I say again, the program controls the steppers. The material is irrelevant.

WB is right in that Nylon requires a higher temp thus an all metal hotend is better. This will have no effect on the stepper that drives the HBP. The program is either corrupt/incomplete or you are running over USB.

1) Save files to PC, not directly on SD card.
2) Do not use USB. Run programs off SD card.
3) Try formatting SD card (FAT 32) and eject card correctly.

If you have not had a single complete print since your first ABS print then it could be a hardware error, although I doubt it. Do the above first.