HEADLIGHT AUTO LEVELING SYSTEM OPERATION


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Optical Axis Adjustment

•  A vehicle-height condition signal is sent to the headlight auto leveling control module from the front and rear auto leveling sensors installed to the vehicle based on the up and down changes of the suspension.
•  Based on the calculation of the optical axis adjustment amount, the headlight auto leveling control module controls the headlight leveling actuator.

Auto Headlight Leveling Operation

•  The auto headlight leveling function responds to changes in the vehicle attitude from the passenger and cargo load while the vehicle is stopped to adjust the optical axis of the headlight beams according to the change in the vehicle attitude.

Operation While Passengers Are in Rear Seat Or Under Loaded Condition

•  A vehicle-height condition signal is sent to the headlight auto leveling control module from the front and rear auto leveling sensors installed to the vehicle based on the up and down changes of the suspension.
•  When signals are detected from the front and rear auto leveling sensors, the headlight auto leveling control module determines the vehicle attitude to calculate the amount of optical axis adjustment. When the headlights are on, the headlight auto leveling control module compares the actual and optimal positions of the reflector and outputs a control signal to the headlight leveling actuator.
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Operation While Driving

•  Adjusts the optical axis once between vehicle stops to correct changes in the vehicle attitude caused while the vehicle is stopped. (Vehicle is parked with a wheel on a curb)


Fail-safe

•  The fail-safe operates when the headlight auto leveling control module detects a malfunction. It also warns the driver of a malfunction by illuminating the indicator light as shown in the fail-safe table.
•  The fail-safe controls each part as shown on the fail-safe table.

Fail-safe Table

Item

Test condition

Fail-safe

Indicator light

Cancel condition

Auto leveling sensor
Signal malfunction
Signal voltage of 4.0 V or less detected 10 times or more within 5 s
Returns headlights to the initial set position if they are pointing higher than initial set position. Fixes them in position where the malfunction is determined if pointing lower than the initial set position.
Illuminated*1
Continuous normal operation for 5 s, or ignition is switched off and then ON again.
Power supply malfunction
Power supply voltage of 0.25 V or less, or 4.75 V or more detected 10 times or more within 5 s
headlight auto leveling control module
Malfunction detected by headlight auto leveling control module
Resets microcomputer in headlight auto leveling control module.
Illuminated
Ignition is switched off and then ON again.
DSC HU/CM
Vehicle speed of 180 km/h {112 mph} or more detected
Fixes the optical axis angle at the position where vehicle speed of 180 km/h {112 mph} or more detected
Not illuminated
Vehicle speed of less than 180 km/h {112 mph} detected
Battery voltage
Excessive power supply voltage
Battery voltage of 18.1 V or more detected
Fixes headlights in position where excessive power supply voltage was determined.
Illuminated
When battery voltage of 17.5 V or less is detected, or ignition is switched off and then ON again.

*1  :Indicator light illuminates only when either malfunction condition is detected two consecutive times.
Note
•  When the ignition switch is turned to the ON position, the headlight auto leveling control module checks the auto leveling indicator light bulb and illuminates the bulb for 3 s to indicate that there is no malfunction.
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