Fortunately I do not know very much about the crankshaft position sensor. I do know it is blamed for a lot of things but actual failure of the sensor is fortunately not all that common.

Do a search of the various forums using something like below as your search string. I think you may find that the threads for the most part say "changed the sensor and still had the problem" kind of response. It can be a bit like your temperature gauge problem - the gauge was not the problem, and the solution was a ground wire - but it was not obvious.

One solution to the crankshaft position sensor problem that I did see was just to clear the codes - in that case, once cleared, they did not reappear - that was the fix.

I did not understand your comment re RPM - it is the tach on the dash that does not show any reading or is it that there was no rpm reading on your code reader?

+crankshaft+position+sensor