{
    "name": "AdBlue and SCR contamination severity matrix",
    "description": "Every AdBlue and SCR contamination scenario covered by this site, with the direction of contamination, the severity verdict (recoverable, likely recoverable or component risk), whether it is work performed by Forecourt Assist or a garage referral, the typical cost band in pounds sterling and the typical minutes on site. The severity verdict is deterministic: it follows from the direction of contamination and whether the engine was started, and the same inputs always return the same verdict.",
    "version": "2026.10",
    "date_modified": "2026-10-13",
    "geography": "United Kingdom",
    "temporal_coverage": "2026/..",
    "publisher": {
        "name": "Fuel Fixer Ltd",
        "operator": "Forecourt Assist",
        "url": "https://adblueinfuel.co.uk/"
    },
    "license": "https://creativecommons.org/licenses/by/4.0/",
    "canonical_url": "https://adblueinfuel.co.uk/services/",
    "cite_as": "AdBlue in Fuel, AdBlue and SCR contamination severity matrix, v2026.10, https://adblueinfuel.co.uk/data/severity-matrix",
    "distribution": [
        "https://adblueinfuel.co.uk/data/severity-matrix.csv",
        "https://adblueinfuel.co.uk/data/severity-matrix.json",
        "https://adblueinfuel.co.uk/data/severity-matrix.parquet",
        "https://adblueinfuel.co.uk/data/severity-matrix/croissant.json"
    ],
    "variables": [
        {
            "name": "slug",
            "type": "Text",
            "description": "Stable identifier, also the URL path segment"
        },
        {
            "name": "problem",
            "type": "Text",
            "description": "Human-readable name"
        },
        {
            "name": "direction",
            "type": "Text",
            "description": "adblue-in (into a fuel tank) | into-adblue | system"
        },
        {
            "name": "severity",
            "type": "Text",
            "description": "recoverable | likely-recoverable | component-risk"
        },
        {
            "name": "verdict",
            "type": "Text",
            "description": "The verdict in one sentence"
        },
        {
            "name": "serviced",
            "type": "Text",
            "description": "yes = attended by this operator; no = garage referral"
        },
        {
            "name": "cost_low_gbp",
            "type": "Integer",
            "description": "Lower bound of the typical cost band, GBP"
        },
        {
            "name": "cost_high_gbp",
            "type": "Integer",
            "description": "Upper bound of the typical cost band, GBP"
        },
        {
            "name": "minutes_on_site",
            "type": "Integer",
            "description": "Typical technician time on site"
        },
        {
            "name": "url",
            "type": "URL",
            "description": "Canonical page"
        }
    ],
    "row_count": 34,
    "rows": [
        {
            "slug": "adblue-in-diesel",
            "problem": "AdBlue in diesel",
            "direction": "adblue-in",
            "severity": "recoverable",
            "verdict": "Normally put right by a drain and flush, provided the engine has not been run.",
            "serviced": "yes",
            "cost_low_gbp": 200,
            "cost_high_gbp": 420,
            "minutes_on_site": 60,
            "url": "https://adblueinfuel.co.uk/adblue-in-diesel/"
        },
        {
            "slug": "adblue-in-the-diesel-tank",
            "problem": "AdBlue in the diesel tank",
            "direction": "adblue-in",
            "severity": "recoverable",
            "verdict": "Normally put right by a drain and flush, provided the engine has not been run.",
            "serviced": "yes",
            "cost_low_gbp": 200,
            "cost_high_gbp": 450,
            "minutes_on_site": 65,
            "url": "https://adblueinfuel.co.uk/adblue-in-the-diesel-tank/"
        },
        {
            "slug": "adblue-in-petrol",
            "problem": "AdBlue in petrol",
            "direction": "adblue-in",
            "severity": "recoverable",
            "verdict": "Normally put right by a drain and flush, provided the engine has not been run.",
            "serviced": "yes",
            "cost_low_gbp": 190,
            "cost_high_gbp": 400,
            "minutes_on_site": 60,
            "url": "https://adblueinfuel.co.uk/adblue-in-petrol/"
        },
        {
            "slug": "adblue-in-the-petrol-tank",
            "problem": "AdBlue in the petrol tank",
            "direction": "adblue-in",
            "severity": "recoverable",
            "verdict": "Normally put right by a drain and flush, provided the engine has not been run.",
            "serviced": "yes",
            "cost_low_gbp": 190,
            "cost_high_gbp": 420,
            "minutes_on_site": 60,
            "url": "https://adblueinfuel.co.uk/adblue-in-the-petrol-tank/"
        },
        {
            "slug": "adblue-in-the-screen-wash-tank",
            "problem": "AdBlue in the screen wash tank",
