47,000 miles would be ridiculously early in a DPF’s life cycle to be ash restricted. You’d have to be doing some things egregiously wrong. Or have a major failure of some sort. I suspect (key word) that these trucks can get confused when they regularly are not seeing fully successful regenerations. I have some theories on this but I don’t have the time or the resources to “test”.
These trucks will pause a regen cycle if the truck is put in park or shut off. It'll pick back up when the truck begins to move again. However, quite often, the conditions inside the DPF are different than when it began the cycle. Temps may be lower, drive cycle may be different, etc. So I think you don’t get as effective a “burn out” if the regeneration is interrupted. If this becomes a habit, I think you end up with build ups that the truck sees as “ash” when in reality it’s soot. Build up after build up, just causes more of the same. Ultimately the truck pops P242F thinking there’s too much ash restriction when there really isn’t. Once that sets, active regen won’t work anymore because the truck inhibits it. The trucks that are routinely driven in stop and go, or low speed short cycle operation, seem to be most at risk for this. Since there’s no outward notification to the driver that a cycle is running, they can inadvertently interrupt regen cycles if they aren’t paying attention. (Yes you can see the message if you keep it on the DPF screen, but the average driver doesn’t do that. In fact, most people don’t even look at the page)