Passive, active and forced regeneration
Our DPF regeneration guide explains the process in more detail, including the signs that an active regeneration is running.
Passive
Happens naturally when exhaust temperatures are high enough, typically during sustained faster driving.
Active
The engine control unit raises exhaust temperature, often by adjusting injection, to burn off soot when it calculates the filter needs it. Interrupting it — by switching off mid-regeneration on short trips — is a common cause of build-up.
Forced
Started with diagnostic equipment, usually with the vehicle stationary and monitored. It is a tool, not a cure, and it is not suitable for every filter.
When a forced regeneration is — and is not — appropriate
If soot loading is moderate and there is no fault preventing regeneration, a forced regen can help. If soot loading is very high, a forced regeneration can generate excessive heat and risk damaging the filter, and many systems will refuse to start one. If ash loading is high, regeneration cannot help because ash does not burn.
Faults that stop regeneration — sensor failures, EGR problems, low fuel level conditions on some vehicles, or certain other warnings — need fixing first. We check those conditions before attempting a forced regeneration.
How we approach DPF regeneration
Diagnosis comes before parts or software. We read stored fault codes, look at live data such as sensor readings, temperatures and pressures where the system makes them available, and ask how and when the problem appears. A warning light describes a symptom that the control unit has detected; it does not always name the part that has failed, so the fault code is the starting point of the investigation rather than the answer.
Once we understand the likely cause we explain the findings in plain language and discuss the sensible options, which might be a repair, a clean, a software update, a replacement part or simply a change in how the vehicle is used. You receive a quote for the agreed scope before further work goes ahead. We will not recommend removing an emissions system as a fix for a road vehicle.
What to send us before booking DPF regeneration
The quickest way to get useful advice is to send the registration and a short description by WhatsApp or through the quote form. Support and suitability vary by engine, gearbox, control unit and software version, so a registration lets us check the right information instead of guessing. Any estimate given remotely is provisional until the vehicle has been seen and the required checks are complete.
- 01Vehicle registration and approximate mileage
- 02Make, model and engine size, if known
- 03Any warning lights, messages, symptoms or fault codes
- 04Existing remaps, tuning boxes or hardware modifications
- 05How the vehicle is used — commuting, towing, short trips or heavy loads
- 06Whether the vehicle is currently in limp mode or will not start
Emissions equipment and the law
We do not offer DPF, EGR or AdBlue/SCR deletes for vehicles intended for public-road use. Removing or disabling emissions controls can make road use unlawful, and a missing factory-fitted DPF is an MOT failure. An “off-road” disclaimer does not make a road vehicle compliant. Non-road enquiries are considered only where the intended use can be verified, and are assessed individually against the applicable requirements.
Read the government guidance on diesel particulate filters ↗
Visiting the workshop for DPF regeneration
All work is carried out at our single workshop at Unit 2, Lancaster Works, Kingsbridge Road, Manchester M9 5SP. We do not run a mobile remapping service and we have no other branches, so every DPF regeneration enquiry is booked into the same Manchester workshop. Visits are by arrangement: please call or WhatsApp before travelling so we can confirm the vehicle, the time and what the visit will involve.
Access is through the black gate. Call when you arrive so we can let you in, then keep left towards the rear of the site. We are open Monday to Friday 8am–6pm and Saturday 8am–1pm, and closed on Sunday. If the vehicle is in limp mode, showing a serious warning or will not start, tell us before setting off so we can talk about whether it is sensible to drive it or whether transport should be arranged.