LIGHTING SYSTEM TERMINALS OF ECU


  1. CHECK MAIN BODY ECU AND INSTRUMENT PANEL JUNCTION BLOCK (w/ Daytime Running Light System or w/ Automatic Light Control System)

    A01179UE01
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    *1 Instrument Panel Junction Block
    A011B53E01
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    *1 Main body ECU (w/ Theft Deterrent System)
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    *1 Main body ECU (w/o Theft Deterrent System)

    1. Remove the main body ECU.

    2. Measure the resistance and voltage between each terminal of the wire harness side connectors and body ground.

      Terminal No. (Symbol) Wiring Color Terminal Description Condition Specified Condition
      3F-11 (GND1) - Body ground - Ground Always Below 1 Ω
      3F-29 (ACC)*1 - Body ground - Ignition power supply (ACC signal) Ignition switch ACC → off 11 to 14 V → Below 1 V
      3F-30 (BECU) - Body ground - +B (power system signal system) power supply Always 11 to 14 V
      3F-32 (IG)*1 - Body ground - Ignition power supply (IG signal) Ignition switch ON → off 11 to 14 V → Below 1 V

      • *1: w/o Entry and Start System

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

    3. Reinstall the main body ECU.

    4. Measure the voltage between each terminal of the wire harness side connectors and body ground.

      Terminal No. (Symbol) Wiring Color Terminal Description Condition Specified Condition
      D42-1 (RFOG) - Body ground GR - Body ground Rear fog light switch input Rear fog light switch ON Below 1 V
      Rear fog light switch OFF Pulse generation
      D42-3 (HAZ) - Body ground R - Body ground Hazard warning signal switch input Hazard warning signal switch ON Below 1 V
      Hazard warning signal switch OFF Pulse generation
      D42-5 (HU) - Body ground W - Body ground Dimmer switch HIGH signal input Dimmer switch in HIGH Below 1 V
      Dimmer switch in LOW Pulse generation
      D42-8 (HF) - Body ground SB - Body ground Dimmer switch HIGH FLASH signal input Dimmer switch in HIGH FLASH position Below 1 V
      Dimmer switch not in HIGH FLASH position Pulse generation
      D42-13 (CANL) - Body ground W - Body ground CAN communication line L Ignition switch ON Pulse generation
      Ignition switch off Below 1 V
      D42-14 (CANH) - Body ground R - Body ground CAN communication line H Ignition switch ON Pulse generation
      Ignition switch off Below 1 V
      D42-20 (CLTB) - Body ground R - Body ground Automatic light control sensor power supply output Ignition switch ON and light control switch in AUTO 11 to 14 V
      Ignition switch off Below 1 V
      D42-21 (CLTS) - Body ground Y - Body ground Automatic light control sensor signal input Automatic light control system operates

      Pulse generation

      (See waveform 1)
      Ignition switch off Below 1 V
      D42-22 (CLTE) - Body ground GR - Body ground Automatic light control sensor ground Always Below 1 Ω
      D42-27 (FFOG) - Body ground P - Body ground Front fog light switch input Front fog light switch ON Below 1 V
      Front fog light switch OFF Pulse generation
      D42-28 (A) - Body ground GR - Body ground Light control switch AUTO signal input Light control switch in AUTO Below 1 V
      Light control switch not in AUTO Pulse generation
      D42-29 (HEAD) - Body ground L - Body ground Light control switch HEAD signal input Light control switch in HEAD Below 1 V
      Light control switch not in HEAD Pulse generation
      D42-30 (TAIL) - Body ground Y - Body ground Light control switch TAIL signal input Light control switch in TAIL or HEAD Below 1 V
      Light control switch in neither TAIL nor HEAD 11 to 14 V
      3B-25 (DIM) - Body ground G-Y - Body ground High beam headlight relay drive output Dimmer switch in HIGH or HIGH FLASH Below 1 V
      Dimmer switch in LOW 11 to 14 V
      3C-29 (FFGO) - Body ground R - Body ground Front fog light relay drive output Light control switch in TAIL and front fog light switch ON Below 1 V
      Light control switch in TAIL and front fog light switch OFF 11 to 14 V
      3B-34 (HRLY) - Body ground W-L - Body ground Headlight relay drive output Light control switch in HEAD Below 1 V
      Light control switch not in HEAD 11 to 14 V

      If the result is not as specified, the main body ECU may have a malfunction.


      1. A011B7SE01

        Waveform 1: Using an oscilloscope

        Terminal Name D42-21 (CLTS) - Body ground
        Tester Range 5 V/DIV, 5 ms/DIV
        Condition Ignition switch ON and light control switch in AUTO

        Tech Tips

        If the ambient light becomes brighter, width A becomes narrower.