            "direction": "adblue-in",
            "severity": "recoverable",
            "verdict": "Normally put right by a drain and flush, provided the engine has not been run.",
            "serviced": "yes",
            "cost_low_gbp": 89,
            "cost_high_gbp": 160,
            "minutes_on_site": 30,
            "url": "https://adblueinfuel.co.uk/adblue-in-the-screen-wash-tank/"
        },
        {
            "slug": "adblue-in-the-engine-oil",
            "problem": "AdBlue in the engine oil",
            "direction": "adblue-in",
            "severity": "component-risk",
            "verdict": "Frequently needs SCR component work rather than a drain. Quoted before a technician travels.",
            "serviced": "no",
            "cost_low_gbp": 260,
            "cost_high_gbp": 600,
            "minutes_on_site": 90,
            "url": "https://adblueinfuel.co.uk/adblue-in-the-engine-oil/"
        },
        {
            "slug": "adblue-in-the-coolant-tank",
            "problem": "AdBlue in the coolant tank",
            "direction": "adblue-in",
            "severity": "component-risk",
            "verdict": "Frequently needs SCR component work rather than a drain. Quoted before a technician travels.",
            "serviced": "no",
            "cost_low_gbp": 240,
            "cost_high_gbp": 520,
            "minutes_on_site": 90,
            "url": "https://adblueinfuel.co.uk/adblue-in-the-coolant-tank/"
        },
        {
            "slug": "adblue-spilled-on-paintwork",
            "problem": "AdBlue spilled on paintwork",
            "direction": "adblue-in",
            "severity": "recoverable",
            "verdict": "Normally put right by a drain and flush, provided the engine has not been run.",
            "serviced": "no",
            "cost_low_gbp": 89,
            "cost_high_gbp": 180,
            "minutes_on_site": 30,
            "url": "https://adblueinfuel.co.uk/adblue-spilled-on-paintwork/"
        },
        {
            "slug": "adblue-in-the-wrong-filler",
            "problem": "AdBlue in the wrong filler",
            "direction": "adblue-in",
            "severity": "recoverable",
            "verdict": "Normally put right by a drain and flush, provided the engine has not been run.",
            "serviced": "yes",
            "cost_low_gbp": 89,
            "cost_high_gbp": 450,
            "minutes_on_site": 60,
            "url": "https://adblueinfuel.co.uk/adblue-in-the-wrong-filler/"
        },
        {
            "slug": "diesel-in-the-adblue-tank",
            "problem": "Diesel in the AdBlue tank",
            "direction": "into-adblue",
            "severity": "component-risk",
            "verdict": "Frequently needs SCR component work rather than a drain. Quoted before a technician travels.",
            "serviced": "yes",
            "cost_low_gbp": 260,
            "cost_high_gbp": 750,
            "minutes_on_site": 90,
            "url": "https://adblueinfuel.co.uk/diesel-in-the-adblue-tank/"
        },
        {
            "slug": "petrol-in-the-adblue-tank",
            "problem": "Petrol in the AdBlue tank",
            "direction": "into-adblue",
            "severity": "component-risk",
            "verdict": "Frequently needs SCR component work rather than a drain. Quoted before a technician travels.",
            "serviced": "yes",
            "cost_low_gbp": 280,
            "cost_high_gbp": 850,
            "minutes_on_site": 100,
            "url": "https://adblueinfuel.co.uk/petrol-in-the-adblue-tank/"
        },
        {
            "slug": "screen-wash-in-the-adblue-tank",
            "problem": "Screen wash in the AdBlue tank",
            "direction": "into-adblue",
            "severity": "likely-recoverable",
            "verdict": "Usually resolved by a drain and flush, with a fluid-quality check afterwards.",
            "serviced": "yes",
            "cost_low_gbp": 180,
            "cost_high_gbp": 380,
            "minutes_on_site": 70,
            "url": "https://adblueinfuel.co.uk/screen-wash-in-the-adblue-tank/"
        },
        {
            "slug": "water-in-the-adblue-tank",
            "problem": "Water in the AdBlue tank",
            "direction": "into-adblue",
            "severity": "likely-recoverable",
            "verdict": "Usually resolved by a drain and flush, with a fluid-quality check afterwards.",
            "serviced": "yes",
            "cost_low_gbp": 170,
            "cost_high_gbp": 360,
            "minutes_on_site": 60,
            "url": "https://adblueinfuel.co.uk/water-in-the-adblue-tank/"
        },
        {
            "slug": "tap-water-in-the-adblue-tank",
            "problem": "Tap water in the AdBlue tank",
            "direction": "into-adblue",
            "severity": "likely-recoverable",
            "verdict": "Usually resolved by a drain and flush, with a fluid-quality check afterwards.",
            "serviced": "yes",
            "cost_low_gbp": 190,
            "cost_high_gbp": 420,
            "minutes_on_site": 70,
