SCR catalyst damage
SCR catalyst damage is the expensive end of AdBlue contamination — the washcoat poisoned by what was dosed through it. It cannot be flushed out. Call 01293 248666 for an assessment before anyone quotes a catalyst.
The SCR catalyst converts NOx to nitrogen and water using the ammonia that AdBlue decomposes into. Its active surface is a washcoat, and hydrocarbons, metal impurities and oil residue poison it permanently — they do not wash off and they do not burn off. This is the single reason not starting the engine after contaminating the AdBlue tank matters so much: an unrun system has a clean catalyst, and a catalyst is the most expensive component in the chain.
Call 01293 248666 From just £89 call-out fee
This is not a drain job, so it is not work we do. AdBlue in Fuel drains and flushes AdBlue contamination — AdBlue put into a fuel tank, or diesel, petrol, water, screenwash or oil put into the AdBlue tank. That is the whole service. SCR catalyst damage is an SCR system fault, and it is fixed by a garage or a franchised dealer with the right diagnostic tooling, not by draining a tank at the roadside.
The page below is here because the question gets asked constantly and the answers online are poor. It is reference material, not a sales page. There is no call-out price quoted for it, because we would not be the ones attending. If you are not certain which of the two you are looking at, call 01293 248666 and describe it — if it is a drain we will quote it, and if it is not we will say so and you will not be charged for the conversation.
SCR catalyst damage — the severity verdict
| Severity | Component risk Frequently needs SCR component work rather than a drain. Quoted before a technician travels. |
|---|---|
| What this is | SCR catalyst damage — an SCR system fault, not a contaminated tank |
| Who fixes it | A garage or franchised dealer with SCR diagnostic tooling |
| Do we do it? | No. AdBlue in Fuel drains AdBlue contamination only |
| Typical cost | £200–£900 at a garage — a guide figure, not our quote |
| If you are unsure | 01293 248666 — we will tell you which of the two it is |
What to do right now
- Establish whether the system actually dosed after the contamination — that is the question that decides this.
- Do not let anyone quote a catalyst from a fault code alone.
- Call 01293 248666.
What a technician actually does
Conversion efficiency measured from live upstream and downstream NOx data with the dosing system verified as working, so that catalyst condition is established rather than assumed. Replacement, where genuinely needed, is quoted with the numbers before anything is ordered.
Why this is not the same job as the other direction
This is an SCR system fault rather than a wrong fill, so the first job is reading the codes rather than guessing at a part. The same dashboard message covers a bottle of fluid and a catalyst.
Common questions
Can a poisoned SCR catalyst be cleaned?
Hydrocarbon and metal poisoning of the washcoat is not reversible by cleaning. Thermal regeneration deals with soot in a DPF, which is a different component and a different problem.
How do I know the catalyst is actually damaged?
By measuring conversion with a known-good dosing system. A conversion fault with a blocked injector is an injector problem, and replacing a catalyst will not fix it.
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.
Related AdBlue problems
Start from a symptom instead
Who you are dealing with
This site is published by Forecourt Assist, which operates AdBlue in Fuel. 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. The group, Fuel Fixer International, is owned by Stockbridge Capital Holdings.
Reference: GOV.UK — vehicle approval.
Across the Fuel Fixer network
AdBlue 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.