The power steering warning light indicates a fault in the power steering system. Depending on whether your car has hydraulic or electric power steering, the cause and response differ.
Hydraulic power steering
Older and some current cars use hydraulic power steering, powered by a pump driven by the engine via a belt. The system uses hydraulic fluid. A warning light or sudden loss of steering assistance on a hydraulic system is most commonly caused by: low power steering fluid (check the reservoir and top up if low); a broken or slipping drive belt; a failed power steering pump; or a leak in the hydraulic lines.
Electric power steering (EPS)
Most cars built after around 2010 use electric power steering, with a motor assisting the steering column directly. These systems have no fluid. A warning light or loss of assistance on an EPS system indicates an electronic fault: a failed torque sensor, a motor fault, or an ECU issue. These require diagnostic equipment to identify.
What it feels like when it fails
Without power steering assistance, the steering wheel becomes noticeably heavier, particularly at low speeds and when parking. At motorway speeds the car will still steer, but urban manoeuvring requires significantly more effort.
Is it safe to drive
You can steer the car without power assistance, so it is not immediately dangerous at road speeds. However, the increased effort required, particularly in emergency situations, reduces your ability to react quickly. Have it investigated promptly rather than driving with it for an extended period.
If your power steering warning light has appeared, call Steins Garage on 0131 554 3423 or get in touch here and we will diagnose the cause.