What it means
It commonly warns that diesel exhaust fluid is low, or that the selective catalytic reduction system has a fault. Amber usually means refill or check soon, while a countdown or no-restart warning can indicate that the vehicle may not restart after being switched off; colour and behaviour vary by manufacturer.
What the symbol looks like: A message or icon showing an AdBlue or DEF tank, often with a fluid-level mark; the exact graphic varies by manufacturer.
Why it comes on
- Low AdBlue/DEF level
- Incorrect or contaminated fluid
- Fault in the fluid-level or quality sensor
- SCR system, injector, or pump fault
- SCR-related emissions fault
What to do
- Read the message and owner's manual to identify whether it calls for a refill or service.
- If low fluid is indicated, use only the fluid specification stated in the manual and follow its refill instructions.
- Do not overfill or put AdBlue/DEF in the diesel tank.
- If the warning remains after refilling, or a countdown or no-restart message appears, arrange service promptly.
Can I keep driving?
If the warning is only for low fluid, refill promptly and follow the manual; some vehicles restrict restarting once the countdown expires. If there is an SCR fault or the vehicle is limiting operation, avoid unnecessary driving and get it checked.
Symbols and colours differ between makes and models. Your owner’s manual shows the exact lights of your car.