NOT KNOWN FACTS ABOUT PEUGEOT ADBLUE DELETE

Due to the fact previous diagnostics / code clearing drove 3 miles and light-weight back again on / motor turned off straight away advert blue filler cap taken out and tried to blow/suck through cap to view if ventilated. Cap isn't ventilated. left cap off and tissue in filler neck for 80 miles/no lights came on.When you purchase by means of backli