30 ES300 – NEW FEATURES Construction 1) Height Control Sensor A height control sensor, which detects the changes in the vehicle height while the vehicle is in motion, has been provided on the rear right suspension. This sensor detects the amount of variance of the vehicle height while the vehicle is being driven, and output this amount in the form of signal to the headlight leveling ECU. 2) Leveling Indicator Light The leveling indicator light is located on the combination meter. It comes on to alert the driver about system trouble when a malfunction is detected in self- diagnosis of the headlight leveling ECU.
In normal operating conditions when the igni- tion switch is turned to the ON position, the light comes on for about 3 seconds and then goes off. Leveling Indicator Light 173ES15 Operation While the vehicle is being driven, the height control sensor detects the vehicle’s posture that varies in accor- dance with the road conditions or driving conditions, and outputs the resultant signals to the headlight level- ing ECU. Based on these signals from the sensor, the leveling ECU assesses the vehicle’s posture. In addition, the Skid Control ECU sends the vehicle speed signal to the leveling ECU, allowing the leveling ECU to determine the vehicle’s driving conditions.
The leveling ECU controls the actuator so as to cancel out the changes in the light beams that are caused by these changes in the vehicle’s posture and speed. Initial Set Control When the ignition switch is turned ON, the headlight leveling ECU operates the actuator to lower the light beams to the lowest end. Then, it returns to the proper position. Thus, the leveling ECU assesses the position of the light beam that forms the reference for control.