Electric Power Steering, or “EPS” as it is also known, is a mechanism that helps you to steer your car. In most vehicles, the EPS relies on a electric motor to aid in turning the wheels. If you've ever driven a car with no Power Steering at all you will have certainly noticed the difference it makes.
Unlike hydraulic systems, electric power steering (EPS) doesn't use any form of hydraulic pressure to provide steering assistance. The technology is fully electric, with an electric motor providing direct assistance to the wheels. Since there is no power lost generating and transmitting hydraulic power, these systems are typically more efficient than hydraulic power steering.
Depending on the specific EPS system, an electric motor is mounted either to the steering column or directly to the steering rack. Sensors are used to determine how much steering force is required when it is applied so that the driver only has to use a minimum amount of effort to turn the steering wheel. Some systems have discrete settings that vary the amount of steering assist that's provided, and others work on a variable curve.
Because there is no fluid in an electric power steering system, leaks and fluid levels are not a problem. However, as with any software driven system, glitches can develop, and if the electric motor fails then the system will not work at all. In this case the electric motor which assists the steering will have to be replaced.