The engine wouldn’t cut out the same as it would if you ran out of fuel, however the AdBlue is integral to diesel vehicles. This means your vehicle treats it like fuel and won’t run properly without it.

If you ignore the warning light and the AdBlue runs out the vehicle’s performance will be adversely affected (the vehicle does this to prevent any potential damage to the system occurring). Once you turn the engine off it will not restart if the AdBlue has run out.

Most vehicles will display a warning light on the dashboard when the AdBlue is running low.