LH connector.
    2. Disconnect the B7 fog light assembly RH connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      3 (FOG FR relay) - B8-2 (B) Always Below 1 Ω
      3 (FOG FR relay) - B7-2 (B) Always Below 1 Ω
      3 (FOG FR relay) or B8-2 (B) - Body ground Always 10 kΩ or higher
      3 (FOG FR relay) or B7-2 (B) - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  7

  7. CHECK HARNESS AND CONNECTOR (FOG FR RELAY - INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY) 
    1. Disconnect the 4C instrument panel junction block assembly connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      1 (FOG FR relay) - 4C-25 Always Below 1 Ω
      1 (FOG FR relay) or 4C-25 - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  8

  8. INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY 
    GTY867902Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    *a Component without harness connected
    (Instrument Panel Junction Block Assembly)    		 - -
    1. Remove the main body ECU (multiplex network body ECU) from the instrument panel junction block assembly.

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

    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      4C-25 - MB-7 (FFGO) Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU). Refer to  REMOVAL [12/2019 - 10/2022]  , or refer to  REMOVAL [10/2022 - 11/2023] 

    Result: 

    NG 

    REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY. Refer to  REMOVAL [12/2019 - 10/2022]  , or refer to  REMOVAL [10/2022 - 11/2023] 

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