DPF compliance: a practical checklist for garages and fleet managers

Diesel particulate filter (DPF) rules are not new, but they are about to get much tougher. A Department for Transport (DfT) consultation that closed on 6 September 2026 proposes making it an offence to run any vehicle whose emissions system no longer meets the standard it was built to, whether through tampering or simple poor maintenance. Here is what applies now, what is changing, and the practical steps to have in place.

What is changing

The loophole is being closed. The current in-use emissions rule (regulation 61A of the Construction and Use Regulations 1986) was never updated beyond Euro 4 and Euro V. In practice there is no ongoing legal duty to keep the emissions systems of Euro 5/6 cars and vans, or Euro VI lorries, working. (DfT consultation)

What the DfT proposes:

  • Every vehicle first used from 1 January 2001 must keep its emissions control systems working to the standard set when it was built. (consultation: Our proposal)
  • Enforcement through existing Road Traffic Act 1988 offences: section 42 (using a non-compliant vehicle), section 75 (alterations) and section 76 (fitting or supplying unsuitable parts). Fines run from £1,000 to unlimited.
  • It would be an offence to use such a vehicle, to allow it to be used, or to modify it. That brings vehicle owners, fleet operators and workshops into scope.
  • No distinction between poor maintenance and deliberate modification, between intended and unintended effects, or between hardware and software (remap) changes.
  • Named as always illegal: DPF or GPF removal, catalytic converter removal, AdBlue/SCR delete and EGR manipulation. (consultation: Vehicle modifications)
  • Timeline: legislation expected summer 2027, with a proposed six-month lead-in for owners to get servicing done and for businesses to change their activities and advertising. DVSA will enforce, focusing first on businesses carrying out illegal modifications. (consultation: Proposed timelines)

The government response has not yet been published, so details may change. The direction is clear, though.

What already applies today

  • MOT (cars and vans): a DPF fitted by the manufacturer that is missing, obviously modified or defective is a major fault, as is any evidence of tampering. A DPF that has clearly been cut open and re-welded is rejected unless the presenter can show a valid reason, such as cleaning. Any visible smoke from a DPF-equipped vehicle during the metered test is a major fault, and so is an engine warning light that is on. Vehicles first used from 2014 are tested to 0.7m⁻¹ or the lower plate value. (MOT inspection manual, section 8.2.2)
  • MOT testers: DVSA has warned that testers who overlook a missing DPF, or take part in removals, face serious consequences. (DVSA Matters of Testing blog)
  • HGVs at the roadside: since September 2018 DVSA has routinely checked lorries for emissions cheat devices. Drivers get 10 days to repair, then face a £300 fine and prohibition, and operators can be referred to the Traffic Commissioner. (DVSA news)
  • Operator licence holders must have satisfactory arrangements to keep vehicles fit and serviceable, and remain responsible even when maintenance is outsourced. (DVSA Guide to maintaining roadworthiness)
  • Better testing is coming: DfT has said the current smoke test is not effective at spotting missing or failed DPFs and is trialling particle number (PN) testing. (DfT consultation response, 2024)

Practical steps for garages and workshops

  1. Stop all delete work now. That includes DPF, EGR and AdBlue removal and remaps that disable them. Check your website, listings and adverts for any reference to it.
  2. Find the root cause. A blocked DPF is usually a symptom. Check sensors, EGR, injectors, turbo, thermostat and service history before cleaning or replacing.
  3. Document every DPF job. Keep diagnostic reports from before and after. If a filter has been opened for cleaning, give the customer written evidence for their MOT.
  4. Fit approved parts only. Supplying or fitting an unsuitable replacement DPF is already an offence under section 76.
  5. Pre-MOT checks: warning lights, fault codes, visible smoke and the plate smoke value.
  6. Brief your team, including MOT testers, on what the proposed changes mean for advice given to customers.

Practical steps for fleet managers

  1. Audit the fleet. Confirm every DPF, SCR and EGR system is present and working, especially on second-hand, hired or recently acquired vehicles. Under the proposals, allowing a non-compliant vehicle to be used would be an offence.
  2. Make DPF warnings a defect. Add them to drivers’ daily checks and defect reports, and act promptly. Ignoring a warning light leads to limp mode or the vehicle stopping, and a far costlier fix.
  3. Schedule preventative cleaning. Plan for every 20,000 miles or 24 months, sooner for urban LCVs, and by engine hours for HGVs.
  4. Keep the paper trail. Diagnostic reports and cleaning records show you have maintained the emissions system.
  5. Check your suppliers. Make sure maintenance providers do not offer delete services. Your operator licence is on the line, not theirs.
  6. Use the lead-in period. Budget now for any filters that need cleaning or replacing before enforcement begins.

How DPF Fixer can help

Clean where suitable, replace where necessary. Every clean includes diagnostics before and after, and you keep the reports, which make a ready-made compliance record. We also look at the root cause so the problem does not come straight back. Work is covered by a 30-day warranty, with nationwide mobile service, off-car factory cleaning and replacement options.

Speak to our team on 0333 366 1461, or send us your vehicle details for an assessment.