before you start to take things apart, try the simple things first. If the remaining water is clean, then it is unlikely from physically blocked drain because all the dirty water was already drained. The controller may be confused and needs to be reset. The way to reset depends on the model. The ones I know involve pressing 2 control buttons alternately 3 times. if it is successful, all control lights will lit, and the machine will work like new. The 2 buttons are the 2 next to "start" and "cancel", for example, it may be "normal wash" and "heated dry". You can search on google for resetting your particular model.
The more complicated way to reset the controller is to unplug the power, open the control panel, take out the control board, and then re-install it". You also need a special wrench (available in HD) to open the panel.
good luck.