Dpf what is

Petrol or diesel: should I buy a diesel? Most cars have a two-stage warning system. If you see an amber light, you should be able to get the DPF to regenerate itself by driving over 40mph for about 10 minutes. If you see a red DPF warning light, however, this means you need to pull over to the side of the road and phone your breakdown company to take you to the garage. You can check our helpful guide to dashboard warning lights here.

Shopping around for an aftermarket DPF could save you some money, however. If your car requires an oil with a low ash content, that can also signify that it has a DPF. All VW Group 1.

While there are plenty of unscrupulous individuals offering a DPF delete or removal, doing so will only end badly. One final word of caution: if you own a diesel car, make sure you know how to get your DPF to regenerate, so you can do it as soon as you see the warning light come on.

And, if you frequently turn off the engine while the DPF is going through the regeneration cycle, it can lead to severe engine damage. Why do diesel emissions matter? Our article on the evolution of diesel and emissions explains all.

Many modern diesel cars also come with AdBlue , so read our guide for all you need to know. Towing with an electric car, hybrid or plug-in hybrid - what's the capacity and can you tow a caravan? Skip to header Skip to main content Skip to footer. Doing this on a regular basis is enough to burn off the soot and turn it to ash. However, it requires the temperatures created when a car is running at speed for a sustained period of time.

To make sure that the regeneration takes place, it's advised that diesels are driven for a good 30 to 45 minutes on a motorway or A-road at a constant speed. However, passive generation isn't always possible, for instance if you sit in lots of traffic. So car manufacturers have designed active regeneration. Active regeneration works by injecting extra fuel in order to increase the the temperature of the exhaust gases and burn off the soot in the DPF.

It still requires a journey of a reasonable length though - around 10 minutes at 40mph or more is the suggested time. When the DPF is regenerating you may notice the the cooling fans running and higher fuel consumption.

The tell tale sign for many is a hot and unusual smell from under the car. The engine idle speed can also be higher than usual. If your car has start-stop, you'll likely find that it's deactivated during regeneration. Going for a minute motorway drive is a fail-safe way of keeping your DPF filter in good condition, but there are some other tricks. One of those is making sure your car isn't always running on an empty fuel tank. DPFs get clogged with soot if regeneration doesn't happen often enough.

If that's the case you'll get a DPF warning light come up on the dash. Cars with active regeneration should see fewer DPF problems. You need to ensure your DPF regenerates in order to stop it clogging up with soot. That means driving it a sustained speed for 30 minutes or more.

How often you should do this depends on the kind of driving you're doing but if you sit in a lot of traffic, a good motorway or dual-carriageway run at 60mph once a week will burn it off. Active regeneration will be initiated every miles or so depending on how you use your car and will take around 5 to 10 minutes to complete. If your DPF becomes clogged with soot, you will get a warning light on your dash. Driving at a sustained speed in order to burn the excess soot off is often enough to clean the DPF and solve the problem without needing to visit a garage.

But if you ignore this warning light, the car will eventually go into limp mode to prevent further engine damage. You should also ensure you use the right engine oil. Certain oils contain additives that can actually block DPFs. Using low-quality fuel and running the car frequently on a low fuel level can also harm a DPF because the car may avoid regeneration in order to save fuel.

This filter is designed to capture and trap exhaust soot and other nasty particles created by the diesel fuel combustion process and prevent them from being pumped out into the atmosphere during city driving. The DPF is an important component and necessary for diesel vehicles to meet emissions regulations. The regeneration process can only happen when the DPF reaches a temperature capable of burning away the soot particles.

This happens in one of two ways. When driven at speed for a reasonable period — on a decent highway journey, for example — the temperature becomes high enough for the passive regeneration burn to take place. If you are buying a used diesel then be sure to check if this has been carried out by a previous owner.

Having said that, unless the car's emissions are affected, it's hard for an MoT test station to detect whether a DPF has been removed.

These take out the filters and remount the empty housing, so it looks like the DPF is fitted as normal. And because the MoT only requires a visual inspection that all emissions kit is present, the MoT tester would be none the wiser. Have you had any problems with DPFs that we should know about?

Let us know in the comments below. Brand loyalty evaporates as car demand hits all-time high. Skip to Content Skip to Footer. What is a DPF?