whirlpool washing machine f13 error code

hello just had lady on phone saying her washing machine is 1 year and four days old, and she is in dispute with currys and whirlpool. and needs an engineers report. the error code is F13, the fault code guide says,Dispensor circuit error, has anyone had this problem,if so is it likely to be valves, wiring, or main board fault. or am i barking up the wrong tree.
thanks Darren.