I have found that doseurs fail on switch on as well. Were Citroen to issue details of a revised leakage rate, then things might be a little clearer but for those about to replace the doseur on a TDBX (as I shall have to do next week), It is a real pain.
Be happy: it is a way of being wise. (Confucius.)
'92 TZD Estate(Grolliffe), Gone but never to be forgotten.
'95 405 GLX TD Estate. too new to name.