Our BMW 1 Series is showing a DPF light - is this because we only use it for short journeys?

I recently bought my son a BMW 1 Series for his 18th birthday. Soon after the filter light came on. We took it to a garage to be looked at and the turbo was burnt out, so had to be replaced. We also had the filter cleaned. The light went off and the car had much more power then when we bought it. When we originally took it there was black soot coming up onto the inside of the bonnet, which was thick black on a white car. It also smelt. Three weeks on, the light is back on. The car has done 147,000 miles. Do you think I should just by a new DPF system for this car? I don't want any problems for my son with it. I have told him to call the garage again and let them know what's happened. I've read some posts on here and you recommend taking it up the motorway for a while until the DPF kicks in and regenerates. I don't want my son to have to keep doing this, he only passed his test six months ago. He does small journeys to work and back, could this be the problem? Surely you cannot buy a car that does not allow you to do short journeys. That's crazy.
Never any point in replacing a turbo without also replacing the turbo bearing oil feed and oil return pipes because if they are blocked with carbon the turbo bearing will not get properly lubricated (if at all) and the new turbo will soon fail. I think you are mixing up EGR and DPF. I guess you had the EGR cleaned out or replaced. But at 147,000 miles, it is likely that the DPF will be blocked with ash from the soot it has burned. If the DPF is already 75 per cent full of ash and the car is used for short runs then the DPF will not be able to regenerate the soot from the starts of those short runs. Sometimes a DPF can be chemically cleaned of ash by the Ceramex process. Sometimes the DPF is too far gone and the car needs a new one. First job, though. replace the turbo oil feed and oil return pipes. High mileage diesels are not the 'bargains' they used to seem to be.
Answered by Honest John on

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