What is a Diesel particulate filter?
Diesel particulate filters or DPF’s have been fitted to many diesel vehicles exhaust systems over the last few years. Manufacturers fit this device as part of their compliance with ‘Euro 5′ emission standards.
DPF’s act as a soot trap within the exhaust system and can reduce the vehicles emissions by up to 80%. As you are driving around urban areas, particles of soot are trapped within the DPF, thus cutting emissions within our towns and cities. The soot then sits within the filter waiting to be emptied. The process of emptying the DPF is referred to as ‘regeneration’. Regeneration of the particle filter occurs automatically when the exhaust is hot, such as when driving on a motorway at speeds of over 50mph. On this type of journey, the soot trapped in the DPF is burnt off leaving only a tiny amount of ash in the filter.
Urban driving and DPF’s
If you own a diesel engined car fitted with a DPF and are mainly using your vehicle for driving around town or stop-start runs, then you may run into DPF problems. The AA advise ‘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 the possible hassle of incomplete ‘DPF regeneration’.’
If you do own this type of vehicle, we would suggest you take time to schedule a monthly motorway run into your diary. This small step can help to avoid expensive repairs down the line. The vehicle needs to travel at a sustained speed with high revs, so a 20 mile trip travelling above 50 mph will help the DPF to regenerate.
Oh no! The DPF warning light has come on the dash.
If full regeneration of the DPF has not taken place for a while then first, the vehicles ECU will step in and try to control the problem. If the ECU cannot force regeneration by changing the way the car runs then a dash warning light will appear.
DO NOT ignore this warning
If you have been doing regular motorway type runs and the light has appeared, it could indicate other problems with your vehicle. You should go and check with your local mechanic for the cause of the warning light. If the light has only just come on and you have been using the car for urban driving, you could try going for a motorway run to clear the filter. If successful the DPF will regenerate & the light will go off. This should help to prevent the soot load building up again. If the warning light remains on, get the car into your local garage to be checked out.
I ignored the light, oops
If you ignore the warning light and carry on driving around at low urban speeds then soot in the DPF will continue to build. More warnings will probably appear on your dash and a motorway run will no longer be enough to clear the DPF. You now need to take the vehicle into your local garage for repair. If the DPF filter needs to be replaced this could well cost you over £1000. In some cases, the filter can be cleaned out without needing to be replaced. We would suggest obtaining advice from several garages, as often what one mechanic says needs replacing, the next mechanic may well be able to repair.
Back Home Performance are always happy to offer advice and give no-obligation quotations.
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