DPF Issues

Welcome to DPF Issues.

This site is aiming to become a key resource for Diesel particulate filters on a wide range of Diesel cars. Over the coming weeks a database will be setup that includes each make and model of car that contains a DPF filter. We then hope to track which models have frequent issues and which benefit from DPF removal.

Just what are the issues with a DPF filter?

If you use your modern Diesel car for short journeys in and about town the filter does not warm up sufficiently to burn off the soot that is caught in the filter, the filter must reach temperatures of 350-500oC to fully burn off the soot. Overtime if you consistently do short trips in your Diesel car the filter will become blocked. Usually a long trip every week or so will clear out the filter by means of “passive regeneration”

What happens when the DPF filter is blocked?

When the DPF filter reaches about 45% blockage the filter will begin “active regeneration” this means that the EGR (Exhaust gas Recirculation) valve is closed, the boost pressure from the turbo is increased slightly along with a slightly higher idle RPM. Diesel is then injected into the cylinders just after combustion so that it enters the Exhaust further heating up the DPF to around 600c and clearing the soot from the filter.

If however you switch off the engine before the DPF has been cleared you will get a DPF warning light on your dash. Read here to find out What to do if a DPF light is on the dash.

What if i ignore the light?

If you ignore the DPF light eventually the filter will reach a higher level of soot than is safe and could cause a fire risk. At this level the glow plug or engine warning light will also appear on your dash and you are advised to take your car to a dealership to force a “active regeneration”