How do you reset an automatic garage door?

To reset an automatic garage door and opener system to restore function after malfunction, power outage, or sensor issue, you need to reset opener logic board, re-engage trolley, and reprogram limits and remotes. First, ensure door is closed manually if possible and no obstructions in tracks. To reset logic board that controls automatic operation, unplug garage door opener from power outlet for 30 seconds to a minute, then plug back in, which clears error codes and resets board. If trolley is disconnected from emergency release cord pulled, which disconnects door from opener for manual operation, re-engage by pulling emergency cord toward door or pulling cord toward opener and then running opener until trolley clicks and reconnects to door arm. Reset travel limits if door doesn't open fully or close fully: for older openers with limit screws, adjust open and close limit screws on opener unit with screwdriver; for newer LiftMaster openers with electronic limits, press and hold up and down limit buttons until they blink and set open and close positions using wall console. Reset safety sensors by cleaning lenses and aligning until LEDs solid, sending yellow and receiving green. To reset remotes and keypad, press and hold Learn button on opener for 6 seconds to erase all, then reprogram each remote by pressing Learn briefly and pressing remote within 30 seconds. If wall console has lock mode, hold lock button 5 seconds to unlock. Test automatic operation several times.