The autonomy of your Q3 estimated by the manufacturer is 8000 miles. Some users say that the effective autonomy is around 3000 or 4 000 miles.
The volume of the tank on your Q3 is 12L.
When less than 1500 miles of mileage are remaining, a warning light appears on your dashboard. An audio signal sounds to warn you to fill up. Below 650 miles, an AdBlue® warning is illuminates along with a message informing that restarting the car is impossible once the tank is empty. When the tank is empty, a message is displayed along with three audio signals. When the tank is completely empty, pour at least 5,7L AdBlue® in the tank to turn the AdBlue® warning off. Leave the key in the ignition 2 minutes without turning the engine on.
When your tank level reaches 0 miles, you will not be able to restart the engine after it has stopped. You will need to fill the tank with AdBlue®. If your engine is still running, you can drive you to an AdBlue® filling station. Fill the tank with 5.7L, which will switch the warning lights off. If the car does not restart immediately, wait for two minutes for the system to detect the AdBlue® in the tank. If the AdBlue® tank is empty, and the message “autonomy= 0 miles” is displayed on the dashboard, turn the key in the ignition for about 15 seconds and then start the engine.
This information can vary on some vehicles of the same model in relation to the options chosen by the manufacturer.