What is the primary function of power steering fluid?

The primary function of power steering fluid is to assist in steering the vehicle easily. Power steering systems use this fluid to enable smoother and more controlled steering, especially at low speeds or when maneuvering in tight spaces. The fluid helps to transmit the force generated by the steering wheel through the system to the wheels, making it easier for the driver to turn the vehicle without excessive effort. This is particularly beneficial in a vehicle's overall drivability and enhances the driver's comfort and control while driving.

The other options address functions unrelated to steering assistance. For example, engine lubrication pertains to oil, transmission cooling involves specific transmission fluids, and cleaning the brake system is served by brake cleaners or fluids designed for that purpose. Therefore, the choice that accurately captures the primary role of power steering fluid is the one that highlights its contribution to making steering easier and more efficient.