AI Perception Range

Hi, im working on AI to my project, i have almost finished it but now i passed 2 days trying to figure it out how to reset his location if he runs into a certain distance between himself and his spawn position.
I want him to be able to run like 2000 unites from his spawn position and go back to his position if he hits that 2000 distance between himself. Made it with pawnsensing but im getting problems with perception. Can u guys give me a litle clue pls?