LIGHTING SYSTEM FAIL-SAFE CHART


  1. HID Headlight System

    The light control ECU 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 input 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. Automatic Headlight Beam Level Control System


    1. The headlight leveling ECU operates in fail-safe mode if an abnormal condition such as those listed below has been detected.

      Item Abnormality Detection Condition Return Condition Warning Indicator
      Height control sensor power source voltage Abnormal height control sensor power source voltage (4.6 V or less) is detected. Normal voltage is detected 50 times consecutively Illuminated
      Height control sensor signal voltage Abnormal height control sensor signal voltage (0.25 V or less, or 4.75 V or more) is detected.
      High power source voltage Abnormal high power source voltage (18.5 V or more) is detected. Voltage of 17.5 V or less is detected Not illuminated
      Low power source voltage Abnormal low power source voltage (9.0 V or less) is detected. Voltage of 9.3 V or more is detected for 0.1 seconds Not illuminated
      Vehicle speed Abnormal high speed of 180 km/h (113 mph) or more is detected. Speed of less than 175 km/h (109 mph) is detected Not illuminated
      Reset while running Reset by a temporary blackout, etc. while running. Vehicle is stopped Not illuminated

  3. Automatic Light Control Function


    1. If the main body ECU detects a malfunction in the automatic light control sensor, the main body ECU performs fail-safe control to prohibit the automatic light control.


      • If a problem occurs in the automatic light control system when the light control switch is in the AUTO position and the headlights or taillights are on, the main body ECU will keep the lights on until the light control switch is turned off or the conditions for activating the headlight auto turn off system are met.

      • If a problem occurs in the automatic light control system when the light control switch is in the AUTO position, and both headlights and taillights are off, the main body ECU will interrupt the automatic light control system operation and keep both headlights and taillights off until the output from the automatic light control sensor is determined to be normal.