How to Clear a Blocked DPF Filter

A blocked DPF filter can cause a host of potential issues, clearing a blocked DPF using these 3 methods will keep your exhaust and engine healthy.

A Diesel Particle Filter (DPF) will become blocked from a build-up of soot inside the filter. Eventually, if the exhaust does not get hot enough, this soot can build up to a dangerous level, hindering the performance of the car, potentially causing damage to engine components.

Clearing a DPF will increase exhaust airflow, performance and reliability as the vehicle will be able to ‘breathe’ freely.

DPF diagnostics

Passive Regeneration

This is the most common method of clearing a DPF and your diesel vehicle will be doing it all the time without you realising. On longer journeys, the exhaust naturally get hots enough to burn off the soot inside the exhaust. However, this is not the most effective method and if you do not drive your diesel vehicle on the motorway often, it’s inconvenient.

If you have mostly driven your diesel car around town and notice that the DPF is becoming blocked, take the car out on a long, motorway journey in an attempt to burn off the soot. On the motorway or dual carriageway, use a gear down (5-speed use 4th and 6-speed use 5th) to increase the engine revs. An engine regeneration will not occur if the fuel tank is lower than one quarter, and any other engine faults that may occur will stop the regeneration process.

Active Regeneration

Active regeneration is triggered by the vehicles ECU and increases the amount of fuel being burnt by the engine, this is to increase the temperature inside the DPF and burn off the soot.

This process can be noticed by a higher idle RPM, smoke from the exhaust and on some models, a warning message. Do not turn off the engine until the regeneration process has completed as this will interrupt the process and allow the DPF to cool down, meaning the soot will not be burnt off and the DPF will become more blocked.

Our DPF regeneration service will tell your car to enter the active regeneration process to burn away the build-up of soot. This is one of the cheapest and most convenient methods to somewhat effectively clear a blockage inside the DPF

Dpf filter

DPF Cleaning

DPF cleaning is the most effective way to clear a blocked DPF filter. Flash cleaning a blocked DPF will completely remove the build-up of soot and exhaust residue, ensuring increased performance and economy.

Flash cleaning your DPF completely removes PM10 residues, oil and cerium. A flash clean ensures the safety of the DPF so no damages can occur during the process.

Another DPF cleaning solution is to use a heat method. This heats up the DPF so that the Soot can naturally burn off once it has reached a high enough temperature. However, this has some drawbacks; there is a risk of damaging the integrity of the filter due to cutting and welding, melting the cerium of the filter walls due to high temperature, and risk of thermal shock to noble metals.

Ultrasonic DPF cleaning treatments are affective at deeply cleaning the filter cells, removing soot and residue buildup. However, ultrasonic treatment poses a risk of damage to the filter from the vibrations and has a poor efficiency on very dirty and larger filters

Chemical additives are a cheap and easy cleaning solution but are often ineffective at cleaning the DPF as residues are not eliminated and more residues are created by the chemicals themselves, further blocking the DPF.

So, a flash clean is the best possible way to clear a blocked DPF. This method has no drawbacks and will make the DPF perform like new. Increasing the vehicles performance, fuel economy, emissions and overall health. Suitable for all vehicle types a flash clean is great for heavy-duty diesel vehicles such as lorries and buses, but also ideal for cars and vans.

Speak to an expert

Got concerns about your DPF? Whether it’s a repair, a replacement or just some advice about your filter, we can help. Get in touch with us using the form below, drop us an email or give us a call on 0114 3490923. We look forward to hearing from you.


0114 3490 923


Unit 3, The Gables
Holywell Road
Sheffield, South Yorkshire
S4 8AR