AdBlue Faults Explained

AdBlue warnings can be alarming, especially when they come with a countdown to no-start. Here's what the system does and what to do when it plays up.

What AdBlue does

AdBlue is a urea fluid injected into the exhaust (the SCR system) to convert harmful NOx into harmless nitrogen and water. It's fitted to most modern diesels. When the system detects a fault, the law requires it to warn you and, eventually, prevent the car from restarting.

Common causes

• Faulty NOx sensors
• AdBlue injector or pump problems
• Crystallised AdBlue blocking the system
• Quality or level sensor faults

How we fix it

We diagnose the actual fault first, often a sensor or injector that can be repaired or replaced. Where appropriate (for off-road, motorsport or export use), an AdBlue solution resolves persistent SCR problems. We'll give you honest advice on the correct route for your car.

Seeing an AdBlue warning? Get in touch and we'll get to the bottom of it.