samsung 5E error code?

i keep getting the error code and the machine will not empty. the only way it will empty is to use the emergency drain hose and drain away about 5-6 liters of water then the machine will carry on as if nothing as happened(i have to drain the water off before the code appears) I've cleaned the filter ,checked the two impeller pumps and all looks well.as I say the machine does pump the water away but only when a amount has been drained off manually.the model number is q1457v and it's about 3 years old.