The power steering fluid level is low.

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

The power steering pump pressure is insufficient.

Repair or replace the power steering pump. Refer to Power Steering Pump Replacement .

The power steering gear or the power steering pump has an internal leak.

Repair or replace the appropriate component as necessary. Refer to Power Steering Pump Replacement or Steering Gear Replacement .

The steering gear valve spool is sticking/damaged.

Repair or replace the power steering gear as necessary. Refer to Steering Gear Replacement .