2005 Chevy Cobalt power steering

You need to have a tech2 scanner to diagnose this one. I wouldn't replace parts until it is diagnosed right.
There too many possiblilities.

There are various possibilties for this. It may be a loss of communication, part failure such as internal in the steering column wiring etc.

Pay attention for when it happens, you may be putting the system into overload as explained in the tsb:

However you should check the 60 amp power fuse for the power steering assist for corossion. IF okay see if you can the codes checked with the right scanner and post them.