Emission control with AdBlue®1

AdBlue is an additive used in SCR2 systems to reduce harmful emissions from diesel engines.

In the SCR system, AdBlue and the exhaust gas component nitrous oxide are converted into nitrogen and water vapour, which considerably reduces harmful nitrous oxide emissions.


AdBlue is a colourless fluid consisting of 32.5% urea3 in deionised water and is manufactured in accordance with the ISO 22241 standard. It has been specially designed for SCR cleaning technology for diesel engines.

There is a separate AdBlue tank in the car, which is topped up via a filler pipe located beneath the cargo area floor. Consumption is dependent on driving style, external temperature and the system's operating temperature.

Conditions for driving with AdBlue

There must always be AdBlue of the correct quality in the tank to allow the car to start. The SCR system is very sensitive to contamination.

The exhaust gas cleaning system constantly monitors the tank level, quality and dosage of AdBlue. A message is shown in the combined instrument panel if anything is wrong.


AdBlue is required for the function of the SCR system and legal emissions compliance. It is illegal to modify or manipulate the AdBlue supply system in any way so that no AdBlue reagent is consumed when it is required for legal exhaust emissions compliance. Any such tampering may be a criminal offence which may lead to legal prosecution actions.

It is not permitted to operate the car with an empty AdBlue tank, since it will no longer be compliant with the legal requirements for exhaust emissions. Therefore, the car is equipped with a warning system to inform when AdBlue refilling is required. When the fill level in the AdBlue tank is getting low, warnings are displayed to inform that AdBlue refilling is required.

  1. 1 Registered trademark belonging to Verband der Automobilindustrie e.V. (VDA).
  2. 2 Selective Catalytic Reduction
  3. 3 CO(NH₂)₂