In the context of car sales, PAS refers to power assisted steering. Power steering systems reduce the amount of physical effort a driver needs to use to turn the steering wheel.
Until recently, most cars came equipped with a standard hydraulic power assisted steering system. One of the drawbacks of hydraulic PAS systems is that a loss of steering fluid could cause the steering wheel to seize. However, most car manufacturers are now equipping their vehicles with EPAS, or electric power assisted steering systems. One of the main benefits of an electric steering system is that it increases gas efficiency.