According to the manual, error code 4 suggests a leak into the base of the machine:
http://www.manualslib.com/manual/794947/Kenwood-Kdw12st3a.html?page=30#manual
You should be able to get the machine out and clear the water and struggle on but you need to find the leak or disgnose the floatswitch fault.
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May 2015
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