The reason our Asko D3250 had this problem was because of a leak. The pump hose (approx. 2" black rubber hose - find it here http://www.repairclinic.com/PartDetail/Pump-Hose/8801409/1810263
) was split, causing a leak and the blinking heavy wash light. The sensor did its job and picked up the leak.
If you're handy you don't necessarily need to call a repairman in to accomplish the work. You don't need to pull the front of the dishwasher apart. Unplug the power to the dishwasher. Take off the back bottom panel. Next, test where the leak is coming from. Place pans below the holes found on the bottom of the dishwasher. They are visible when removing the back panel and are most likely at the rear of the dishwasher. Plug the power back in then start the dishwasher. If your problem is a leak, you will easily spot it with a flashlight. After ordering and installing your part, make sure to dry all water that has settled in the bottom of the dishwasher. You can easily accomplish this through the back of the dishwasher with the panel removed. If it's still damp the sensor will continue to detect water. Once dry, start the cycle to make sure there are no more leaks before reinstalling the panel.