            "url": "https://adblueinfuel.co.uk/tap-water-in-the-adblue-tank/"
        },
        {
            "slug": "oil-in-the-adblue-tank",
            "problem": "Oil in the AdBlue tank",
            "direction": "into-adblue",
            "severity": "component-risk",
            "verdict": "Frequently needs SCR component work rather than a drain. Quoted before a technician travels.",
            "serviced": "yes",
            "cost_low_gbp": 300,
            "cost_high_gbp": 900,
            "minutes_on_site": 110,
            "url": "https://adblueinfuel.co.uk/oil-in-the-adblue-tank/"
        },
        {
            "slug": "coolant-in-the-adblue-tank",
            "problem": "Coolant in the AdBlue tank",
            "direction": "into-adblue",
            "severity": "component-risk",
            "verdict": "Frequently needs SCR component work rather than a drain. Quoted before a technician travels.",
            "serviced": "yes",
            "cost_low_gbp": 280,
            "cost_high_gbp": 780,
            "minutes_on_site": 100,
            "url": "https://adblueinfuel.co.uk/coolant-in-the-adblue-tank/"
        },
        {
            "slug": "wrong-adblue-non-iso-22241",
            "problem": "Wrong AdBlue — non ISO 22241 fluid",
            "direction": "into-adblue",
            "severity": "likely-recoverable",
            "verdict": "Usually resolved by a drain and flush, with a fluid-quality check afterwards.",
            "serviced": "yes",
            "cost_low_gbp": 180,
            "cost_high_gbp": 420,
            "minutes_on_site": 70,
            "url": "https://adblueinfuel.co.uk/wrong-adblue-non-iso-22241/"
        },
        {
            "slug": "contaminated-adblue",
            "problem": "Contaminated AdBlue",
            "direction": "into-adblue",
            "severity": "likely-recoverable",
            "verdict": "Usually resolved by a drain and flush, with a fluid-quality check afterwards.",
            "serviced": "yes",
            "cost_low_gbp": 170,
            "cost_high_gbp": 400,
            "minutes_on_site": 65,
            "url": "https://adblueinfuel.co.uk/contaminated-adblue/"
        },
        {
            "slug": "expired-adblue",
            "problem": "Expired AdBlue",
            "direction": "into-adblue",
            "severity": "recoverable",
            "verdict": "Normally put right by a drain and flush, provided the engine has not been run.",
            "serviced": "yes",
            "cost_low_gbp": 150,
            "cost_high_gbp": 330,
            "minutes_on_site": 55,
            "url": "https://adblueinfuel.co.uk/expired-adblue/"
        },
        {
            "slug": "overfilled-adblue-tank",
            "problem": "Overfilled AdBlue tank",
            "direction": "into-adblue",
            "severity": "recoverable",
            "verdict": "Normally put right by a drain and flush, provided the engine has not been run.",
            "serviced": "yes",
            "cost_low_gbp": 89,
            "cost_high_gbp": 220,
            "minutes_on_site": 40,
            "url": "https://adblueinfuel.co.uk/overfilled-adblue-tank/"
        },
        {
            "slug": "adblue-warning-light",
            "problem": "AdBlue warning light",
            "direction": "system",
            "severity": "recoverable",
            "verdict": "Normally put right by a drain and flush, provided the engine has not been run.",
            "serviced": "no",
            "cost_low_gbp": 89,
            "cost_high_gbp": 300,
            "minutes_on_site": 50,
            "url": "https://adblueinfuel.co.uk/adblue-warning-light/"
        },
        {
            "slug": "adblue-countdown-no-restart",
            "problem": "AdBlue countdown and no restart",
            "direction": "system",
            "severity": "likely-recoverable",
            "verdict": "Usually resolved by a drain and flush, with a fluid-quality check afterwards.",
            "serviced": "no",
            "cost_low_gbp": 140,
            "cost_high_gbp": 420,
            "minutes_on_site": 60,
            "url": "https://adblueinfuel.co.uk/adblue-countdown-no-restart/"
        },
        {
            "slug": "adblue-limp-mode",
            "problem": "AdBlue limp mode",
            "direction": "system",
            "severity": "likely-recoverable",
            "verdict": "Usually resolved by a drain and flush, with a fluid-quality check afterwards.",
            "serviced": "no",
            "cost_low_gbp": 140,
            "cost_high_gbp": 450,
            "minutes_on_site": 65,
            "url": "https://adblueinfuel.co.uk/adblue-limp-mode/"
        },
        {
            "slug": "adblue-system-fault",
            "problem": "AdBlue system fault",
            "direction": "system",
            "severity": "likely-recoverable",
            "verdict": "Usually resolved by a drain and flush, with a fluid-quality check afterwards.",
            "serviced": "no",
            "cost_low_gbp": 89,
            "cost_high_gbp": 400,
            "minutes_on_site": 60,
