Hi, My Peugeot 406 2.0 HDI gives me the message "Diesel additive minimum level", took the car to the dealer. They refilled the additive tank reset the cars computer, but I still get the same error 'Diesel additive minimum level' when starting the car and running it for about 60 sec. I unmounted the additive tank and checked that there is some additive in it, and it seems to be full. What can I do to correct the problem? How is the additive detected? Can there be a sensor problem? Br. TIH