I see no reason why the 4.2's DPFs shouldn't be cleaned like those on the 2.0.
Here is a german thread on the cleaning of the 2.0 with important tips as how to force start regen, then pressure clean them DIY.
http://www.a4-freunde.com/showwiki.p...spuelen&page=2
VERY IMPORTANT:
Before removing, start a forced regen via VCDS, then immediately stop and remove. There can't be any oily residues in the DPF, as this prevents pressure cleaning and will destroy it.
Every opening for difference-pressure-sensors, Lambda-sensor and Temp-Sensor have to be closed with screw or appropriate measures.
Clean with a rotary nozzle AGAINST the flow of exhaust gases.
Use pressurized air to dry. Then some hours on a radiator.
Use some non-stick medium for the screws when reattaching.
There is some info, as how to set the Ash-amount in VCDS, but I haven't found the according blocks in VCDS myself yet for the 4.2.
If needed, I can translate more tomorrow, as I am off for
another Audi-meet.
