Product review (5 stars): Our dishwasher seemed to work fine (Frigidaire FDB4315LFC0) but was showing a power failure ("PF") ...
Our dishwasher seemed to work fine (Frigidaire FDB4315LFC0) but was showing a power failure ("PF") code when complete. The dishes were also coming out very wet. I had an appliance repairman look at it and he said it was the motherboard and would only charge me $300. Since it still worked OK, I said no thanks. After a little research I found that this part is most often the reason for dishes not drying. I blindly ordered it and figured it would either work or not. After an easy install (~15 minutes), voila! - working dishwasher!

http://www.partselect.com/Models/FDB4315LFC0/Symptoms/Not-drying-dishes/