Question
Good Day,

I have a Toro ECx Automatic Sprinkler System Timer. It will not stay in the "Off" position for more than 15 minutes, the only thing I can do is unplug power to it. I can't tell if the dial has a short in it. For instance, I just turned it off because I don't want it to run any more this month. The LED display reads Off......15 minutes later it will show the time and day and it will run tomorrow morning at 5am.

Answer
I would take the controller to a authorized toro dealer and see if they will warranty the item. The type of issue you are having there is not much you can do besides replacing the controller it may have either suffered a power surge or suffered another internal problem which has stopped it from functioning properly.  If you have another question please ask and I will reply after the holiday weekend when I get back to work.