Hi its a universal thing with diesels they all do it especially when treated to lots of short journeys at low speeds, best thing to do is fill it with decent quality fuel and give it a run down the motorway for about twenty miles that will clean most of the crud out, then buy a fuel additive suggest Hydra Maximus I use it in my cab which does a lot of short journeys but because the additive makes the fuel burn more efficiently the regenerations are less aggressive and not as frequent, also stay away from supermarket fuel IT WILL KILL YOUR ENGINE, do not keep stopping when the fans come on as this is known as a aborted regeneration which over time will cause engine/emission system failure.
Steve.
Steve.