Not usually. I enabled the DPF percentage gauge with FORSCAN so I would know, otherwise the only way to tell is I think it disables auto start-stop while it's doing it. The owner's manual says there are times it will tell you but I think that's only if it isn't able to do the passive regen enough i.e. really short trips all the time. My 20 minute drive to work is enough that I've never seen that message.