PRE-CRASH SAFETY SYSTEM TERMINALS OF ECU


  1. CHECK SEAT BELT CONTROL ECU

    A01G9DAE05

    1. Disconnect the H77 and H78 seat belt control ECU connectors.

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

      Terminal No. (Symbol) Wiring Color Terminal Description Condition Specified Condition
      H77-7 (+B) - Body ground B - Body ground Battery voltage Engine switch off 11 to 14 V
      H77-8 (PGND) - Body ground W-B - Body ground Body ground Always Below 1 Ω
      H78-8 (IG1) - Body ground V - Body ground Seat belt control ECU power supply Engine switch on (IG) 11 to 14 V
      Engine switch off Below 1 V

      Tech Tips

      If the result is not as specified, there may be a malfunction on the wire harness side.

    3. Reconnect the H77 and H78 seat belt control ECU connectors.

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

      Terminal No. (Symbol) Wiring Color Terminal Description Condition Specified Condition
      H77-2 (MOR+) - H77-1 (MOR-) G - B Seat belt motor RH power supply Engine switch on (IG) 4.0 to 8.5 V
      Engine switch off Below 1 V
      H77-3 (MOL+) - H77-4 (MOL-) R - W Seat belt motor LH power supply Engine switch on (IG) 4.0 to 8.5 V
      Engine switch off Below 1 V
      H78-5 (PBK+) - H78-6 (PBK-) B - W Front seat inner belt assembly RH line Engine switch on (IG), front seat belt fastened → unfastened

      Pulse generation

      (See waveform 1)
      H78-6 (PBK-) - Body ground W - Body ground Front seat inner belt assembly RH line Always Below 1 Ω

      Tech Tips

      If the result is not as specified, the ECU may be malfunctioning.

    5. Using an oscilloscope, check waveform 1.

      A01G89HE02
      Text in Illustration
      *a Front seat belt fastened *b Front seat belt unfastened
      Measurement Condition (Waveform 1)
      Item Content
      Tester Connection H78-5 (PBK+) - H78-6 (PBK-)
      Tool Setting 2 V/DIV., 20 ms./DIV.
      Condition Engine switch on (IG), front seat belt fastened → unfastened

  2. CHECK DRIVING SUPPORT ECU ASSEMBLY

    A01G7XEE05

    1. Disconnect the H75 driving support ECU assembly connector.

      Note

      Do not apply excessive force to the connector. If a force of 10 kg or more is applied, the connector may be broken.

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

      Terminal No. (Symbol) Wiring Color Terminal Description Condition Specified Condition
      H75-30 (B) - Body ground V - Body ground Power supply Engine switch on (IG) 11 to 14 V
      Engine switch off Below 1 V
      H75-5 (PBSW) - Body ground G - Body ground Pre-crash system cancel switch Pre-crash system cancel switch assembly on Below 1 Ω
      Pre-crash system cancel switch assembly off 10 kΩ or higher
      H75-25 (GND) - Body ground W-B - Body ground Body ground Always Below 1 Ω

      Tech Tips

      If the result is not as specified, there may be a malfunction on the wire harness side.

    3. Reconnect the H75 driving support ECU assembly connector.

    4. Check the pulse according to the value(s) in the table below.

      Terminal No. (Symbols) Wiring Color Terminal Description Condition Specified Condition
      H75-40 (CA1P) - H75-25 (GND) B - W-B CAN communication signal Engine switch on (IG)

      Pulse generation

      (See waveform 1)
      H75-18 (CA1N) - H75-25 (GND) W - W-B CAN communication signal Engine switch on (IG)

      Pulse generation

      (See waveform 2)
      H75-39 (CA2H) - H75-25 (GND) R - W-B CAN communication signal Engine switch on (IG)

      Pulse generation

      (See waveform 3)
      H75-17 (CA2L) - H75-25 (GND) LG - W-B CAN communication signal Engine switch on (IG)

      Pulse generation

      (See waveform 4)
    5. A01G9VDE08

      Waveform 1


      1. CAN communication signal

        Item Content
        Tester Connection H75-40 (CA1P) - H75-25 (GND)
        Tool Setting 1 V/DIV., 10 μsec./DIV.
        Condition Engine switch on (IG)
    6. A01G45VE01

      Waveform 2


      1. CAN communication signal

        Item Content
        Tester Connection H75-18 (CA1N) - H75-25 (GND)
        Tool Setting 1 V/DIV., 10 μsec./DIV.
        Condition Engine switch on (IG)
    7. A01G9VDE09

      Waveform 3


      1. CAN communication signal

        Item Content
        Tester Connection H75-39 (CA2H) - H75-25 (GND)
        Tool Setting 1 V/DIV., 10 μsec./DIV.
        Condition Engine switch on (IG)

        Tech Tips

        The waveform varies depending on the CAN communication signal.

    8. A01G45VE01

      Waveform 4


      1. CAN communication signal

        Item Content
        Tester Connection H75-17 (CA2L) - H75-25 (GND)
        Tool Setting 1 V/DIV., 10 μsec./DIV.
        Condition Engine switch on (IG)

        Tech Tips

        The waveform varies depending on the CAN communication signal.