A problematic hydraulic system.

Diagnose the hydraulic system. Refer to Power Steering System Test .

The power steering fluid level is low.

Add power steering fluid. Refer to Checking and Adding Power Steering Fluid .

The power steering gear valve is sticking.

1. Flush the power steering system. Refer to Power Steering System Flushing .
2. Bleed the power steering system. Refer to Power Steering System Bleeding .

If the power steering gear valve is still sticking, replace the power steering gear. Refer to Steering Gear Replacement .

The power steering pump pressure is insufficient.

1. Test the power steering system. Refer to Power Steering System Test .
2. Replace the power steering pump. Refer to Power Steering Pump Replacement .