There is no "closed point" nor any "open point". The controllers stops the motors when the motor current spikes. It is not smart enough to know if you have a 16", 18", or 24" slide depth. If the slide is not moving to the full open or shut position it is because something is causing the motor current to spike before it reaches the end of travel. That something may be in the slide motor/tracks area but is most likely an obstruction of the slide box itself.
So inspecting the tracks/gears is good but you also need to look under and over the slide for obstructions. Has something rolled under the slide? Extend the slide and remove the lower wiper so you can see the rollers with a flashlight.
If the slide contains plumbing and electric there is usually a "bag" containing the wires, cables, and plumbing going into the slide somewhere under the slide that can become jammed in the slide area or rollers.
Ted & Melinda
2016 ACE 27.1
2016 Chevy Sonic Toad
2020 Chevy Colorado Z71 Trail Runner Alternate Toad