A diesel particulate filter (DPF) is a great auto filter that captures and stores exhaust soot to reduce emissions from diesel cars. But because they only have a finite capacity, this trapped soot periodically has to be emptied or ‘burned off’ to regenerate the DPF.

This regeneration process burns off the excess soot deposited in the filter, reducing the harmful exhaust emission and helps to prevent the tell-tale black smoke you used to see from diesel vehicles, particularly when accelerating.

So when can you say your DPF has been blocked?

So how can you tell if your filter is blocked? Typically, when the filter becomes clogged or an error occurs in the system, an orange light will appear on your dashboard. This light varies based on the manufacturer, but commonly appears similar to the image below. When this lights up, you know your filter is most likely blocked, and regeneration may be required.

Just like there are two main particulates being filtered, there are two types of cleanings that are required. Regeneration cleans out the soot by converting the carbon to carbon dioxide, and the ash is removed by removing the filter and cleaning it in a machine with compressed air.

The best way to maintain a DPF is to make sure it’s fully able to regenerate itself when it’s full of soot. It’s what we recommend here at DCARB.

There are two types of regeneration: passive and active. Let’s get to know them!

Passive regeneration occurs when your vehicle is running at speed on long motorway journeys which allow the exhaust temperature to increase to a higher level and cleanly burn off the excess soot in the filter.

At DCARB, we advise that drivers regularly give their diesel vehicles a good 30 to 50 minute run at sustained speed on a motorway or A-road to help clear the filter. However, not all drivers do this type of driving regularly– which is why manufacturers have designed an alternative form of regeneration. One of which is Redline.

Active regeneration means extra fuel is injected automatically, as part of the vehicle’s ECU, when a filter reaches a predetermined limit to raise the temperature of the exhaust and burn off the stored soot.

Problems can occur, however, if the journey is too short, as the regeneration process may not complete fully. If this is the case the warning light will continue to show the filter is still partially blocked.

In which case it should be possible to complete a regeneration cycle and clear the warning light by driving for 10 minutes or so at speeds greater than 40mph.

Yes and no. Ideally, yes because your DPF needs cleaning services from time to time. And No because you don’t need to do it by yourself— we have professionals for that.

Cleaning your DPF requires professional work and expertise. Trust professionals who will take good care in finding issues on your DPF and addressing these problems accordingly, providing you with reliable and long-lasting solutions.

If you want to know more about DPFs, talk with our experts at DPF Cleaning and DCARB today!