# SCR vs DPF | explained > SCR vs DPF: SCR and a DPF are two separate systems on the same exhaust. The DPF traps soot particles and burns them off. SCR… - URL: https://adblueinfuel.co.uk/explained/scr-vs-dpf/ - Focus: scr vs dpf - Updated: 2026-09-22 - Phone: 01295 380724 (From just £89 call-out fee) - Publisher: AdBlue in Fuel — a service by Forecourt Assist — Forecourt Assist is a trading name of Fuel Fixer Ltd, company no 08520551, registered at Fairway House, Portland Road, East Grinstead, RH19 4ET, a company of Fuel Fixer International. --- ## SCR vs DPF Short answerSCR vs DPF — sCR and a DPF are two separate systems on the same exhaust. The DPF traps soot particles and burns them off. SCR uses AdBlue to convert NOx into nitrogen and water. A DPF problem is not an AdBlue problem. Call 01295 380724 From just £89 call-out fee Written by Rambo S, Wrong Fuel Expert at Fuel Fixer International. ## SCR vs DPF — the detail ### What a DPF does The diesel particulate filter is a mechanical trap. Soot collects in it and is periodically burnt off in a regeneration cycle, which needs heat and therefore needs a decent run. A blocked DPF is a soot problem, and it is solved with heat, not with fluid. ### What SCR does Selective catalytic reduction is chemistry, not filtration. A metering pump and a dosing injector spray AdBlue into the hot exhaust stream ahead of the catalyst. The urea decomposes to ammonia, and the ammonia reacts with nitrogen oxides across the catalyst to produce nitrogen and water. ### Why they get confused Both sit in the exhaust, both illuminate a warning lamp, and both can put a vehicle into reduced power. The failure modes and the fixes have almost nothing in common. Topping up AdBlue will not clear a blocked DPF, and a long motorway run will not fix a failed dosing injector. ### How to tell which you are dealing with Read the message rather than the lamp. DPF messages talk about a filter, a regeneration or a long drive. AdBlue messages name the fluid, give a remaining range, or count down to a no-restart. If a countdown to no restart is showing, that is SCR. ### Do they interact? They sit in the same exhaust and a vehicle can have faults in both, but they are separate systems with separate components, separate sensors and separate faults. ## Common questions ### Will a long drive fix an AdBlue fault? No. That is DPF advice. A DPF regeneration needs sustained heat; an SCR fault needs fluid, a working dosing circuit and a functioning catalyst. ### Does AdBlue clean the DPF? No. AdBlue is dosed downstream of the engine for NOx reduction and has nothing to do with trapping or burning soot. ### Can a blocked DPF cause an AdBlue warning? They are separate faults, but a vehicle with sustained exhaust problems can log codes in both systems. The codes, not the lamp, tell you which. £89 is the call-out. An AdBlue tank drain and flush is quoted on the phone before a technician travels. If the SCR system needs component replacement — dosing injector, pump, tank or catalyst — that is separate, and you will be told before any work starts. If this is a job we cannot fix at the roadside, we will tell you that on the phone rather than after we arrive. ### More explainers ISO 22241Driver inducementWhat AdBlue actually isHow much AdBlue a vehicle usesAdBlue storage and shelf life ### If something has already gone wrong AdBlue in dieselAdBlue in the diesel tankDiesel in the AdBlue tankPetrol in the AdBlue tankAdBlue warning lightAdBlue countdown and no restartAdBlue system faultAdBlue tank drainAdBlue system reset ## What customers say 4.8 out of 5 from 2,190 Trustpilot reviews. What reviewers mention most is that the technician stayed calm and professional with a driver who was embarrassed and stressed, and that somebody arrived when they said they would. The most common criticism is price. People do not expect a wrong-fluid job to cost what it costs, and that is a fair complaint to publish rather than bury. The answer is the From just £89 call-out fee, a quote given on the phone before a technician travels, and being told when a job cannot be done at the roadside rather than after somebody has arrived and charged for the visit. ## Who you are dealing with Work booked through AdBlue in Fuel is carried out by Fuel Fixer Ltd, company no 08520551, registered at Fairway House, Portland Road, East Grinstead, RH19 4ET, trading as Forecourt Assist and part of Fuel Fixer International, which is owned by Stockbridge Capital Holdings. Reference: Urea (Wikipedia). ## Across the Fuel Fixer network Diesel in PetrolFuel Doctor FleetFuel Fixer IrelandMisfuel DoctorAdBlue in Fuel is a service by Forecourt Assist, a brand of Fuel Fixer International, owned by Stockbridge Capital Holdings. The full group directory is at forecourtassist.co.uk/network.