Servicing · 4 min read
What is AdBlue and why does my car need it?
AdBlue is a urea solution injected into the exhaust of many diesels built from around 2015 onwards. It converts nitrogen oxides into nitrogen and water so the car meets emissions limits.
Running low is not optional
The car will warn you well in advance, then count down. Run the tank empty and the vehicle will refuse to restart once switched off — that behaviour is designed in, not a fault.
Topping up correctly
Use fluid meeting the ISO 22241 standard, keep it clean, and don't decant it into anything that has held diesel or water. Contaminated AdBlue damages the injector and sensors.
The faults we actually see
Crystallised deposits around the injector, failed NOx sensors and heater faults in cold weather are the common ones. They usually announce themselves as an emissions warning with a restart countdown.
Diagnose before replacing
AdBlue system parts are expensive, so we read the live data and confirm which component is at fault rather than replacing sensors speculatively.
Bookings
Book your car into the workshop
Tell us your registration and what the car is doing. We'll come back to you to confirm a date.