how do I get the www.almesberger.net/Id87/al03.html link to work?

My Hotpoint d'washer,keeps givng out AL03 error code.
Even had Hoptpoint out 12 months ago,noiw its back again doing same,help it cost £90 for their call out....
I think by the comments its aproblem in the impella housing [pump] how do i regonise this part,so I can take it aprt and rectify myself.