Recharge AdBlue Warning lights and what they mean
Red warning lights mean you should stop the car as soon as it's safe.
Yellow warning lights mean that action is required.
Green warning lights are for information only.
The red warning appear when there is no AdBlue range left; once this happens the car will not restart once the ignition is turned off.
This is not a fault, but a required feature of the system. If this stage is reached the system will need a full top-up before the car can be restarted. Further information is available in the vehicle handbook.