After about eight years of use, the door of my LG washing machine started periodically failing to lock. It got more and more erratic, and finally failed completely. It displayed the error code dE. I found instructions online for replacing the door lock mechanism and ordered the part. It was easy to replace and took about 15 minutes. After unplugging the machine, all you have to do is remove the wire ring from around the door, pull the rubber aside, unscrew the old locking mechanism, remove it, unplug it, plug the new one in, screw it in place, and replace the wire ring. I had no previous appliance repair experience. The unit now works fine again.
The manufacturer advises resetting the machine when a dE error message is displayed. Probably best to try that first. There are instructions on their website.