Is a DPF delete legal? The UK rules on DPF removal
No, a DPF delete is not legal on a vehicle used on UK roads. If a car or van left the factory with a diesel particulate filter, it has to keep a working one, and it will fail the MOT without it. A delete is only an option for vehicles kept off the road or being exported.
What the law says
The Road Vehicles (Construction and Use) Regulations 1986 require emissions equipment to be kept in good working order. Using a vehicle on the road after its DPF has been taken out or switched off in software breaks those rules, however well it runs.
The DVSA has said the fines for using a vehicle with its DPF removed can reach £1,000 for a car and £2,500 for a light goods vehicle such as a van.
How the MOT checks for a DPF
MOT testers have checked for a missing DPF since February 2014, and the rules were tightened in May 2018. These are the points a diesel with a filter fitted as standard is tested on.
- A DPF that was fitted when the vehicle was made must still be there
- Emissions equipment fitted by the manufacturer that's missing, obviously modified or obviously defective is a major fault
- Evidence that the DPF has been tampered with is a major fault, and a filter that has been cut open and rewelded is rejected unless there's proof it was opened for cleaning
- A diesel with a DPF must show no visible smoke during the metered smoke test
- On diesels first used from 1 July 2008, an engine management light showing a fault is a major fault
When a DPF delete is allowed
A delete is legal on a vehicle that won't be used on a public road in the UK. We carry out DPF deletes for these uses only.
Track and competition cars
Vehicles used only on circuits, in motorsport or at private events, and transported to them rather than used on the road.
Off-road vehicles on private land
Farm, site and private-land vehicles that never go on the public highway.
Vehicles being exported
Cars and vans leaving the UK. The rules of the destination country then apply, so check them before booking.
If there's any chance the vehicle will be used on a UK road, a delete isn't the right choice.
Insurance and selling on
Any change to the emissions system is a modification your insurer needs to know about. The DVSA has warned that undeclared illegal modifications could invalidate a vehicle's insurance, which could leave you paying for a claim yourself.
If you buy a used diesel, check the MOT history and ask whether any DPF work has been done. A filter that has been emptied or switched off may not show on a quick look.
Legal fixes for a road vehicle
For a car or van that stays on the road, a blocked or failing DPF has to be fixed rather than removed. Here's the usual order we'd suggest.
Find out why it's blocking
A diagnostic check (£100 + VAT) reads the codes, soot load and pressure readings.
Fix the underlying fault
Sensors, EGR valves and injectors are common culprits.
Clean the filter
Our mobile DPF clean (£275 + VAT) clears soot with the filter still fitted.
Replace it if it's beyond cleaning
Ash-filled or cracked filters need a new unit, fitted by a garage.
Can an MOT tester tell if the DPF has been deleted?
Testers look for a missing filter, signs of cutting and welding, smoke during the emissions test and the engine management light. A delete can be missed, but the vehicle is still illegal to use on the road and the risk of a fine remains.
Will a DPF delete fail the MOT?
A missing filter, a tampered housing, visible smoke or a lit engine management light are all major faults, so a deleted diesel is very likely to fail. Passing by chance wouldn't make it road legal.
Do I have to tell my insurer about a DPF delete?
Yes. It's a modification to the emissions system, and insurers expect modifications to be declared. Not telling them risks your cover.
Is clearing a DPF on the motorway legal?
Yes. A steady run at legal motorway speeds is the normal way a DPF regenerates, and it's often what the handbook recommends when the light first appears. See DPF regeneration and forced regens.
Keep your diesel legal with a DPF clean
For a road vehicle, a clean is the legal fix for a soot-blocked filter. We'll do it at your home or workplace for £275 + VAT, with the original DPF left in place.
Is the vehicle staying off the road or going abroad? We carry out a DPF delete for £220 + VAT, strictly for off-road and export use only. Email sales@sgrautomotive.co.uk with any questions.
Eccles, Manchester M30 0SF