LIGHTING SYSTEM FAIL-SAFE CHART


  1. Headlight control ECU

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

    Item Outline
    Detection of abnormal input voltage (High input voltage) If voltage that is input to the headlight control ECU is approximately 20 V or more, the ECU stops illuminating the headlights, and resumes when the voltage drops to 16 V or less.
    Detection of abnormal input voltage (Low input voltage) If voltage that is input to the headlight control ECU is 6 V or less, the ECU stops illuminating the low beam headlights, and resumes when the voltage is 10 V or more.

    Detection of abnormal output


    • Open in output side circuit

    • Short between output terminals

    • Short between output terminal and body ground

    		 If an abnormal condition occurs in the voltage that is output by the headlight control ECU, the ECU stops illuminating the low beam headlights and will maintain this state until the power is reinstated (by turning the headlight dimmer switch from OFF to HEAD position)
    Detection of abnormal light voltage (Low light voltage) After approximately 80 seconds since input voltage is supplied, if the light voltage is below approximately 31 V for approximately 0.5 seconds, the headlight control ECU stops illuminating the low beam headlights and will maintain this state until the power is reinstated (by turning the headlight dimmer switch from OFF to HEAD position)
    Detection of abnormal light voltage (High light voltage) If the light voltage is above approximately 69 V for approximately 0.5 seconds, the headlight control ECU stops illuminating the low beam headlights and will maintain this state until the power is reinstated (by turning the headlight dimmer switch from OFF to HEAD position)

  2. AFS (Adaptive Front-lighting System)

    If the AFS ECU detects a malfunction in the automatic headlight beam level control system or intelligent AFS, it will take the actions indicated in the table below.

    Trouble Area Leveling Fail-safe Control Swivel Fail-safe Control
    Headlight Swivel Motor Malfunction Continues to control with both headlight leveling motors lower than current position by 0.65° Stops malfunctioning swivel motor at current position
    Steering angle sensor Signal Malfunction Continues to control Returns both headlight swivel motors back to front
    Speed Sensor Signal Malfunction Continues to control After 5 seconds, returns both headlight swivel motors back to front
    Height Control Sensor Signal Malfunction

    • Stops operation after returning to initial position (Fail at higher than initial position)

    • Stops operation at current position (Fail at lower than initial position)

    		 Returns both headlight swivel motors back to front
    Headlight Swivel Motor (Leveling Portion) Malfunction

    Normal side headlight swivel motor (leveling portion)


    • Stops operation after returning to initial position (Fail at higher than initial position)

    • Stops at current position (Fail at lower than initial position)

    		 Returns both headlight swivel motors back to front

    Abnormal side headlight swivel motor (leveling portion)


    • Stops at current position
    Communication Signal Malfunction

    Skid control ECU:


    • Judges that vehicle speed is 0 km/h (0 mph) and continues control

    		 Returns both headlight swivel motors back to front

    Steering angle sensor:


    • Continues to control

  3. AUTOMATIC HIGH BEAM SYSTEM (w/ Automatic High Beam System)


    1. The main body ECU (driver side junction block) 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
      Speed Sensor Signal Malfunction Abnormal speed sensor signal is detected. Normal speed sensor signal is detected. System check screen is displayed
      CAN Communication Signal Malfunction Normal CAN communication signal is not detected for more than 5 seconds consecutively. Normal CAN communication signal is detected. System check screen is displayed
      Automatic High Beam Sensor Communication stopped for 10 seconds consecutively. Normal communication signal is detected. System check screen is displayed

  4. ADAPTIVE HIGH BEAM SYSTEM (w/ Adaptive High Beam System)

    If the AFS ECU detects a malfunction in the adaptive high beam system it will take the actions indicated in the table below.

    Malfunctioning Part Detection Condition Leveling Fail-safe Control Swivel Fail-safe Control Adaptive High Beam System Fail-safe Control High Beam Fail-safe Control Return Condition Master Warning Indicator Multi-information Display
    AFS ECU Power supply line open circuit

    • When higher than the initial position, the motor returns to the initial position.

