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Problems with AdBlue: symptoms, cost and affected models

We have documented 18 faults with AdBlue in 18 engines, affecting 130 models of car in our database. The most important by severity and frequency: AdBlue tank and pump failure (1.5 BlueHDi), AdBlue tank and pump fault (1.6 BlueHDi) (1.6 HDi) and AdBlue tank crystallisation and failures (BlueHDi) (2.0 HDi). At an independent garage, the repair costs from €100 to €2,000 depending on the engine or car.[1][2][3]

Documented faults
18
0 of high or critical severity
Engines
18
with at least one fault on this part
Affected models
130
car generations in our database
Garage repair
€100–€2,000
Depending on engine and car, including VAT

18 sourcesHow we work

How it works and why it fails

AdBlue (SCR) system and NOx sensor

The latest Euro 6 diesels reduce nitrogen oxides with an SCR catalyst that needs AdBlue, a urea solution injected into the exhaust. The AdBlue tank, pump, heater and injector, together with the NOx sensors, are expensive parts and some of them tend to crystallise or fail.

What to do

If the AdBlue warning appears with a countdown in kilometres, do not push it: when it reaches zero, the car will not start again. Top up with certified AdBlue, do not mix it with water and ask about the manufacturer's campaigns or extended warranties before paying for a complete tank.

General explanation by MotorFiable. The specific faults of each engine and car, with their sources, are on the linked pages.

Common symptoms

The symptoms that come up most often in the documented faults with AdBlue. Open each one to see what other faults cause it.

Problems with AdBlue by engine

From most to least important (severity × frequency). Each page details the affected versions and years, symptoms, cost and how to check for it.

