hotpoint wf210

hi..i had a call to a wf210 last week..the pre wash light was flashing and the machine was not working…i soon found there was no cold water supply and as a plumber had recently done work there advised she call him back…the supply has now been fixed ..washer fills and seems ok but pre wash light is still flashing.. i read somewhere its a no fill warning..any ideas why it would still be flashing?..going back later..thanks