Diesel Particulate Filter (DPF) Faults

We have the solution for blocked DPF's & coked up intake systems. BG Complete Air Intake and Emissions System Service.

The BG Air Intake and Emissions System Service cleans from the air intake, right through the engine to the DPF..

Other options only tackle the symptom of the blocked DPF itself. BG’s DPF & Emissions Cleaning System attacks the real problem - poor combustion and the consequence, soot build-up.

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.

Removing the DPF & then remapping the vehicle to delete the regeneration mode is now illegal.

We investigate the issue before we go ahead with any cleaning. There are a number of reasons why the vehicle has a blocked DPF & hasn't gone into regeneration mode as it should.

Your Options Explained

The advantage of our machine is clear when you see the alternative options.

Option 1: Buy a new DPF. This can be very expensive. In some cases this can be way out of most peoples budget.

Option 2: Remove the DPF & send it off to a company that cleans them. The disadvantage of this is the labour to remove & fit the DPF & the time the vehicle is off the road waiting for the DPF to be sent away & returned. The other disadvantage to this is that it will only be the DPF itself that has been cleaned. The intake system could still be coked up & cause more issues.

Option 3: Book the vehicle in with us for a BG Air Intake & Emissions System Service. We run a full diagnostic check on the vehicle to establish the reason the DPF is blocked. We inform you of any issues with faulty components like glow plugs, egr valve or anything that has failed. Once any faults are rectified we then fit the machine to the vehicle & perform the clean cycle. We then add a BG109 to the engine oil which cleans the inside of the engine. This cleans any hard carbon deposits around the piston rings & restores compression. We then change the engine oil & filter & add a BGDOC which is an oil conditioner. This helps to keep the inside of the engine cleaner. We also add a BG244 which cleans the entire fuel system.

In most cases if we have the vehicle at 09:00 you can have your vehicle back the same day.

Is your DPF light on?

What to do

If the dashboard DPF warning light illuminates while the performance of the vehicle appears normal this usually indicates that you need to manually regenerate the filter.

If the ECU detects that the filter is fully blocked it will not allow the regeneration process to proceed for safety reasons. At this point the DPF warning light on the dashboard will come on and the car will go into 'limp' mode to prevent further damage. If this happens call us.

Preventative Maintenance

We can inspect various components. Clean & de-coke if necessary. We can run our machine on a diesel vehicle to clean out the intake system even if the vehicle does not have a DPF. Some vehicles do get very restricted intake manifolds & cylinder head ports due to carbon build up.

What is a DPF?

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.

Removal is not a legal option.

It is suggested from time to time that the answer to failed DPF regeneration is get the DPF removed from the exhaust system rather than pay to get it repaired/renewed. Indeed there are companies advertising just such a service including reprogramming of the engine management software, but is it legal?

DPFs are fitted to meet European emissions regulations designed to reduce vehicle emissions of particulate matter (soot) associated with respiratory disease and cancer.

According to the Department for Transport, it is an offence under the Road vehicles (Construction and Use) Regulations (Regulation 61a(3)) to use a vehicle which has been modified in such a way that it no longer complies with the air pollutant emissions standards it was designed to meet. Removal of a DPF will almost invariably contravene these requirements, making the vehicle illegal for road use.


You must notify your insurer if the vehicle is modified but such a modification could in turn invalidate any insurance cover because it makes the vehicle illegal for road use.


From February 2014 the inspection of the exhaust system carried out during the MOT test will include a check for the presence of a DPF. A missing DPF, where one was fitted when the vehicle was built, will result in an MOT failure.

With an original equipment DPF removed from the exhaust the car may or may not pass an MOT smoke test - a Euro V (September 2009 diesel) is more likely to fail than one designed to comply with earlier emissions standards.

save money on fuel

Ask us about the MPG Service.

We recommend this MPG improvement service.

Cleans Fuel System.

Combusted fuel leaves deposits in fuel systems. The most critical component is the injector. Deposits interfere with proper spray pattern. This service will clean the entire fuel system & restore atomized spray pattern in the injector.

Restores Engine Compression.

Compression is vital to power & Economy. As a vehicle's piston moves it squeezes a fuel/air mixture in the cylinder, giving it explosive power. Rings around each piston ensure a good seal. Loss of compression is usually due to deposits restricting these rings.

The BG Compression Restoration Flush will clean deposits from the rings, restoring peak compression, ensuring maximum Power & Efficiency.

The link above will soon give you more info about BG Products.