On the Duet SPORTS, if they don't have a LED digital display the flashing washing status indicator lights is giving you an error code depending on which of the status lights are flashing.

If you remove the lower panel there should be a tech sheet in a plastic pouch glued to the lower kick panel.

It will have all the Fxx error codes that you would see if you had a display, under each code it should tell you what flashing lights would indicate that particular code. The tech sheet also has all the info you need to put it into diagnostics and check for any prior stored errors codes.

If you try to run the machine or do any diagnostics you must either reinstall the lower kick panel or tape the ground loop switch in the lower left corner closed, (if you don't you will get false F28 communication errors).

Source: WFW8300ASW00 - Whirlpool Duet Sport front-load washer