So I have a P0315 Crankshaft position system variation not learned code showing. I know I have to get it relearned. and am working at getting that done.

What i want to know is why this came on. My mods are in my sig, I have not removed the PCM. Would the tune have done this?
Thanks

 

Did you already check the crank sensor?

 

I have this same code, on a car I just bought. What would cause this, and where is the cranshaft censor at? Thanks