Rangemaster dishwasher E1 on RDW6051

This is a wierd fault.. it shows up error E1 but will start and continue on any program but will suddenly just stop and cut the display shortly after starting then will just start back up again sometime later, even hours later but when it works it cleans and heats fine??

Another post on here from 2011 states that E1 is a door open fault but this machines door closes and start a program so that can’t be the right code result.

Any ideas please??