The power steering fluid level is the first thing to check when a whining sound is heard coming from the power steering pump. The power steering system is a critical part of an automobile and should not be ignored, or a driver may find himself unable to control the vehicle.
It's possible that a whining sound may be heard if the power steering fluid is cold and temporarily moving sluggishly. This is not generally a cause for concern, but if the sound persists, the power steering fluid needs to be checked at the reservoir. If the reservoir is depleted, there is a leak somewhere in the system. If the reservoir is full, there may be a problem with the power steering pump itself. Diagnosing a problem with the power steering pump begins with an inspection of the steering pump belt to see if an adjustment is needed. If the fluid level and the belt both look good, the next step requires raising the front of the vehicle to check the steering assembly for loose or worn parts. Cars with rack-and-pinion steering systems also require a check of the seals for leaks.
These are the most common places to look to fix a whining power steering pump. Steering problems can get quite complex, however, potentially calling for an expert opinion.