How Electric Power Steering Work

Here’s an in-depth look at how electric power steering works in your car! In this video we look at column-mounted electric power steering from a 2004 Toyota Prius. The steering rack and entire steering column is taken apart and dissected to see what’s inside and how it works. The main components include the steering wheel, airbag, clockspring, turn signal switches, steering column, torque sensor, “rotary valve”, EPS motor with drive gear, EPS computer, intermediate shaft and steering rack. The steering works as a closed loop control system. The torque sensor supplies the input to the EPS computer which indicates the driver’s intended direction of steering rotation. The steering shaft has a small torsion beam that moves, triggering a change in the coil’s magnetic field relative to the reference signal inside the torque sensor. This signal is processed and sent to the EPS computer. The computer will then take a high current contact and complete the circuit for the EPS motor, which operates at