Do it yourself
Frequently asked questions about cars and motorcycles
Car tutorial (Do it yourself) Motorcycle tutorial (Do it yourself) Frequently Asked Questions

Theoretical Operation of the AdBlue System on Peugeot/Citroen

Model: Citroen Citroen Various
Part: AdBlue warning light

In this video, we see an animation explaining the theoretical operation of the PSA pollution control system with AdBlue: we observe the position of the catalyst relative to the engine, and the AdBlue tank on the opposite side of the vehicle. In the centre is the catalyst with the DPF: a diesel engine emits carbon monoxide, unburnt hydrocarbons, nitrogen oxides, and particulates, which are eliminated in three steps using the AdBlue treatment. The first step is that all these gases pass through the catalyst; the second step is where the SCR valve converts nitrogen oxides into water and nitrogen with the introduction of AdBlue. Finally, in the third step, there is a 99.9% reduction in particulates. All very nice in theory, but unfortunately, we know the difficulties this system has caused users.

Updated on 9 September 2026 by ScegliAuto

Video tutorial

Related tutorials

How does the Start & Stop system work on PSA Peugeot and Citroen engines?
How does the Start & Stop system work on PSA Peugeot and Citroen engines?
Citroen Citroen Various In this video, we see how the Start & Stop system works on Citroen and Peugeot vehicles. In the city, it often happens that the car has to stop, cont…
AdBlue malfunction on Citroen and Peugeot vehicles
AdBlue malfunction on Citroen and Peugeot vehicles
Citroen Citroen Various In this video, we can see how a Spanish trade association has decided to resort to a Class Action (which is a legal procedure that allows a group of …
How to deactivate the start and stop system on the Citroen Relay
How to deactivate the start and stop system on the Citroen Relay
Citroen Citroen Various Disabling the Start&Stop system on a 2021 Citroen Relay diesel vehicle is a very simple and quick operation that can be done with just one step. To d…

Other guides you may be interested in

How to Reset the Central Locking of the Volkswagen Golf 4?

If the central locking system of the Volkswagen Golf 4 is not working, it is likely necessary to reset the system: to do this, open the driver's door and detach the side panel of the dashboard next to the steering wheel. Under this panel, you will find the fuses, including the one for the central locking, which is indicated in the manual as number 14. To reset the system, remove this fuse from its housing, then reinsert it or replace it with a new one of the same amperage: this will reset the central locking system.

Watch the video!


by ScegliAuto

More videos