What Is a Diesel Particulate Filter (DPF)?
The Diesel Particulate Filter is a ceramic honeycomb device mounted in the exhaust system of diesel vehicles. It traps soot and particulate matter from the exhaust gases before they are released into the atmosphere. The filter periodically cleans itself through a process called regeneration — either passive regeneration during sustained motorway driving, or active regeneration where the ECU injects extra fuel to raise exhaust temperatures and burn off the accumulated soot.
What Does the Diesel Particulate Filter (DPF) Do?
DPFs reduce the harmful particulate emissions from diesel combustion, which are linked to respiratory disease and environmental damage. They are mandatory on all diesel passenger cars manufactured in the EU since 2009 and are tested at MOT. A removed or bypassed DPF is an automatic MOT failure and is illegal on UK roads. DPFs typically last 100,000 miles or more when the vehicle is used appropriately.
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Get My Free Fault Scan →Symptoms of a Failing Diesel Particulate Filter (DPF)
A blocked DPF triggers a warning light on the dashboard and can cause the vehicle to enter limp mode with significantly reduced power. Increased fuel consumption is an early sign. The filter cannot regenerate if the vehicle is predominantly used for short, low-speed journeys. Professional forced regeneration or cleaning can restore a blocked DPF in many cases before full replacement is required.
When Should the Diesel Particulate Filter (DPF) Be Replaced?
DPFs are not routine replacement items — they should last the life of the vehicle with correct use. When replacement is necessary, cost ranges from £800 to over £2,000 depending on the vehicle. Professional DPF cleaning costs £150 to £400 and can be effective on moderately blocked filters.
If you are experiencing symptoms related to your diesel particulate filter (dpf) and are unsure whether it needs replacing, a free MotorLoom fault scan can help identify whether the component is likely at fault - giving you the most likely cause and estimated repair cost before you visit a garage.
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Related Parts
Other components that work alongside or are related to the diesel particulate filter (dpf):