LIGHTING SYSTEM FAIL-SAFE CHART


  1. HID HEADLIGHT SYSTEM


    1. The headlight light control ECU sub-assembly stops illuminating the HID headlights when any of the following abnormalities are detected.

      Condition Content
      Open in output side circuit

      • Stops illuminating the headlights.

      • Keeps the headlights off until the power is reinstated (by turning the light control switch from off to the head position).
      Short between output terminals

      • Stops illuminating the headlights.

      • Keeps the headlights off until the power is reinstated (by turning the light control switch from off to the head position).
      Leak between output terminal and body ground

      • Stops illuminating the headlights.

      • Keeps the headlights off until the power is reinstated (by turning the light control switch from off to the head position).
      Excessively low output voltage

      • Stops illuminating the headlights when the output voltage becomes too low (31 +/- 3 V or less).

      • Keeps the headlights off until the power is reinstated (by turning the light control switch from off to the head position).
      Excessively high output voltage

      • Stops illuminating the headlights when the output voltage becomes too high (69 +/- 4 V or more).

      • Keeps the headlights off until the power is reinstated (by turning the light control switch from off to the head position).
      Excessively high input voltage

      • Stops illuminating the headlights when the input voltage becomes too high (20 +/- 3 V or more).

      • Illuminates the headlights again when the voltage returns to the operating voltage range (10 to 16 V).
      Low input voltage

      • Stops illuminating the headlights when the input voltage becomes too low (below 6 V).

      • Illuminates the headlights again when the voltage returns to the operating voltage range (10 to 16 V).

  2. LED HEADLIGHT SYSTEM

    The headlight light control ECU sub-assembly operates in fail-safe mode if an abnormal condition such as those listed below has been detected.

    Item Abnormality Detection Condition Return Condition Multi-information Display

    Abnormal input voltage

    (High input voltage)

    		 Abnormal power source voltage (more than 17 V) is detected. Normal power source voltage (10 to 16 V) is detected. "Check Headlight System" message is displayed

    Abnormal input voltage

    (Low input voltage)*1

    		 If the power source voltage is too low (8.5 to 10 V), LED output current will be limited. (Headlights will remain illuminated.) Output current limit is canceled when the voltage returns to the specified operating voltage (10 to 16 V). "Check Headlight System" message is displayed
    If the power source voltage is too low (below 6 V), headlight operation will stop. If the voltage returns to 8.5 V or more, headlight operation will resume.
    Abnormal output

    • Open in output side circuit

    • Short between output terminal and body ground

    • Short between output terminals (Hi and Lo)

    		 Light control switch is turned from off to head position. "Check Headlight System" message is displayed

    • *1: When the headlights are on and the input voltage is between 6 and 10 V, the headlights dim.

  3. AUTOMATIC LIGHT CONTROL SYSTEM

    If the main body ECU (multiplex network body ECU) detects a malfunction in the automatic light control sensor, the main body ECU (multiplex network body ECU) performs fail-safe control to prohibit the automatic light control. If the low beam headlights and taillights are on, the lights will remain on until the light control switch is turned off.