Inside the washing cabinet - right at the bottom under the filters is the impeller of the drain pump with a simple plastic cover held in place by a single Torx screw.
It is not uncommon for lemon pips and other food debris to get trapped under the impeller blades - tweezers will help to remove the crud.
Of course - the problem might always be more serious - but you can hope.
Good Luck..., May 2016
