What is ewm in sap? SAP EWM - Overview. SAP Extended Warehouse Management (EWM) is used to efficiently manage inventory in the Warehouse and for supporting processing of goods movement.What if i have problems accessing the ewm system? If you have problems accessing the EWM System, please contact EWM Participant Services.How do ewm and erp communicate with each other? SAP ERP and EWM are closely integrated with each other for transfer of transaction and master data. There are two different ways of communication. Core Interface (CIF) − Core interface is one of the common method for communication between SAP SCM system and SAP Advanced Planning and Optimization APO.