aeg 6955 code f1?

I have an AEG 6955 washing maching about 14 years old.
Recently the program has stopped on many occasions with code F1 usually on first fill. Other times it works OK.
The manual says this is no water. Water is on, pipe not linked, filters not blocked.
Sometimes it does it several tiumes in a row and if I turn a nearby cold tap on and off quickly to give a pulse in the pressure

whils it is filling, it starts working OK.
Is this indicative of a the main water valve failing? and would it be cured by replacing it please?