Touareg: 2008 R5 TDI
Join Date: Dec 2016
Second Vehicle: Still looking
Thanked 35 Times in 33 Posts
Obviously a lot of people are driving Touaregs and other VW cars in city traffic, and generally none of them have problems with DPF regeneration. This particular car most likely had something other wrong with it, and that was what possibly caused the DPF problem - if it was a DPF problem in the first place.
As for the DPF cleaning: the general consensus about this is, that most non-invasive DPF cleaning methods (that somehow flush the filter with some fluid) do not really work, and even though they might remove some of the ash, they will definitely not regenerate to the filter to anywhere new level. They might help get rid of the DPF warning for a while, but in the long term they're not only not a solution, but cost more than buying a new filter in the first place.
There's also another method of DPF "cleaning", where they open up the filter housing, and actually replace the filter elements in it, then wield back the housing. This method theoretically resets the DPF capacity to original, but also has its own problems. The most prominent ones are that the new filter elements might not fit the housing perfectly, and thus the exhaust can blow by the filter, defeating its purpose. The other problem is that the DPF gets extremely hot, and the new welds might not be able to withstand this temperature. This will obviously result in a very dangerous situation, where the car can burn down during a regeneration attempt.
All in all, the only real and reliable solution to "clean" the DPF is to replace it with a completely new one. Now, obviously VW will charge a small fortune for a new filter, but there are reputable 3rd parties that supply perfectly fine and reliable new filters, which can be purchased at reasonable prices. In the end DPF is just another "wear" item in a car, that has to be renewed every once in a while - even though with most cars that's just once (or two at most) in the lifetime of the vehicle.
However, your complaint on there being no indication of the DPF generation being in progress is valid, and it would be useful in many ways - even if that's not helping to avoid interruption of the process, because as said, in the end that doesn't matter much, and generally does not cause any problems whatsoever, unless there's something else wrong with the car. But if there would be such an indication, and the driver could see it start happening more often then usual, it could possibly help catch a lot of other problems early, like injector, air intake or boost problems, which all increase the amount of soot generated and thus also the frequency of DPF regenerations.
It is beyond me why VW decided not to provide _any_ feedback on DPF regeneration visible to the driver - but I'm pretty sure they had a very good business reason to do so. Like saving 50 cents in manufacturing costs of a car with a sticker price of $70.000+.