Some Frigidaire dishwashers have cycles that require the water to heat to higher temperatures. If there is a problem with the heating element and the water is not getting hot enough, the dishwasher can become stuck in this mode. Changing the setting to one that doesn't use heat will complete the cycle. At that point, you can call a repair technician about the heating element.
It's possible that the heating element is working, but the dishwasher's thermometer is not accurately reading the temperature. The thermostat should be in contact with the washing tub.
If the water is not draining properly, the dishwasher may get stuck in the cycle as it tries to eliminate the water. This is usually due to food blockages along the bottom of the machine or within the drain tubes. This may be the problem if there is still water present when you turn the machine off and open the door.
In rare cases, the timer on the dishwasher breaks and won't advance. If this is the case, you'll have to replace the timer or purchase a new dishwasher.