THE BASIC PRINCIPLES OF PEUGEOT ADBLUE DELETE

Due to the fact very last diagnostics / code clearing drove 3 miles and lightweight back on / motor turned off straight away advert blue filler cap removed and attempted to blow/suck via cap to view if ventilated. Cap will not be ventilated. still left cap off and tissue in filler neck for 80 miles/no lights came on.No, Pretty much all diesel engin