Also, the carbon build up has been beaten to death on the 335 N54, the 335d and the X5d. The bottom line is BMW designed a junk system and has had to take steps to fix it. If it affects an emission component, they HAVE TO FIX IT. They do not have a choice. If they give you any flack, tell them you're going to call the EPA and report them for an emission warranty violation. It's a no BS deal. If something is malfunctioning (DPF not regenerating etc) it's a serious issue and they have to fix it. Further, the EPA is forcing mfgs to extend warranty coverage on the DPF systems that are having problems as it causes a huge pollution issue. A buddy is a duramax tech, and they were just forced to replace the entire DPF/EGR system on a 2008 duramax that had 575,000 miles on it. The EPA didn't care, said the system should work for the 'life' of the vehicle and the truck still ran otherwise.

If the carbon builds up to a point it clogs a sensor or the EGR or soemthing like that (and you get a readable fault), the'll have to fix it. They'll try and get you to pay for non-standard maintenance (carbon blasting) but that's for the uninformed consumer. And 'bad gas' is BS, she's an idiot. All diesel is ultra low sulfur in the US anymore and it has to meet certain requirements. There's no such thing as 'bad gas' when it comes to diesel fuel anymore. Water sometimes, yes, but that'll cause different issues.

The EPA doensn't play ball. Ask for the GSM next time she sends you some bonehead email.