Cummins ISX15 2013 won't start and cranks over and turns off right away

[schISM]

If your nozzle moves back and forth smoothly then yes you only need the actuator if its stuck you might be able to free it up but it will probably stick again at the most inopportune time. Replace it would be better. If the acctuator wasn't installed properly for some reason it may have gone 180 and lost its reference and just needs to be properly calibrated