There is a stuck or inoperative flow control valve.

Replace or clean the valve.

The pressure plate is not flat against the cam ring.

Replace the pressure plate.

There is extreme wear of the cam ring.

1. Replace the cam ring.
2. Flush the system. Refer to Power Steering System Flushing .

There is a scored pressure plate, thrust plate, or rotor.

1. Replace any scored parts.

If the rotor is scored, replace the rotor with a rotating group.

2. Flush the system.

Refer to Power Steering System Flushing .

The vanes are sticking in the rotor slots.

Free the vanes by removing any burrs, varnish or dirt.

There is improper installation of the vanes.

Properly install the vanes. Ensure that you install the radius edge to the outside.

There is air in the fluid.

Locate and repair the leak.

There is low power steering fluid.

Add the necessary amount of power steering fluid. Refer to Checking and Adding Power Steering Fluid .

The pump belt is slipping.

Refer to Drive Belt Replacement in Engine Mechanical - 4.3L or Drive Belt Replacement in Engine Mechanical - 4.8L, 5.3L, 6.0L.

There are damaged hoses or steering gear.

Replace any damaged parts.