Diesel Particulate Filters: ignorance is not bliss

Everything drivers need to know about Diesel Particulate Filters & how costly damage can be easily avoided.

Get the answers to all your DPF questions from regeneration to warning lights: find out what a DPF is, how regeneration works and manufacturer warranty exclusions.


What is a Diesel Particulate Filter?

Most modern diesel vehicles are fitted with a Diesel Particulate Filter (DPF) which removes soot from exhaust gases. The DPF reduces exhaust smoke and soot, significantly lowering emissions.


How does a Diesel Particulate Filter work?

The Diesel Particulate Filter will trap soot until a predetermined level is reached. It will then clean itself by heating up and burning off the accumulated soot particles. This process is known as DPF Regeneration. To do this, the DPF needs a high exhaust temperature.

Under most driving conditions the vehicle will achieve DPF Regeneration unaided. However, in some circumstances - usually due to frequent short journeys - it can’t reach the required temperature, in which case the driver is normally alerted by a warning light in the instrument panel. (This varies between vehicle make and model.)


What to do if a Diesel Particulate Filter warning light comes on.

A Diesel Particulate Filter warning light typically looks like one of these symbols:

Diesel Particulate Filter troubleshooting warning light
Diesel Particulate Filter troubleshooting warning light

If a DPF warning is displayed, the vehicle is notifying the driver that the DPF needs assistance to achieve its Regeneration. To do this, simply drive for 10-15 minutes keeping a steady engine speed of around 2,500rpm. A hop on a nearby motorway for a few junctions would do the trick.

If a driver does not take action, the DPF warning light will remain lit and additional DPF symbols relating to soot levels and/or a DPF blockage may also appear:

Diesel Particulate Filter troubleshooting warning light
Diesel Particulate Filter troubleshooting warning light

 If this happens, immediate attention is required by an authorised repairer.

If a DPF warning is ignored and the vehicle continues to be driven in the same manner, it is likely that the filter and/or the engine will be damaged irreversibly.


DPFs & your manufacturer warranty.

If a DPF is damaged as a result of a driver ignoring a DPF warning light, the costly work to replace it is not likely to be covered by any manufacturer warranty or maintenance contract as it would be classified as lack of care/negligence.

In short, DPF damage is avoidable. Take heed of DPF regeneration warning lights on your dash and regularly take your car for a nippy drive to kick off it's self-cleaning. Job's a good 'un.


Get your free Diesel Particulate Filter fact sheet.

We've talked through DPF working, warnings, warranties. Hopefully it's been helpful. Now share the love with your diesel driving buddies with this one page DPF fact sheet:

Diesel Particulate Filters | DPF regeneration, tanks and warranty

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