what is the use of power steering pressure sensor in car?
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.