Vehicle Speed Sensor Signal: Description and Operation

The vehicle speed sensor (VSS) is located in the transmission and used to establish vehicle speed for the electronic variable orifice (EVO) steering system as follows:
^ The output current to the power steering control valve actuator is a function of vehicle speed and the steering wheel rotation rate.
^ When vehicle speed is less than 16 km/h (10 mph), the output current is less than 100 mA and full power steering assist is provided.
^ As vehicle speed increases, the current increases to approximately 600 mA. The current then remains constant at approximately 600 mA for vehicle speeds greater than approximately 144 km/h (90 mph). Conversely, as vehicle speeds decrease, the current decreases linearly.