The steering system allows the driver to control the direction of the vehicle. When the driver turns the steering wheel, the movement is transferred to the steering gear, either rack and pinion or recirculating ball, which changes the motion from rotary to linear. The linear motion travels through the steering linkage or tie rod that are attached to the steering-knuckles. The steering knuckles pivot either inward or outward and move the wheels and tires in the corresponding direction.
Most modern vehicles are equipped with power steering which uses a hydraulic pump or electric motor to assist the driver's efforts. But the basic operation of the steering system is the same in either manual steering or power steering.
Most manufacturers will cover the components of the steering system under the bumper-to-bumper warranty section of the factory warranty. There are extended auto warranties available that will extend coverage to the steering system after the factory warranty has expired.