I have a whirlpool duet front load wash machine- it keeps freezing up and flashes the word sud

This is what the code book says that could be you problem. Overdose of detergent detected during the wash cycle. this may signify a bad pump, an extra heavy load, excessive detergent or excessive suds.
If to much soap was used run the unit through a rinse/spin cycle than a normal cycle without add any soap. this should clear the unit of the excess soap.
check the drain hose and make sure it is not plugged or kinked.
check wire harness connections to the drain pump,pressure switch, and central control unit.
check/ clean drain pump filter of foreign objects.
check drain pump
check the pressure switch
check CCU.
Replace failed component. Hope this helps