Error code E1 keeps coming up on my Dishwasher KDW12ST3A Kenwood?

It doesn't matter what program cycle I put my dishwasher on it keeps coming up with the error code E1, I do have the manual which says, Water inlet not filling and to check if the water outlet valve is opening and there is sufficient water pressure. Have done all of this water pressure is fine, but still E1 keeps coming up...Please help, it's driving me nuts.