    • When lower than the initial position, the motor remains in that position.

    		 Returns both headlight swivel motors to the front-facing position. Indicates low beam condition (changes to manual operation using switch) Indicates lights are off (changes to manual operation using switch) Normal condition is detected. On System check screen is displayed
    Power supply line short to ground
    Headlight Shade ECU

    • AHS actuator short circuit malfunction

    • AHS actuator open circuit malfunction

    		 Only low beam control continues. Only low beam control continues. Indicates low beam condition (changes to manual operation using switch) Indicates lights are off (changes to manual operation using switch) Engine switch is turned on (IG) again. On System check screen is displayed
    Communication error Only low beam control continues. Only low beam control continues. Indicates low beam condition Normal condition is detected.
    Source overvoltage malfunction - - Indicates low beam condition - Normal condition is detected. Off System check screen is not displayed
    Headlight Shade ECU Drive IC overheating Only low beam control continues. Only low beam control continues. Indicates low beam condition (changes to manual operation using switch) Indicates lights are off (changes to manual operation using switch) Engine switch is turned on (IG) again. On System check screen is displayed

    • Open circuit malfunction in wire harness between Headlight shade ECU and AHS actuator

    • Short to ground in wire harness between Headlight shade ECU and AHS actuator

    • Open circuit malfunction in wire harness between AFS ECU and Headlight shade ECU

    • Short to ground in wire harness between AFS ECU and Headlight shade ECU

    		 Normal condition is detected.
    Headlight Swivel Motor Communication error Continues control with both headlight swivel motors (leveling portion) lower than the current position by 0.65°. Returns both headlight swivel motors to the front-facing position. Indicates low beam condition (changes to manual operation using switch) Indicates lights are off (changes to manual operation using switch) Normal condition is detected. On System check screen is displayed

    • Hunting malfunction

    • Motor lock malfunction

    • Hall IC malfunction

    • Movement range malfunction

    • Overheat malfunction

    • Driver IC overcurrent malfunction

    • False detection due to disturbance

    		 Engine switch is turned on (IG) again.
    Source voltage malfunction - - - - - Off System check screen is not displayed
    Headlight Swivel Motor Wire harness power supply line open circuit malfunction Continues control with both headlight swivel motors (leveling portion) lower than the current position by 0.65°. Returns both headlight swivel motors to the front-facing position. Indicates low beam condition (changes to manual operation using switch) Indicates lights are off (changes to manual operation using switch) Normal condition is detected. On System check screen is displayed
    Wire harness power supply line short to ground
    Wire harness ground line open circuit malfunction
    Wire harness communication line open circuit
    Wire harness communication line short to ground
    Headlight Swivel Motor (Leveling Portion) Communication error

    • When higher than the initial position, the motor returns to the initial position.

    • When lower than the initial position, the motor remains in that position.

    		 Returns both headlight swivel motors to the front-facing position. Indicates low beam condition (changes to manual operation using switch) Indicates lights are off (changes to manual operation using switch) Normal condition is detected. On System check screen is displayed

    • Hunting malfunction

    • Motor lock malfunction

    • Hall IC malfunction

    • Movement range malfunction

    • Overheat malfunction

    • Driver IC overcurrent malfunction

    		 Engine switch is turned on (IG) again.
    Source voltage malfunction - - - - - Off System check screen is not displayed
    Headlight Swivel Motor (Leveling Portion) Wire harness power supply line open circuit malfunction

    • When higher than the initial position, the motor returns to the initial position.

    • When lower than the initial position, the motor remains in that position.

