Torque is equal to the force applied to a lever multiplied by its distance from its fulcrum and again multiplied by the sine of the angle created. Usually measured in lb.-ft and differs from work or power in that torque does not necessarily produce motion.

• As Torque is being applied by turning the electronic power steering wheel, the Torque Sensor moves.
• The greater the torque and the further the magnet moves, the stronger the signal to the electronic control module (ECM). The ECM then sends a varying current to the electronic motor. This motor is splined to the ball nut. As the motor runs, the ball nut will rotate.
• This rotation will call the ball to move through the grooves in the ball nut and the helical grooves in the rack.
• A force is being applied against one end of the rack. The result is that most of the steering effort is supplied by the electric motor. 

Torque Sensor

A  Torque Sensor is a magnetic sensor device located on the pinion shaft. Its function is to send signals to the electronic control module (ECM) how much torque is being applied and in which direction