2000 Dodge Neon OEM Code P0551

My check engine light came on so I had the code checked at my local Auto Zone. It was a P0551. Power steering pressure switch condition.

Last week I was low on power steering fluid so I added some (first time ever adding fluid).

There is also a very high pitch squeel while driving after the car warms up, which I figured were my brakes since I am due for new brakes.

Without going into a huge repair bill that I can not afford at the moment, how can I begin to troubleshoot this situation to find the problem.

Also, could this be a dangerous problem? I have a 16 year old learning to drive and don't want him behind the wheel if it could be dangerous.

I do appreciate any suggestions or help that you may be able to give me.