Replacement catalytic converters and DPFs are legally controlled parts in the UK. If your vehicle was first registered on or after 1 March 2001, a replacement catalytic converter must be type approved for it, and if it is Euro 5 or later, so must a replacement DPF1. This guide explains what type approval means, which vehicles the law covers and how to tell whether a part qualifies.
What type approval means
Type approval is certification by a government approval authority that a replacement part meets the legal standard for the vehicles it is approved for. In the UK that authority is the Vehicle Certification Agency (VCA)2. For a replacement catalytic converter or DPF, the approval tests compare its emissions with the original part on the same vehicle, and cover its durability and its compatibility with the vehicle’s on-board diagnostics3.
An approval covers a list of specific vehicles, with their years of manufacture3. That matters more than people expect: parts for different vehicles, approved to different Euro levels, can share the same housing and pipework yet differ inside, in their approval and in how they perform. A part that can be made to fit is not necessarily approved, or legal, for your vehicle and its Euro level4.
What the law requires
- Catalytic converters: for a vehicle first registered on or after 1 March 2001, a replacement catalytic converter must be type approved for that vehicle. It is illegal to supply one that is not1. The rule covers passenger vehicles and light vans that were fitted with a catalytic converter when new5.
- DPFs: for a vehicle that is Euro 5 or later, a replacement DPF must be type approved. Euro 5 applies to vehicles registered from 1 January 2011, although some Euro 5 vehicles were registered before that date1.
- Who is responsible: the offence is committed by a business that supplies or fits a non-approved part where an approved one is required. “Supply” includes offering or displaying a part for sale5.
- Penalties: the government’s guidance gives the fine as up to £5,0001. The regulations set it at level 5 on the standard scale5, which has been an unlimited fine in England and Wales since 12 March 2015 and remains £5,000 in Scotland and Northern Ireland6.
Vehicles first registered before 1 March 2001 are outside the type-approval rule, which is why some catalytic converters for older vehicles have no approval.
Separately, removing a DPF almost always makes a vehicle illegal to use on the road, and a vehicle built with a DPF fails its MOT without one1,7.
How to tell whether a part is approved
- The approval mark. A replacement catalytic converter or DPF approved for a Euro 5 or Euro 6 vehicle carries an approval mark: a lower-case “e” in a rectangle, followed by the number of the country that granted the approval (11 is the United Kingdom) and the approval number3.
- The vehicle list. An approved part comes with the list of vehicles it is approved for3. If yours is not on it, the part is not approved for your vehicle.
- The certificate. If you are not sure, the government’s advice is to ask the manufacturer or distributor for a copy of the type-approval certificate1.
- In our range, approved parts have an H at the end of the part number (for homologated, the industry term for type approved) and are marked Type Approved on the product page (see BM Catalysts part numbers explained).
A note on “sports cats” and de-cat pipes
High-flow “sports” catalytic converters and de-cat pipes sold “for off-road use” are generally not type approved for road vehicles. On a petrol vehicle first used from 1 September 2002, emission control equipment that is missing or obviously modified is a major defect, so the vehicle fails its MOT8. And using a vehicle on the road when it no longer meets its emission limits because its exhaust has been altered is an offence9.
Where our parts stand
The parts we sell are manufactured by BM Catalysts, Europe’s leading independent manufacturer of aftermarket “hot end” emissions parts. In our range today:
- every DPF listed for a Euro 5 vehicle is type approved;
- every combined catalytic converter and DPF, catalytic converter and GPF and SCR and DPF unit is type approved.
Each product page lists the vehicles, years and Euro level the part is catalogued for: check them against your vehicle’s own standard, using our Euro emissions standards guide. Browse type-approved catalytic converters or find your vehicle.
Sources
- Department for Transport, “Catalytic converters and diesel particulate filters” (updated 30 May 2023). gov.uk
- Vehicle Certification Agency. gov.uk
- Commission Regulation (EC) No 692/2008, Annex XIII (type approval of replacement pollution control devices). legislation.gov.uk
- BM Catalysts, “The importance of Euro level compliance”. bmcats.com
- The Motor Vehicles (Replacement of Catalytic Converters and Pollution Control Devices) Regulations 2009 (SI 2009/1899), regulations 2 to 7 and the Schedule. legislation.gov.uk
- Legal Aid, Sentencing and Punishment of Offenders Act 2012, section 85; Criminal Procedure (Scotland) Act 1995, section 225; Fines and Penalties (Northern Ireland) Order 1984, article 5. legislation.gov.uk
- Department for Transport, “Diesel particulate filters: guidance note”. gov.uk
- DVSA, MOT inspection manual for private passenger and light commercial vehicles, section 8.2.1. gov.uk
- The Road Vehicles (Construction and Use) Regulations 1986, regulation 61A. legislation.gov.uk