  1. 1Medium severityVery frequentFrequency: Very frequent1.5 BlueHDiAdBlue tank and pump failure1.5 BlueHDi engines built up to August 2020 can suffer failures of the AdBlue tank pump module, with a "no engine start" countdown. The whole tank is usually replaced and Stellantis contributes to the cost up to 8 years.Repair: €1,000–€1,500
  2. 2Medium severityVery frequentFrequency: Very frequent1.6 HDiAdBlue tank and pump fault (1.6 BlueHDi)The 1.6 BlueHDi engines (2013-2019) suffer from the AdBlue tank defect of Stellantis diesels: an emissions warning appears with a countdown until starting is prevented. Replacing the tank, with the integrated pump, costs over €1,000 (price in Spain), but there is an extended warranty of up to 8 years.Repair: €1,000–€1,200
  3. 3Medium severityVery frequentFrequency: Very frequent2.0 HDiAdBlue tank crystallisation and failures (BlueHDi)On the 2.0 BlueHDi with SCR and AdBlue (from 2013), the system's tank, pump or sensors can fail or crystallise: a warning light appears, sometimes a false one, and if ignored the car may end up not starting. The OCU has reported it in Spain and Stellantis compensates some of those affected.Repair (garage): €800–€1,200
  4. 4Medium severityVery frequentFrequency: Very frequentOM642Emissions defeat device (AdBlue/EGR) and software update campaignGermany's KBA found indications of emissions manipulation in cars with the OM642 engine (alongside the OM651): AdBlue dosing and the EGR changed between the test bench and the road. Mercedes-Benz denied it, but in 2018 it recalled hundreds of thousands of diesels in Europe.
  5. 5Medium severityVery frequentFrequency: Very frequent2.0 BlueHDiAdBlue (SCR) tank and pump failureOn the 2.0 BlueHDi, the AdBlue tank can crystallise or fail and show a warning with a countdown to the point where the engine will not start. It is the most frequently cited fault of this engine: Stellantis compensates owners of diesels built up to August 2020, with no definitive fix.Repair: €1,000–€1,500
  6. 6Medium severityCommonFrequency: CommonBMW N43/N46Injector, ignition coil and NOx sensor failures (N43)On the direct-injection BMW N43, failures of the injectors, ignition coils (mainly in 2007-2008 units, now rare after a BMW service action) and the NOx sensor of its lean-burn combustion have been documented. The indirect-injection N46 does not have that sensor and does not suffer these failures.
  7. 7Medium severityCommonFrequency: Common2.0 Ingenium diéselEGR fouling and AdBlue system faultsThe EGR valve gets clogged with soot as on any modern diesel, and the Ingenium diesel's AdBlue system fails fairly often according to several sources, with warnings that can end up preventing the engine from starting if they are not dealt with.
  8. 8Medium severityCommonFrequency: CommonOM654NOx sensor failure and SCR/AdBlue system warningsIt is the fault OM654 owners cite most across several models: the NOx sensor or the AdBlue injector/doser in the exhaust aftertreatment system (SCR) fails, and an emissions-related warning light comes on. It does not usually immobilise the car straight away, but it should be checked soon.Repair (garage): €700–€850Appears at around 85,000 km
  9. 9Medium severityCommonFrequency: Common3.0 TDI V6Control unit software with a prohibited emissions strategy (NOx and AdBlue)Germany's KBA ordered a software update for the Euro 5 and 6 3.0 TDI V6 engines from Audi, VW and Porsche: a warm-up strategy that reduced NOx only on the test bench and, on the 200 kW A6 and A7, limited AdBlue dosing. The update is free.Repair: €0
  10. 10Medium severityOccasionalFrequency: Occasional1.5 dCiNOx trap and AdBlue system on the Euro 6 1.5 dCiThe 2015 Euro 6b 1.5 dCi engines had a badly calibrated NOx trap that Renault corrected with recall campaigns. On the Blue dCi (from 2018), the AdBlue pump, tank or injector can fail, with an emissions warning and even the car locked out with a full tank.
  11. 11Medium severityOccasionalFrequency: OccasionalBMW B57AdBlue/SCR system fault (NOx sensors, heater and pump)A specialist garage considers the B57's AdBlue/SCR system the fault that most often leaves cars immobilised: a NOx sensor, the quality sensor, the heater or the pump usually fails, and topping up the tank rarely stops the countdown of remaining starts.
  12. 12Medium severityOccasionalFrequency: Occasional2.3 MultiJetAdBlue (SCR) system faults and a saturated particulate filter on the Euro 6On the 2.3 Euro 6d with AdBlue, a German garage cites warnings caused by crystallised urea, aged fluid or the NOx sensor that end in limp mode or a no-start lockout; a commercial website adds that the particulate filter becomes saturated with short journeys. These are qualitative sources.
  13. 13Medium severityOccasionalFrequency: OccasionalOM656NOx sensor failure and AdBlue (SCR) system warningsTwo OM656-specific guides place the SCR/AdBlue system among the engine's sensitive points (one of them cites the NOx sensors and the AdBlue injector), especially with short journeys and poor-quality fuel. There are no public failure figures: we rate it occasional, not a series defect.
  14. 14Medium severityOccasionalFrequency: Occasional1.6 CDTIAdBlue (SCR) system failure on Euro 6 versionsOn Euro 6 versions with AdBlue, the SCR system can fail through crystallisation of the fluid or the use of a non-approved additive, with repairs that usually exceed €1,000 and can approach €2,000; one Mokka X 1.6 CDTI owner describes it as the worst problem with the car.Repair (garage): €1,000–€2,000
  15. 15Low severityCommonFrequency: CommonM270/M274NOx sensor failure (code P2200) on the M274Yes: the M274 can throw fault code P2200 because of a NOx sensor failure, a component of the emissions control system. A German specialist workshop describes it as a frequent fault, with a repair cost of between €100 and €500.Repair (garage): €100–€500
  16. 16Medium severityRareFrequency: Rare1.5 / 2.0 EcoBlueEmissions system warnings (AdBlue/EGR) and injector wearOn the Ford Focus IV and Kuga III, generations that now only use EcoBlue, some owners report, occasionally (not in the majority), AdBlue system warnings or injector failures. It is a small sample, and we have not found that Ford has announced a campaign of its own for the EcoBlue for this reason.
  17. 17Low severityOccasionalFrequency: Occasional2.2 MultiJet / BlueHDi (Stellantis)AdBlue (SCR) system: the warning light may not come on if the urea doser failsStellantis is correcting with software a fault whereby the warning light may not come on if the AdBlue urea injector stops working (Boxer, Jumper and Movano 2020-2022) or if the SCR diagnostics fail. The declared risk is to emissions, not safety.
  18. 18Low severityRareFrequency: Rare2.3 dCi (M9T)SCR system and AdBlue tank faultsOn Euro 6 engines with AdBlue there are documented SCR system faults. On the Navara D23 2.3 dCi EU6b (2016-2019) a software update campaign was carried out, covering 1,012 units in Poland.

Engines with faults with AdBlue

Problems with AdBlue by make

Problems with AdBlue in your car

25 cars have several documented faults with AdBlue. Choose yours to see only the ones that affect them, by engine and by year.

Citroën 6
DS 1
Mercedes-Benz 6
Opel 2
Peugeot 9
Toyota 1

How much it costs to repair a fault with AdBlue

Sorted from the most expensive repair to the cheapest. Prices in Spain including VAT (parts and labour); what each figure includes is on its page.

How we calculate costs · The most expensive repairs across all engines

OBD fault codes with AdBlue

The codes the ECU usually stores when this part fails: what they mean, causes and what to check.

Frequently asked questions

Is it legal to delete AdBlue?

No: removing any emissions reduction system is prohibited, and the ITV (the periodic technical inspection in Spain) can detect that the AdBlue system has been tampered with through the OBD test, so the car would fail the inspection. Tampering also voids the manufacturer's warranty, and on commercial transport vehicles the fine can reach €20,000.[18]

Which engines have the most faults with AdBlue?

