Been doing a bit of internet research and apparently this new addition to the ever complicating life of the motor car was originally introduce by Peugeot..
Any interesting thread regarding customer perceptions of the system after use..
Is this additive ( which I beleive is called "Eolys" ) present in the Renaults ?
What is the life of the Renault
Here's a picture of the Peugeot system..
Horatio is right it would appear to be downstream of the