AdBlue system repair cost (2025 UK Prices)

On many diesel cars made after 2015, manufacturers fitted AdBlue systems to reduce harmful exhaust emissions. Whilst they are very effective at reducing pollution, on aging cars or those that are not looked after well, these systems can sometimes cause issues.

In this article, we’ll take a look at how much repairing an AdBlue system typically costs, from basic diagnostics to full replacement parts.

How much does it cost to repair an AdBlue system?

Prices to repair AdBlue systems range from around £75 for a diagnostic test or software update, to over £2,000 if you need to replace the catalytic converter, pump or other complex parts of the system.

In some cases, a software update, forced regen or code clear can solve an AdBlue fault. Independent garages typically charge £75-150 for this, whereas a dealer may charge more.

If you need to replace the AdBlue pump or catalytic converter, expect to pay upwards of £1,000 for parts and labour.

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What does AdBlue do?

AdBlue is used as part of the SCR (Selective Catalyst Reduction) system in certain diesel cars. This system works in addition to the regular diesel particulate filters to further reduce harmful emissions.

The AdBlue is injected into the SCR catalytic converter, and sparks a chemical reaction that breaks down harmful nitrogen oxides into water and harmless nitrogen gas.

Why does my car need AdBlue?

In order for the SCR process to function, a chemical reaction must occur. AdBlue fluid contributes ammonia to this chemical reaction in the form of synthesised urea. This reaction transforms nitrogen oxides into water and nitrogen.

Without the AdBlue fluid, the SCR system cannot function correctly.

What happens if I don’t fill up with AdBlue?

A malfunctioning SCR system, due to either a lack of AdBlue or a fault, will no longer convert the harmful emissions; your car’s ECU will detect this and give various warnings and alerts.

If you completely run out, many modern cars will enter limp mode to help reduce the volume of emissions, and even refuse to start once the engine has been turned off.

Alongside this, running your car without sufficient AdBlue can cause problems with the injector, pump or SCR catalyst - all things that are expensive to repair.

How much AdBlue should my car use?

AdBlue consumption depends on the car you have and the type of driving you do. Some manufacturers suggest 3-5% of your diesel consumption, which roughly translates to 1.5 - 3L of AdBlue per 1,000 miles.

If your car is using much more or less than this amount, that may be an indicator that something is wrong. Most garages, especially independent specialists and dealerships, will be able to scan the car for fault codes in this instance.

Can I drive with an AdBlue system fault?

No, you should not drive your car with an AdBlue fault.

In fact, many modern cars prevent you from starting the engine if there is a serious AdBlue fault. In others, the car will go into “limp mode” which is a reduced performance mode. It is not safe to drive in limp mode.

Repair your AdBlue system with Bumper

If you’re worried about expensive repairs, anything from AdBlue issues to bodywork, Bumper can help spread out the cost with easy car repair finance. Apply online and choose from 1000s of approved garages.

Author - Joseph Law

Joseph has been writing about cars for over eight years and writing for Bumper for over three, blending his passion for automobiles with a talent for storytelling.

Joseph has written about engineering and cars for Autozilla, Komaspec, and several engineering manufacturers. When he's not writing or tinkering with one of his cars, Joseph dreams of owning an Alfa Romeo 33 Stradale.