AdBlue Metering Unit (Dosing Module) Genuine Mercedes Workshop Equipment Thanks to its 2 high performance Osm Accessories Thanks to its 2 high performance internal lead batteries Fleetguard® UF101 Diesel Exhaust Fluid (DEF) filter is part of the range of DEF filters offered for Cummins and non Cummins engine applications for medium duty and heavy duty truck applications that are designed to meet or exceed EPA emission standards The dosing module in heavy duty vehicles serves a similar function to that in passenger vehicles It is a device responsible for delivering a dosing fluid (most commonly AdBlue or DEF) to the SCR system