The P0300 code indicates the PCM Misfire Monitor had detected a multiple misfire event. If you hadn't noticed any unusual engine roughness or loss of performance, it was probably set in error. There is revised PCM software avaialbe through TSB 18-016-06 to correct the erroneous setting of P0300. You will have to see your Friendly Neighborhood Dodge Boys for this update. It's covered in the 3/36 warranty, of course.
On the other hand, if you HAD noticed running problems, let me know. Thanks, Ed