The learn (teach/setup) cycle lets the control automatically measure the door’s open and closed positions, weight, and travel so it can set speeds and force correctly. Run it after any mechanical change — replacing a motor/MDU, adjusting belt tension, changing door panels, or after a control-board swap — and whenever the door behaves erratically. Put the program switch into setup, initiate the learn per the ESA service manual for that control generation, and let the door complete several uninterrupted full cycles. Do not obstruct the door during the learn or the resulting travel map will be wrong.