Hotpoint LFT114

I went to this dishwasher before christmas started a programme which pumped out then filled with water and stopped filling but no wash motor, on taking wash motor out found that the impellor had fallen off, so i ordered a new motor which finally arrived this week. I went to fit it today and when i tested it the machine emptys then fills but after a minute it drains constant and the 1st and 3rd lights flash, can some one help with this as this wasent showing up on my 1st visit, when i opened up the motor there was a loose cone shape plastic bit loose in the housing which is nothing to do with the motor and i cant remember it last time but i think it goes over the protruding end for the heateris this corect. many thanks Andy