HEADLIGHT AUTO LEVELING SYSTEM

2016 – MX-5 – Body and Accessories

The headlight auto leveling system automatically adjusts the headlight LO optical axis in response to changes in load and passenger conditions to prevent blinding of oncoming vehicles from headlight glare and to assure a range of visibility.

The headlight auto leveling system is controlled by the auto leveling control module/AFS control module.

If there is a vehicle height change with the ignition switched ON (engine on or off) and the headlights LO turned on, the auto leveling control module/AFS control module automatically adjusts the headlight LO optical axis.
The auto leveling control module/AFS control module controls the optical axis adjustment function based on the following signals.

Signal name	Sending module/part name	Communication method
Vehicle speed signal	PCM	HS-CAN
Ignition switch position signal	Instrument cluster
Headlight LO on condition signal	BCM
Vehicle height signal	Auto leveling sensor	Hard wire

Operation conditions

Vehicle speed is 0 km/h {0 mph} (0 km/h {0 mph} vehicle speed signal is received)
Ignition is switched ON (engine off or on) (ignition switch status signal (ON) is received)
Headlights LO on (headlight LO on condition signal reception)
Detects change in vehicle height amount^* at specified value or more

Operation

When the ignition is switched ON (engine off or on), the auto leveling sensor sends (1) a vehicle height signal to the auto leveling control module/AFS control module.
When the auto leveling control module/AFS control module receives (2) a headlight LO on condition signal from the BCM via CAN communication, it calculates (3) the amount of change in the vehicle height^* based on the vehicle height signal.
When the auto leveling control module/AFS control module detects (4) the amount of change in the vehicle height^* at the specified value or more, it calculates the target optical axis (5) based on the calculated amount of change in the vehicle height^*.
The auto leveling control module/AFS control module sends (6) the calculated target optical axis signal to the headlight leveling actuator.
When the target optical axis signal is received, the headlight leveling actuator drives (7) the motor.

^*: The change in the amount of vehicle height is the calculated 1 s average value of the vehicle height signal which the auto leveling control module/AFS control module detects every 0.1 s.

Operation conditions

Vehicle speed is 30 km/h {19 mph} or more (vehicle speed signal of 30 km/h {19 mph} or more is received)
Headlight LO on (headlight LO on condition signal reception)
Detects change in vehicle speed of 3 km/h {2 mph} or less for continuous period of 25 s
Detects change in vehicle height amount^* at specified value or more

Operation

The auto leveling sensor sends (1) a vehicle height signal to the auto leveling control module/AFS control module while the vehicle is being driven.
When the auto leveling control module/AFS control module receives (2) a headlight LO on condition signal from the BCM via CAN communication, it calculates (3) the amount of change in the vehicle height^* based on the vehicle height signal.
When the auto leveling control module/AFS control module detects (4) the vehicle speed of 30 km/h {19 mph} or more, change in vehicle speed of 3 km/h {2 mph} or less for a continuous 25 s, and the change in the amount of vehicle height^* at the specified value or more, it calculates (5) the target optical axis based on the calculated change in the amount of vehicle height^*.
The auto leveling control module/AFS control module sends (6) the calculated target optical axis signal to the headlight leveling actuator.
When the target optical axis signal is received, the headlight leveling actuator drives (7) the motor.

^*: The change in the amount of vehicle height is the calculated 1 s average value of the vehicle height signal which the auto leveling control module/AFS control module detects every 0.1 s.