Steering Angle Sensor: Description and Operation

An optical shock absorber electronic steering wheel rotation sensor (photocell), mounted on the lower steering column, is used to establish the rate of the steering wheel rotation.
^ When the steering wheel rotation rate reaches 30 rpm (15 rpm for air suspension model), the output current to the power steering control valve actuator begins to reduce, providing additional power steering assist.
^ Once the steering wheel rotation rate reaches 60 rpm or greater, the output current to the power steering control valve actuator reaches zero and full power steering assist is provided.
^ After the steering wheel rotation rate drops below 30 rpm, the output current returns to the amount of current regulated by the vehicle speed sensor input within one second.