# DPF regeneration: how the filter cleans itself and what to do when the light is on _Updated: 8 November 2026_ **Short answer:** DPF regeneration is the burning of soot in the DPF, the particulate filter in a diesel exhaust, and the car does it by itself while you drive. When the DPF light is on, drive for about 10 minutes faster than 65 km/h; if the light doesn't go off or the car loses power, the filter is too full and needs a forced regeneration. > **The service we recommend: DPF cleaning** A clogged DPF: cause check, regeneration, cleaning or a new filter. We tell you the price when you tell us the model. [More about the service](https://autoindustrija.rs/en/services/dpf-cleaning) ## How DPF regeneration works The DPF catches soot from diesel exhaust. The filter has limited space, so the soot has to be burned off from time to time. This burning is called regeneration. A little ash is left over from the soot, and regeneration cannot remove ash. - **By itself, on the open road:** When you drive for a long time on a motorway or fast road, the exhaust is hot enough for the soot to burn off by itself. You don't notice anything. - **The computer starts it when the filter fills up:** A sensor tells the engine computer how full the filter is. The computer then injects a little more fuel to make the exhaust hotter. On many cars this happens roughly every 500 km and takes 5 to 10 minutes of driving. - **Forced regeneration with a diagnostic tool:** When the filter is too full to clean itself while driving, we start a regeneration through the car's computer with a diagnostic tool. ## When the DPF light is on The light means the filter has filled with soot or there is a fault in the filter system. Driving then usually cleans the filter, without stopping. **How long and how fast to drive depends on the car** - **Most often:** about 10 minutes faster than 65 km/h. - **Some cars:** 15 minutes at 70 km/h or more. - **Some cars:** 25 minutes above 60 km/h. - The exact procedure is in the car's manual. If the light doesn't go off after such a drive, turns red, flashes or the engine light comes on too, don't wait. A filter that is filling up can be fully blocked soon after. A blocked filter is protected by the car cutting engine power, and then even fast driving no longer helps. The sooner the filter is cleaned by regeneration, the smaller the chance it has to be replaced. [More about car diagnostics](https://autoindustrija.rs/en/services/car-diagnostics) ## How to tell that a regeneration is running While the computer is cleaning the filter, you will notice some of these: - the engine sounds different from usual - the fans under the bonnet are running - the engine idles at higher revs - start-stop doesn't switch the engine off - a hot, acrid smell comes from the exhaust - the car uses a little more fuel If you can, don't switch the car off then. When the drive is cut short, the regeneration doesn't finish and the light stays on. [More about why start-stop doesn't switch the engine off](https://autoindustrija.rs/en/advice/start-stop-system) ## Why the filter fills up and regeneration doesn't work - **You only drive short distances in town:** The engine and exhaust don't get hot enough, and the regeneration doesn't have time to finish. This is the most common reason for a blocked filter. - **There is little fuel in the tank:** On many cars regeneration doesn't start when the tank is less than a quarter full. - **The oil isn't the one the manufacturer specifies:** A diesel with a DPF usually needs low-ash oil. The wrong oil blocks the filter sooner. - **A fault in the injection, the EGR valve or the filter sensor:** The engine then makes more soot than the filter can burn off, or the computer doesn't know how full the filter is. - **The computer has stored a fault:** A stored fault can prevent regeneration until it is repaired. - **On some Peugeots and Citroëns, the additive has run out:** These cars have a separate tank with a fluid that mixes with the fuel and helps the soot burn. When the fluid runs out, the filter blocks quickly. That is why after a forced regeneration we always look for the cause as well. If the cause remains, the filter fills up again. ## How to make the DPF last longer A well-maintained DPF often lasts more than 160,000 km, sometimes as long as the car. Do not drive for long with the DPF light on: the sooner the filter is cleaned, the smaller the chance of damage. ## Forced regeneration, cleaning or replacing the DPF When too much ash has built up, even a forced regeneration no longer cleans the filter. It is then removed and cleaned with a special process, or replaced with a new one. [More about DPF cleaning](https://autoindustrija.rs/en/services/dpf-cleaning) ## Frequently asked questions ### Does a fuel additive clean the DPF? It doesn't remove ash, and ash is what regeneration can't burn off. An additive the car maker hasn't approved can even damage the filter. When the light won't go off, the car needs a check. Have a question about your car? Message us on WhatsApp or call 067 774 1606. ## Read also - [Car dashboard warning lights: meaning and when to stop](https://autoindustrija.rs/en/advice/dashboard-warning-lights) - [Check engine light (engine warning light): what it means and what to do](https://autoindustrija.rs/en/advice/check-engine-light) - [Car won't start: what to check first](https://autoindustrija.rs/en/advice/car-wont-start) --- Page on the website: https://autoindustrija.rs/en/advice/dpf-regeneration auto-industrija, Belgrade. Phone and WhatsApp: +381677741606. E-mail: kontakt@autoindustrija.rs.