LIGHTING SYSTEM FAIL-SAFE CHART


  1. FAIL-SAFE


    1. Light control ECU

      The light control ECU executes the fail-safe actions listed below in accordance with the item that has been detected.

      Item Outline
      Detection of Abnormal Input Voltage

      • If voltage that is input to the light control ECU deviates from the operating voltage range (9 to 16 V), the ECU stops illuminating the headlights, and resumes illuminating the headlights once the voltage reverts to the operating voltage range

      • However, if input voltage decreases after the headlights have illuminated, the headlights will remain illuminated as long as possible
      Detection of Abnormal Output (Open or Short Circuit) If an abnormal condition (open or short circuit) occurs in voltage that is output by the light control ECU, the ECU stops illuminating the headlights and will maintain this state until power is reinstated (by turning the headlight control switch off and then on again)
      Detection of Abnormal Output Voltage to Headlights (too high or too low) If an abnormal condition (too high or too low) occurs in voltage that is output to the headlights by the light control ECU, the ECU stops illuminating the headlights and will maintain this state until power is reinstated (by turning the headlight control switch off and then on again)

    2. Headlight leveling ECU assembly

      The headlight leveling ECU assembly operates in fail-safe mode if an abnormal condition such as those listed below has been detected, and indicates the automatic headlight beam level control system warning in the multi-information display.

      Item Abnormality Detection Condition Leveling Motor Control Return Condition Warning
      Speed sensor

      • Open or short in the right front speed sensor

      • Open or short in the left front speed sensor

      • Continues operating using the normally functioning sensor if one sensor is abnormal.

      • Continues operating on the basis that the vehicle is stationary if both sensors are abnormal.

      		 Engine switch turned on (IG) again Displayed
      Height control sensor power source Short

      • Holds at the current position if its position is lower than the initial set position.

      • Returns to its initial set position and stops, if its position is higher than the initial set position.

      		 Normal value is detected Displayed
      Front height control sensor

      • Open

      • Short

      • Holds at the current position if its position is lower than the initial set position.

      • Returns to its initial set position and stops, if its position is higher than the initial set position.

      		 Normal value is detected Displayed
      Rear height control sensor

      • Open

      • Short

      • Holds at the current position if its position is lower than the initial set position.

      • Returns to its initial set position and stops, if its position is higher than the initial set position.

      		 Normal value is detected Displayed
      Headlight leveling motor LH

      • Open

      • Short

      • Overheat

      • Holds at the current position if its position is lower than the initial set position.

      • Returns to its initial set position and stops, if its position is higher than the initial set position.

      		 Normal value is detected Displayed
      Headlight leveling motor RH

      • Open

      • Short

      • Overheat

      • Holds at the current position if its position is lower than the initial set position.

      • Returns to its initial set position and stops, if its position is higher than the initial set position.

      		 Normal value is detected Displayed
      Generator L terminal

      Generator L terminal level is low

      (voltage is low)

      		 Continues normal control Engine switch turned on (IG) again Displayed

      Pitch angle

      (nose-up or nose-down vehicle posture)

      		 Out of range pitch angle is detected

      • Holds at the current position if its position is lower than the initial set position.

      • Returns to its initial set position and stops, if its position is higher than the initial set position.

      		 Normal range pitch angle is detected Displayed