The most common problems with Chamberlain Liftmaster garage doors are troubles with the remote control or troubles with opening or closing the door itself. The manual that comes with the doors, however, comes with a trouble shooting guide. Additionally, some of the door openers have problem-indicator lights.
User error is the first thing to consider when having trouble with the opener remotes. Some remotes have a locking feature that the user may need to disengage to enable the door to function properly. Likewise, door-opening issues may be due to a blockage or misalignment of the safety sensors. Diagnostic codes may appear on the remote to assist in diagnosing the issue.