Congratulations on your new car purchase. The 2.7 liter double over head cam motor has some design issues that make it a bit more sludge prone than some other motors.
Those issues are a very sharp curve in the oil galleries that provide oil to the crankshaft bearings and also these motors have a tendency to build up sludge at the timing chain area.
However, with that said good oil change maintenance goes a long way in preventing this design issues causing problems. The oil sending unit is in place to give the ECU or central computer information regarding oil pressure and flow.
It is not uncommon for these electrical/mechanical switches to fail. It is more common for sludge to form in the little inlet above the oil filter that feeds oil to the oil sending unit. If I had to bet, I would say that the little inlet got plugged up with sludge to that the sending unit was not getting a good reading.
Based on you having two bottles of Auto-Rx, I would suggest the following:
Add 1 full bottle of Auto-Rx to your next oil change fill, with a new filter installed. And run this for a normal oil change interval. That would be 3000 miles on a conventional oil, or up to 4000 miles on a full synthetic oil. I would suggest a conventional oil for the cleaning with Auto-RX, unless you are in a very cold climate.
Next add the equivalent of 1 fluid ounce of auto-rx to the existing power steering fluid. And run the car for 1000 miles. Then have the power steering fluid replaced. That will ensure that any oxidized fluid deposits are dissolved into the fluid before replacement. To give you an idea, an Auto-Rx bottle contain 12 fluid ounces. So you will be adding 1/12 of the bottles contents to the power steering reservoir.
So now you have basically an almost full bottle of Auto-Rx. After completing the 1 bottle treatment on the motor you will run an oil change interval of motor oil only. Then I would suggest you run the almost full bottle in the following oil change interval.
I hope this makes sense to you. If you have further questions please reply.
