white spinny thing wont go round?

my washer flashed f5,so i did the usual opened the black cap and checked there was nothing stuck in there,i also checked the white spinny thing was going round at the back(advised by someone on here)and it was but when i close everythin up and turn the washer on i can hear the spinny thing isnt going round (is it worked by the rush of the water or the pump)it is not easy to get my washer out of its hole as it is built in,is my only option to check the black pipe ? or do you think its the pump ? (what are the signs its the pump ?) Thank you in advace