    		 Returns both headlight swivel motors to the front-facing position. Indicates low beam condition (changes to manual operation using switch) Indicates lights are off (changes to manual operation using switch) Normal condition is detected. On System check screen is displayed
    Wire harness power supply line short to ground
    Wire harness ground line open circuit malfunction
    Wire harness communication line open circuit
    Wire harness communication line short to ground
    Headlight Headlight control ECU open circuit Continues control. Only low beam control continues. Indicates low beam condition (changes to manual operation using switch) Indicates lights are off (changes to manual operation using switch) Engine switch is turned on (IG) again. On System check screen is displayed
    Open circuit or short to ground in wire harness between Headlight shade ECU and light failure indicator sensor
    Inner Rear View Mirror (Adaptive High Beam System Sensor) Communication error Only low beam control continues. Only low beam control continues. Indicates low beam condition (changes to manual operation using switch) Indicates lights are off (changes to manual operation using switch) Normal condition is detected. On System check screen is displayed
    Camera malfunction Engine switch is turned on (IG) again.
    Beam axis deviation Replace inner rear view mirror (adaptive high beam system sensor).
    Beam axis not adjusted Normal condition is detected. Off System check screen is not displayed
    Vehicle determination information malfunction On System check screen is displayed
    Vehicle determination information not registered
    Camera beam axis initialization not completed Vehicle initialization is performed.
    Vehicle control information malfunction Sensor is no longer malfunctioning
    Camera detection not possible Off System check screen is not displayed
    Camera high temperature malfunction
    Abnormal coordinate value received Normal condition is detected. On System check screen is displayed

    • Open in circuit

    • Short in circuit
    Steering angle sensor Communication error Only low beam control continues. Returns both headlight swivel motors to the front-facing position. Indicates low beam condition (changes to manual operation using switch) Indicates lights are off (changes to manual operation using switch) Normal condition is detected. On System check screen is displayed
    Steering angle sensor malfunction Engine switch is turned on (IG) again.
    Zero point invalid - - - - - Off System check screen is not displayed
    Steering Control ECU Communication error Only low beam control continues. Returns both headlight swivel motors to the front-facing position. Indicates low beam condition (changes to manual operation using switch) Indicates lights are off (changes to manual operation using switch) Normal condition is detected. On System check screen is displayed
    VGRS malfunction Engine switch is turned on (IG) again.
    Skid Control ECU Communication error Judges that vehicle speed is 0 km/h (0 mph) and only low beam control continues. Returns both headlight swivel motors to the front-facing position. Indicates low beam condition (changes to manual operation using switch) Indicates lights are off (changes to manual operation using switch) Normal condition is detected. On System check screen is displayed
    Wheel speed sensor malfunction Sensor is no longer malfunctioning
    Outer Mirror Switch Communication error Continues control. Continues control. Continues control. Continues control. Normal condition is detected. On System check screen is displayed
    Windshield Wiper Switch Communication error Only low beam control continues. - - - Normal condition is detected. On System check screen is displayed
    Main Body ECU Communication error Only low beam control continues. - - - Normal condition is detected. On System check screen is displayed
    ECM Communication error Continues control. Continues control. Continues control. Continues control. Normal condition is detected. On System check screen is displayed
    TCM Communication error Continues control. Returns both headlight swivel motors to the front-facing position. Indicates low beam condition (changes to manual operation using switch) Indicates lights are off (changes to manual operation using switch) Normal condition is detected. On System check screen is displayed
    Height Control Sensor Height control Sensor malfunction

    w/ Air Suspension:


    • When the initial position is +/-0.2% or more, returns to initial position.

    • When the initial position is less than +/-0.2%, stops at current position minus 0.2%.

    w/ Coil Suspension:


    • When higher than the initial position, the motor returns to the initial position.

    • When lower than the initial position, the motor remains in that position.

    		 Returns both headlight swivel motors to the front-facing position. Indicates low beam condition (changes to manual operation using switch) Indicates lights are off (changes to manual operation using switch) Detects normal value. On System check screen is displayed
    Source voltage malfunction
    AFS ECU Chassis information not determined Stops at initial position. Returns both headlight swivel motors to the front-facing position. Indicates low beam condition (changes to manual operation using switch) Indicates lights are off (changes to manual operation using switch) Engine switch is turned on (IG) again. On System check screen is displayed
    Destination information not determined Continues control.
    AFS destination information not determined Stops at initial position.