Diesel Particulate Filter Removal (DPF)


At UD MOTOR X we specialize in all areas of vehicle remapping and tuning.

To complement our extensive performance, economy and C02 reduction tuning, UD MOTOR X also offer a range of Diesel Particulate Filter and DPF delete services.

In its standard form a vehicles Diesel Particulate Filter, or tdi dpf cycle can be troublesome for a range of reasons, to reduce driver inconvenience and costly repairs UD MOTOR X can tune or remove or delete DPF function allowing for improved reliability, servicing and performance.

Diesel Particulate Filter Warning Symbol Indicators

These are variants of Diesel Particulate Filter (DPF) Warning symbol indicators. The light will be green during DPF regeneration. An amber light means that regeneration is needed, which is done automatically while driving. A manual regeneration procedure may also be available. A red light indicates that the DPF requires regeneration immediately. The check engine or service engine soon light will come on and engine power will be reduced if the filter is not attended to.

This symbol indicates that the Diesel Exhaust Fluid (DEF) is low. The fluid creates a catalytic reaction that removes particles from the exhaust. When low, the fluid must be topped off. The fluid will need to be replaced if it is contaminated. Last one is another particle filter symbol. It may appear with an exclamation point in it indicating a failure of the system or that engine emissions are too high. Contact your dealer in order to properly address any failures. All of these odd looking images are meant to indicate exhaust flow through a pipe. Lots of wavy lines, pipe openings and what could even be interpreted as flames are used.


The exhaust emissions standards for new cars have effectively required fitment of a DPF in the exhaust of diesel cars since 2009 when the 'Euro 5' standard came into force. In fact, many cars registered before 2009 will have had one fitted too in anticipation of the change in standards.

Standards aim to deliver an 80% reduction in diesel particulate (soot) emissions but the technology's not without problems – AA patrols are regularly called to cars with the particulate filter warning light on indicating a partial blockage of the filter.

Even if your driving isn't mainly urban/stop-start, changes to driving style may be require to keep these systems working properly.

If you're buying a new car and plan to use it mainly for town-based, stop/start driving it would be wise to avoid a diesel car fitted with a Diesel Particulate Filter (DPF) because of thepossible hassle of incomplete 'DPF regeneration.

How do they work?

Diesel Particulate filters (DPF) or 'traps' do just that, they catch bits of soot in the exhaust.

As with any filter they have to be emptied regularly to maintain performance. For a DPF this process is called 'regeneration' – the collected soot is burnt off at high temperature to leave only a tiny ash residue.

Regeneration is either passive or active

Passive regeneration

Passive regeneration takes place automatically on motorway-type runs when the exhaust temperature is high. Because many cars don't get this sort of use car manufacturers have to design-in 'active' regeneration where the engine management computer (ECU) takes control of the process.

Active regeneration

When the soot loading in the filter reaches a set limit (about 45%) the ECU will initiate post combustion fuel injection to increase the exhaust temperature and trigger regeneration. If the journey is a bit stop/start or you take your foot off the accelerator while the regeneration is in progress, it may not complete and the warning light will come on to show that the filter is partially blocked.

It should be possible to start a complete regeneration and clear the warning light by driving for 10 minutes or so at speeds greater than 75 kmph.

If the regeneration is unsuccessful the extra fuel injected will not burn and will drain into the sump. Oil quality will deteriorate as a result of this and the level will rise. It is important that you check that the oil level does not increase above the maximum level on the dipstick as diesel engines can run on excess engine oil – often to the point of destruction.

If you ignore the warning light and keep driving in a relatively slow, stop/start pattern, soot loading will continue to build up until around 75% when you can expect to see other dashboard warning lights come on too. At this point driving at speed alone will not be enough and you will have to take the car to a dealer for regeneration.

Expensive repairs

If you continue to ignore warnings and soot loading keeps increasing then the car won’t run properly and the most likely outcome will be that you will have to get a new DPF costing at least Rs 65,000.

The ash residue which remains after successful regeneration cannot be removed and will eventually fill the filter. DPFs are designed to last about 75,000 KMs, but many, operating correctly, are achieving more than this.

DPF Additives

The most commonly fitted type of DPF has an integrated oxidising catalytic converter and is located very close to the engine where exhaust gases will still be hot. This heat means that passive regeneration is more likely to be successful.

Some models, across a wide range of manufacturers, use a different type of DPF which relies on a fuel additive to lower the ignition temperature of the soot particles.

The additive is stored in a separate tank next to the fuel tank and is automatically mixed with the fuel whenever you fill up. Only very small quantities are used so a litre of additive should treat around 2800 litres of fuel – enough to cover 40,000 KM at 17kmpl. It lasts about 75,000 KMs and is replenished during a service – at extra cost.

You will have to pay to get the additive tank refilled at some time in the car's life – expect to pay around Rs. 15,000/- including fluid and labour.
Don't be tempted to ignore a warning light showing that the additive tanks need refilling. It's absolutely essential this tank is refilled as without it regeneration is unlikely to be successful and a new DPF may be needed – at significant cost. Fuel consumption can increase as a result of failed regenerations too.


We're seeing some evidence of DPF systems failing to regenerate even on cars used mainly on motorways.
On cars with a very high sixth gear the engine revs may be too low to generate sufficient exhaust temperature for regeneration. Occasional harder driving in lower gears should be sufficient to burn off the soot in such cases.<>br/ DPF regeneration will be initiated by the ECU every 500 KMs or so depending on vehicle use and will take 5 to 10 minutes to complete. You shouldn't notice anything other than perhaps a puff of white smoke from the exhaust when the process is completed. There's no evidence in AA breakdown data that the problem's going away – newer car models seem just as likely to suffer DPF problems if not driven 'correctly' as those built when DPF's were introduced.

Check the handbook

If you buy a car with a DPF it’s important to read the relevant section of the vehicle handbook so that you understand exactly what actions to take if the warning light illuminates and how, if at all, your driving style may need to be adjusted to ensure maximum DPF efficiency and life.
In most cases there is only a relatively short time between the dpf being partially blocked and becoming so blocked that it requires manual regeneration.