Do you have to reprogram the garage door keypad after changing the battery?

Whether you have to reprogram garage door keypad after changing battery depends on keypad model and how long battery was out, but generally most modern keypads retain programming and do not require reprogramming after battery change, though some may need resync. For most LiftMaster, Chamberlain, Craftsman, and Genie wireless keypads like 877MAX, keypad memory is non-volatile and PIN and programming are retained even when battery removed for short time, so after replacing dead battery with new 9-volt, AAA, or coin cell, you can immediately enter existing PIN and press Enter and door should open without reprogramming. However, if battery was dead for long time or removed for more than few minutes, some keypads may lose memory and require reprogramming by pressing Learn button on opener motor unit briefly and entering PIN on keypad and pressing Enter within 30 seconds until opener light blinks. If keypad stops working after battery change, first try existing PIN, as it may still work. If not, reprogram as described. To avoid need for reprogramming, change battery quickly within 30 seconds and use same PIN. Signs you need reprogramming include keypad lights work but door doesn't open with correct PIN after battery change. Replacement battery costs 3 to 10 dollars. Keeping spare battery and changing promptly when lights dim prevents loss of programming and being locked out.