What action should be taken to ensure the power steering system is functioning properly?

To ensure the power steering system is functioning properly, checking for leaks is essential. The power steering system relies on hydraulic fluid to assist in steering efforts. If there are any leaks in the system, it can lead to a loss of fluid, which will compromise the system’s ability to provide adequate steering assistance. This could make steering difficult and unsafe while driving.

When checking for leaks, it's important to inspect hoses, connections, and the power steering pump for signs of fluid accumulation or dampness. Addressing leaks promptly not only maintains the functionality of the power steering system but also helps to avoid damage to other components due to fluid loss.

While other options relate to maintenance aspects, they do not address the immediate performance and safety concerns provided by a well-functioning power steering system like checking for leaks does. For instance, ensuring inflation pertains more to tires, lubricating the shaft may relate to other mechanical parts, and ensuring the filter is clean is more relevant to other systems but does not directly impact the operation of the power steering system specifically.