What does the 'SUD' code mean on my WFW9200SQ?

The 'SUD' code means excessive suds have been detected, and the washer has automatically started a suds routine to remove the extra suds and ensure proper rinsing of garments. This is most commonly caused by using non-HE detergent; you should only use HE (High Efficiency) detergents with this washer. The cycle will complete once the extra suds are removed. (Page 20)