The Passat, Q7 and Touareg use AdBlue.

See here; http://www.myturbodi...dpf-audi-q7.htm for how it's used in DPF function.

Yes, but it's not used in the DPF, the adblue injector is after the DPF and serves to further reduce NOx emissions.

Sorry I stand corrected. I wasnt sure what it was that went in the tank. I just assumed that it was wee that went in the tank. I just can't belive that the fluid ford use is £50 a litre tho!!

Yes its the same stuff Peugeot/Citroen use as Ford developed the engine jointly with them.