Can you explain how I can tell if my DPF filter is regenerating or not? My vehicle is a 2007 Peugeot 407 HDI. Diane Carey
For the regeneration process to take place, the engine must be up to working temperature. Once this is achieved while driving on major A-roads and motorways, the process will take place without any driver input. If insufficient driving at cruising speeds is undertaken, the vehicle will indicate that the DPF regeneration needs to take place.
When the warning light illuminates, the vehicle should, if possible, be driven at a speed above 40mph until the light extinguishes, indicating the process is complete. If this action is not taken then the filter may block beyond the point where it can self-regenerate and may need to be taken to a workshop to complete the process.