Have you ever had it working properly i.e is it brand new
If you have No 1 light flashing normally it's because the filter is clogged with bits of food or possibly bits of plastic off the sealed dishwasher tablets. Also if its brand new it could still have some packing present left in the dishwasher.
However our problem was when the machine was brand new we couldn't get it to run longer than 1 minute. After trying everything we found a black plastic "top hat" seal in the end of the cold water inlet pipe that hadn't been removed by the installers when they installed the unit initially.
dik56, April 2008