Steering Angle Velocity Sensor
The steering angle velocity sensor is installed at the steering column, and is used to output steer angles to the AWD-ECU as signals. It is composed of the slit plate which rotates according to the movements of the handle and a three-set photointerruptor. The slit plate and photointerruptor have a sealed integrated structure to prevent the invasion of foreign particles and interference of external light. To detect malfunctions of the sensor output circuit, it is equipped with a zener diode for detecting disconnection parallel to the phototransistor. The ECU calculates the steering angle by reading the signals of the steering angular velocity sensor after every certain period of time and calculating the total of the ST-1 signal and ST-2 signal. The steering angle is obtained by taking the neutral position (ST-N output is L center) as 0°, and if there are changes, the steering angle is added with 2° for right and -2° for left. The output of the photointerruptor becomes L (low) when light passes through and H (high) when obstructed.