By severity and frequency, the 1.5 BlueHDi (AdBlue tank and pump failure, medium severity), the 1.6 HDi (AdBlue tank and pump fault (1.6 BlueHDi), medium severity), the 2.0 HDi (AdBlue tank crystallisation and failures (BlueHDi), medium severity), the OM642 (emissions defeat device (AdBlue/EGR) and software update campaign, medium severity), the 2.0 BlueHDi (AdBlue (SCR) tank and pump failure, medium severity) and the BMW N43/N46 (injector, ignition coil and NOx sensor failures (N43), medium severity). In total we have documented 18 engines with faults with AdBlue.

How much does it cost to repair a fault with AdBlue?

It depends a lot on the engine or car. At an independent garage, from €100 to €2,000; at a dealer, from €0 to €1,500, including VAT, based on the 8 faults with a documented cost. The most expensive is AdBlue (SCR) system failure on Euro 6 versions (1.6 CDTI).

What symptoms does a fault with AdBlue cause?

The most frequently cited in the documented faults: adblue system warning, engine fault warning light (check engine), gradual loss of power, "pollution control system faulty" message, hard starting or engine will not start and increase in fuel consumption.

Sources

Every fact on this page links to its source. If you find an error, let us know.

  1. 1.Mercedes M274: Typische Probleme & HaltbarkeitGebrauchtwagenberater · Motoring press · consulted 27 September 2026 · in German
  2. 2.El aditivo de AdBlue que debes usar para evitar una reparación de 2.000 euros en tu coche diéselAutopista.es · Motoring press · published 1 April 2026 · consulted 27 September 2026 · in Spanish
  3. 3.Twin dosing en diésel: el fallo que dispara una avería de más de 1.000 euros en el tallerMotor16 · Motoring press · published 22 September 2026 · consulted 27 September 2026 · in Spanish
  4. 4.OCU y BEUC consiguen que Stellantis amplíe la garantía de los depósitos AdBlue defectuososOCU · Consumer association · published 27 December 2024 · consulted 26 September 2026 · in Spanish
  5. 5.La OCU quiere tomar medidas ante los problemas del sistema de AdBlue de Citroën y Peugeotcoches.com · Motoring press · published 30 May 2023 · consulted 26 September 2026 · in Spanish
  6. 6.Solución fallo AdBlue Peugeot, Citroën y Opel: evita cambiar el depósitoST Automoción · Other source · published 11 December 2025 · consulted 26 September 2026 · in Spanish
  7. 7.Stellantis amplía las compensaciones por los problemas técnicos de sus depósitos AdBlueMinisterio de Derechos Sociales, Consumo y Agenda 2030 · Official body · consulted 26 September 2026 · in Spanish
  8. 8.AdBlue : problèmes en pagailleFiches-Auto · Motoring press · consulted 27 September 2026 · in French
  9. 9.OCU y BEUC consiguen que Stellantis amplíe la garantía de los coches con AdBlueOCU · Consumer association · published 27 December 2024 · consulted 26 September 2026 · in Spanish
  10. 10.Stellantis ataca el problema del AdBlue con una medida especial para los afectados de Peugeot y CitroënMotor.es · Motoring press · published 13 December 2024 · consulted 26 September 2026 · in Spanish
  11. 11.Compensaciones para los usuarios de vehículos Citroën, DS, Opel y Peugeot afectados por un fallo de fabricación de los depósitos AdBlueConsumo Responde (Junta de Andalucía) · Official body · published April 2025 · consulted 26 September 2026 · in Spanish
  12. 12.Más problemas para Stellantis: ahora tendrá que indemnizar también a los afectados por el AdBlueAutopista · Motoring press · published 30 December 2024 · consulted 27 September 2026 · in Spanish
  13. 13.El fallo que afecta a cientos de coches y que ahora la OCU denuncia para reclamar indemnizacionesAutopista · Motoring press · published 29 May 2023 · consulted 27 September 2026 · in Spanish
  14. 14.Fiabilité Mercedes Classe E (2016-2023)Fiches-auto.fr · Motoring press · consulted 27 September 2026 · in French
  15. 15.Fiabilité Mercedes GLC (2015-2022)Fiches-auto.fr · Motoring press · consulted 27 September 2026 · in French
  16. 16.Audi inicia la revisión de 151.000 vehículos diéselMerca2 · General press · published 14 November 2018 · consulted 9 October 2026 · in Spanish
  17. 17.Audi llama a revisión a 850.000 coches ante el escándalo de las emisionesEl Independiente · General press · published 21 July 2017 · consulted 9 October 2026 · in Spanish
  18. 18.Anular Adblue de tu cocheMotor Mapfre · Motoring press · published 20 August 2024 · consulted 2 October 2026 · in Spanish