Chrysler Repair: Code #551 Power Steering Sensor, power steering pump, crowfoot wrench

Question
Twice in the last few days, at speeds of 60 or so, my 95 Neon's check engine light's come on, and I stopped by my friendly mechanics'.  He put it on a reader, and got the error code 551, which is for the power steering sensor.  A little research says it means "The power steering switch may not be working. (Neons: high pressure is showing up at high speed)" but what does that translate to in dollars?  I can't even SEE the power steering pump-  how much is going to have to come off to figure this out?

There doesn't seem to be anything wrong with the steering,  sometimes it seems a bit light in the front end at high speeds, but it's always done that (this is the most skittish car on ice or wet roads-  all that weight on the front end and it's still too light!)  A year or so ago, a tire guy told me I had a "loose tie rod" but when I had new tires put on a few months ago, they said nope-  looks good.  There's no pull, or shake/vibration-  whaddya think?  

Answer
Hi Julie,
The purpose of the switch is to raise the idle speed of the engine when you are turning the steering wheel at very low or no velocity (e.g. parking) so the engine doesn't die. It should not be detecting such a load on the steering system when you are going down the highway at 60. It means that sensor switch mounted on the steering gear itself, not on the pump, is sending a false signal. It is accessible from under the car with a crowfoot wrench for removing it. It might be bad, the wiring or the connector to it may be damaged or loose, or the engine computer may be in error. Most likely it is the switch itself. I wouldn't be too worried about this, unless you are bothered by the elevated idle speed and its attendant loss of fuel economy. But it is a fairly inexpensive repair as repairs go these days, in my estimation though I haven't actually priced it out. All the mechanic has to do is unclip the electrical connector and unscrew the old one, insert the new one, and top off the power fluid reservoir, (or simply clean the contacts/repair the wires if that is the issue rather than the switch itself). A couple of electrical measurements will tell which is the solution. I have the troubleshooting pages for it if you would like to have your friendly mechanic have them to do the diagnosis. Just write back with a mailing address and I'll send you the xerox copied pages.
Roland