Investigate soonamber light
AdBlue Low Level Warning
Your diesel needs AdBlue top-up soon — the car will refuse to start if it runs out.
What it means
An amber icon of a fluid container, sometimes with the words AdBlue or DEF. AdBlue (diesel exhaust fluid) is injected into the exhaust of modern diesel cars to reduce NOx emissions. If the tank runs dry, the car will enter a countdown and eventually refuse to restart until it’s refilled.
What to do
- 1Top up with AdBlue as soon as possible — available at petrol stations, motor factors and supermarkets.
- 2Check your handbook for the correct type, capacity and filler location (often next to the fuel cap or in the boot).
- 3Do not ignore the countdown — once it reaches zero the engine will not restart after switching off.
- 4If you’re unsure how to fill it, most garages will do it for you.
Likely causes
- •AdBlue tank naturally depleted over time
- •AdBlue crystallising in cold weather (still usable once warmed)
- •Faulty level sensor
Rough UK cost
AdBlue: £15–£30 for 10 litres (enough for most cars). Sensor: £80–£200.
Prices are a guide only — always get a written quote before any work.
Heads up: Carautonomy is for general guidance only. If your car is behaving oddly or any red light is on, get it inspected by a qualified mechanic.