How can I mend my hotpoint FDUD4812 Error Code A11?

I purchased A brand new Hotpoint dishwasher model no FDUD4812 1andhalf year ago which sat in packaging until last few weeks, reason being building extension with new larger kitchen which there is room for a dishwasher space, and I plumbed it in for the very first time and it shows a error code A11= half load valve triac or alternating motor action. Unfortunately as it's been over 12months hotpoint can't come out to fix it under standard parts & labour. Any idea on the error code A11 and how to mend it please.