I just got this code yesterday and drove about 200 miles on it to get home.

My main question her is, should I start fixing possible causes for this starting with the least expensive first?

And does anyone know where the oil pressure switch and ECM is on this make and model?

Thank you so much in advance. I'll be back periodically through the day.

 

You did not state whether this is a 4 or 6 cylinder. But, most likely based on the trouble code, it is a 4 cylinder. The location of the oil pressure switch is dependent on whether it is the PZEV engine or not.

PCM is located in the engine bay, next to the car battery.

See this technical service bulletin regarding the trouble code and replacement of the respective oil pressure switch.