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DPF
How to clean a DPF?
CheckFuelPrices Editorial
Expert Written • 4 industry sources
You can clean a partially blocked DPF by driving at sustained motorway speeds to trigger passive regeneration, burning off the accumulated soot. For more severe blockages, active regeneration, a DPF cleaning additive, or a professional garage clean may be required.
How a DPF Becomes Blocked
What a DPF does:
A diesel particulate filter traps soot particles from exhaust gases to reduce harmful emissions. Over time, soot accumulates and the filter needs to be cleared.
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Short journeys are the main cause:
Frequent short, low-speed trips prevent the exhaust from reaching the temperature needed to burn off soot naturally. This is the most common cause of DPF blockages in the UK.
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Warning light:
A DPF warning light on your dashboard means the filter is approaching capacity. Acting quickly at this stage can avoid a more expensive fix.
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Methods to Clean a Blocked DPF
Passive regeneration – motorway driving:
Drive at 60 mph or above for 20–30 minutes on a dual carriageway or motorway. This raises exhaust temperatures high enough to burn off the soot automatically, without any garage visit.
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Active regeneration:
If passive regen fails, your engine management system may trigger active regeneration by injecting extra fuel to raise exhaust temperature. Do not switch the engine off mid-journey during this process.
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DPF cleaning additives:
Fuel-based DPF cleaning additives can lower the soot combustion temperature, helping a partially blocked filter to regenerate. These are most effective when the filter is only mildly clogged.
Professional garage clean:
A severely blocked DPF that cannot regenerate will need to be removed and cleaned professionally, or replaced. Forced regeneration using diagnostic equipment is another option a garage can carry out.
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What You Must Not Do
Never remove the DPF:
Removing a DPF is illegal in the UK. A car with a missing or tampered DPF will fail its MOT and can result in a fine of up to £1,000 for cars.
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Do not ignore a blocked DPF:
Continuing to drive with a severely blocked DPF can cause the filter to crack, requiring full replacement at a cost of £1,000 or more.
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Preventing Future Blockages
Use the right diesel:
Low-quality or contaminated diesel can accelerate DPF clogging. Using fuel from a reputable station helps maintain filter health.
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Combine short trips where possible:
If your driving is mainly urban and short-distance, make a habit of a longer motorway run every few weeks to allow passive regeneration to occur naturally.
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Check fuel prices before filling up:
Using CheckFuelPrices to find the cheapest nearby diesel means you can fill up more often with quality fuel without overspending.
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Sources
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