I have in the past read various references you have made to "particulate filters" in diesel cars. I purchased a Volvo D3 S60 diesel manual in December. Within six months the warning light came on indicating that the particulate filter was clogged. I took the car to Volvo who cleaned it and suggested that most of my journeys were of a short duration I should, from time to time, drive aggressively in 4th gear to burn off the particulates accumulating in the engine. I have done this and despite a couple of journeys of over an hour the warning light has again come on, just a few months later. I can believe this is normal and have taken the car back to Volvo for investigation. I would appreciate your comments as to whether this is normal and my fault or whether you think there is an inherent fault somewhere in the car.