            "url": "https://adblueinfuel.co.uk/adblue-system-fault/"
        },
        {
            "slug": "adblue-crystallisation",
            "problem": "AdBlue crystallisation",
            "direction": "system",
            "severity": "likely-recoverable",
            "verdict": "Usually resolved by a drain and flush, with a fluid-quality check afterwards.",
            "serviced": "no",
            "cost_low_gbp": 150,
            "cost_high_gbp": 480,
            "minutes_on_site": 70,
            "url": "https://adblueinfuel.co.uk/adblue-crystallisation/"
        },
        {
            "slug": "adblue-tank-drain",
            "problem": "AdBlue tank drain",
            "direction": "system",
            "severity": "likely-recoverable",
            "verdict": "Usually resolved by a drain and flush, with a fluid-quality check afterwards.",
            "serviced": "yes",
            "cost_low_gbp": 180,
            "cost_high_gbp": 480,
            "minutes_on_site": 75,
            "url": "https://adblueinfuel.co.uk/adblue-tank-drain/"
        },
        {
            "slug": "adblue-system-flush",
            "problem": "AdBlue system flush",
            "direction": "system",
            "severity": "likely-recoverable",
            "verdict": "Usually resolved by a drain and flush, with a fluid-quality check afterwards.",
            "serviced": "yes",
            "cost_low_gbp": 220,
            "cost_high_gbp": 520,
            "minutes_on_site": 90,
            "url": "https://adblueinfuel.co.uk/adblue-system-flush/"
        },
        {
            "slug": "adblue-injector-blocked",
            "problem": "Blocked AdBlue injector",
            "direction": "system",
            "severity": "component-risk",
            "verdict": "Frequently needs SCR component work rather than a drain. Quoted before a technician travels.",
            "serviced": "no",
            "cost_low_gbp": 180,
            "cost_high_gbp": 650,
            "minutes_on_site": 90,
            "url": "https://adblueinfuel.co.uk/adblue-injector-blocked/"
        },
        {
            "slug": "adblue-pump-failure",
            "problem": "AdBlue pump failure",
            "direction": "system",
            "severity": "component-risk",
            "verdict": "Frequently needs SCR component work rather than a drain. Quoted before a technician travels.",
            "serviced": "no",
            "cost_low_gbp": 220,
            "cost_high_gbp": 850,
            "minutes_on_site": 100,
            "url": "https://adblueinfuel.co.uk/adblue-pump-failure/"
        },
        {
            "slug": "frozen-adblue",
            "problem": "Frozen AdBlue",
            "direction": "system",
            "severity": "recoverable",
            "verdict": "Normally put right by a drain and flush, provided the engine has not been run.",
            "serviced": "no",
            "cost_low_gbp": 120,
            "cost_high_gbp": 420,
            "minutes_on_site": 60,
            "url": "https://adblueinfuel.co.uk/frozen-adblue/"
        },
        {
            "slug": "nox-sensor-fault",
            "problem": "NOx sensor fault",
            "direction": "system",
            "severity": "component-risk",
            "verdict": "Frequently needs SCR component work rather than a drain. Quoted before a technician travels.",
            "serviced": "no",
            "cost_low_gbp": 160,
            "cost_high_gbp": 600,
            "minutes_on_site": 75,
            "url": "https://adblueinfuel.co.uk/nox-sensor-fault/"
        },
        {
            "slug": "scr-catalyst-damage",
            "problem": "SCR catalyst damage",
            "direction": "system",
            "severity": "component-risk",
            "verdict": "Frequently needs SCR component work rather than a drain. Quoted before a technician travels.",
            "serviced": "no",
            "cost_low_gbp": 200,
            "cost_high_gbp": 900,
            "minutes_on_site": 90,
            "url": "https://adblueinfuel.co.uk/scr-catalyst-damage/"
        },
        {
            "slug": "adblue-system-reset",
            "problem": "AdBlue system reset",
            "direction": "system",
            "severity": "likely-recoverable",
            "verdict": "Usually resolved by a drain and flush, with a fluid-quality check afterwards.",
            "serviced": "no",
            "cost_low_gbp": 100,
            "cost_high_gbp": 300,
            "minutes_on_site": 45,
            "url": "https://adblueinfuel.co.uk/adblue-system-reset/"
        },
        {
            "slug": "adblue-level-sensor-fault",
            "problem": "AdBlue level sensor fault",
            "direction": "system",
            "severity": "likely-recoverable",
            "verdict": "Usually resolved by a drain and flush, with a fluid-quality check afterwards.",
            "serviced": "no",
            "cost_low_gbp": 140,
            "cost_high_gbp": 550,
            "minutes_on_site": 70,
            "url": "https://adblueinfuel.co.uk/adblue-level-sensor-fault/"
        }
    ]
}