How to Clean Diesel Exhaust Filters

by Natalie Lyda

Diesel particulate filters, or DPFs, help regulate diesel emissions in an effort to meet standards set by the Environmental Protection Agency. Diesel particulate filters usually are placed in the outgoing exhaust flow pipe. Disposable DPFs, normally used only in off-road applications such as heavy equipment, are discarded once they have been filled with particulates. Reusable, passive regenerating diesel particulate filters will clean themselves, while active filters may be cleaned quickly and easily.


Refer to the owner's manual to learn which type of diesel particulate filter is in your vehicle. Passive regeneration filters require no effort on the part of the vehicle owner to clean, while active regeneration filters may need temporary driving adjustments to help clean the filter.


Check the dashboard to confirm that the diesel particulate filter warning light is on. Typically, driving at slow speeds or in stop-and-go conditions for a long time will trigger this light, which indicates that the exhaust gas has not been hot enough to effectively burn off particulate matter trapped in the filter. Clogged diesel particulate filters may cause poor vehicle performance and will need to be taken to the dealership for professional servicing if a simple cleaning is not performed.


To conduct a simple cleaning, drive the vehicle to a highway or other high-speed roadway. Accelerate until the vehicle reaches speeds in excess of 40 miles per hour. Continue to drive the vehicle at speeds above 40 mph for at least 10 minutes, which will raise the exhaust gas temperature to a point that will clear any particulate matter trapped in the filter. Watch for the warning light to turn off, indicating that the diesel particulate filter has been cleaned.

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