AdBlue (SCR)
A urea solution that after-treats nitrogen oxides on modern diesels; it runs out and must be topped up periodically.
AdBlue is the brand name for an aqueous urea solution (AUS 32) that is injected into the exhaust system of modern diesel cars with an SCR catalyst. There it converts nitrogen oxides into nitrogen and water, needed to meet the Euro emission standards. It is in a separate tank, apart from the fuel.
Consumption is roughly around 1 to 2 litres per 1,000 km, strongly dependent on driving style and load. The tank must be topped up periodically, often between service intervals; the car warns well in advance. If AdBlue runs out completely, many diesels limit the power or do not restart, because driving without working after-treatment is legally not permitted.
On spec sheets we mention AdBlue only as a factual characteristic of diesels with SCR; consumption figures are indicative and use-dependent and not a value measured by us.
See also: Particulate filter (DPF/OPF), APK (periodic vehicle inspection), Timing belt or chain
Source: Concept explanation; consumption use-dependent, indicative
No tax or financial advice. Every figure shows its source and reference date. Always compare with an independent adviser and the official source.