What is a DPF and Why Does It Matter?

Many diesel vehicles have a Diesel Particulate Filter. (DPF). In this article, we explain what it is, why it is needed and why it needs to be serviced.


DPF stands for diesel particulate filter, and as the name suggests, it stops tiny diesel particles (otherwise known as soot) that are emitted from your vehicle’s exhaust. If certain precautions are not adhered to, the way DPF’s work can create problems. 



What is a DPF Filter?

Diesel engines burn fuel a lot differently than gas engines. Soot is created as a result of the combustion process. This ultra-fine, nearly invisible material can cause serious environmental issues, it’s the DPF’s job to catch and destroy them before this happens.


DPF’s were standardized in 2009, but some vehicles had this technology before then. 


DPF Regeneration

While a DPF’s primary purpose is to trap and hold on to damaging particulates, it also needs to get rid of them. In a process called regeneration, the DPF exposes them to extremely high temperatures, burns them and turns them into harmless ash. 




How do I get my filter cleaned?

DPF Regeneration and Why Diesels Can Be Bad for Short Trips

The DPF can start regeneration in a couple of ways, but both need the exhaust gases to get extremely hot – usually around 500 degrees Celsius, which is twice as hot as a regular oven. ‘Passive regeneration’ takes place when you drive your car at speeds above 40mph for several minutes at a time, and doing this regularly should burn off the particulates in the DPF automatically.

Drivers who only drive short distances, won’t get their exhaust to a high enough temperature for ‘passive regeneration’ to happen. This can create a soot build-up, eventually blocking the DPF and creating engine problems such as misfiring and reduced fuel-efficiency. You may also see a warning light on the dashboard.

If you don’t regularly drive at a high speed, the engine will try to clear the DPF via ‘active regeneration’. This is where the after treatment system causes the exhaust gases to get hot enough to burn off the soot without requiring the car to be run at speed.


Unfortunately, active regeneration can only take place when the vehicle is moving, so anyone who does not do much highway driving may find their vehicles are unable to actively regenerate the DPF. 


Most vehicles have a two-stage warning system. An amber light means you should be able to get the DPF to regenerate itself by driving over 40mph for about 10 minutes. However, if you see a red DPF warning light, however, this means a trip to the garage is needed. 

If the DPF light comes on, it’s time to get device cleaned.


You will need to get your DPF cleaned as soon as possible. While you can buy DPF cleaner fluids from automotive stores, these are not proven to be effective. It is best to leave DPF cleaning to the professionals. 

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