The volume of the tank on your X5 is 15L.
Below 1500 miles of mileage, a warning is displayed on the dashboard and a alarm signal sounds to warn you to fill up your tank. Below 650 miles, an AdBlue® warning appears on the dashboard, along with an alarm sound and a message that warns you that restarting your car will be impossible once the tank is empty. If the tank is empty, you will be warned by a message and 3 audible alarms. Once the engine is turned off, it cannot be restarted.
When your tank level reaches 0 miles, you will not be able to restart the engine once it has stopped. You will need to fill the tank with AdBlue®. If your engine is still running, you can still drive to a service station.
This information can vary on some vehicles of the same model in relation to the options chosen by the manufacturer.