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IG Signal Circuit [12/2019 - 11/2023]: Procedure

  1. READ VALUE USING GTS 
    1. Read the Data List according to the display on the GTS.

      Body Electrical > Main Body > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      IG SW Ignition switch ON signal OFF or ON OFF: Ignition switch off
      ON: Ignition switch ON      		 "OFF" is also displayed for this item when the ignition switch is ACC.

      Body Electrical > Main Body > Data List 

      Tester Display
      IG SW

      OK

      Normal conditions listed above are displayed.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to  PROBLEM SYMPTOMS TABLE [12/2019 - 11/2023]  

    Result: 

    NG 

    See step  2

  2. CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT) 
    1. Disconnect the 4F and 4B instrument panel junction block assembly connectors.
    2. Disconnect the H42 main body ECU (multiplex network body ECU) connector.
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      4F-1 - Body ground Always*1
      Ignition switch off*2      		 11 to 14 V

      *1: for Gasoline Model

      *2: for HV Model

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

      Standard Resistance

      Tester Connection Condition Specified Condition
      4B-3 - Body ground Always Below 1 Ω
      H42-19 (GND2) - Body ground Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  3

  3. INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY 
    GTY857137Courtesy 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
      4F-1 - MB-32 (IG) Auxiliary battery not connected to 4A-17 and 4B-3 10 kΩ or higher
      4F-1 - MB-32 (IG) Auxiliary battery positive (+) → 4A-17
      Auxiliary battery negative (-) → 4B-3      		 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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