What is a DPF Regen?   DPFs need cleaning regularly. Newer diesel vehicles have a cleaning process called “DPF regeneration”. DPF regens are active, passive or forced regeneration's. In all three methods the soot burns off at a high temperature (600°c). All that is left is an ash residue. This effectively renews or “regenerates” the DPF filter so it gets back to work filtering p...