STEERING ANGLE SENSOR
DESCRIPTION
An optical steering angle sensor is used to sense the
steering angle specified by the driver’s actions. The
steering angle sensor consists of two micro-computers
which work together with a signal measuring ring to
form one unit. There are nine LED’s that are evenly
spaced in the steering angle sensor. They are located
in a light-beam barrier which eight different lenght
blades pass through. The light-beam barriers are
located in the clockspring and only when the two com-
ponents (clockspring and the steering angle sensor)
are clipped together do they form the complete func-
tional unit of the optical steering angle sensor.
OPERATION
The optical steering angle sensor is a digital sensor with nine light-emitting diodes, and eight barrier blades. The
LED’s within the sensor are used in conjunction with the barrier blades to detect the rotation and position of the
steering wheel.
With the steering wheel in the center position, the eight blades assume a defined position in relation to the nine
LED’s. This center position is recorded by the processor in the steering angle sensor. When the steering wheel is
turned, the position of the blades change in relation to the LED’s (light/dark). A distinct signal pattern for calculating
the steering wheel angle is produced from the different length blades and the spacing of the blades. Using the
signal patterns, angle values are calculated and converted into serial information for the module.
The recording of a signal by LED’s and light-beam barriers is registered on a 2.50 degree variation and is designed
for 720 degrees of total steering angle (4 steering wheel revolutions). The steering angle sensor has continuous
battery voltage supplied by the underhood accessory fuse block. The steering angle sensor must be reinitialized
after voltage has been interrupted.
ZH
BRAKES - ABS SERVICE INFORMATION
5 - 257