13638 posts · Joined 2006. #2 · Feb 5, 2011. The truck will sense a full DPF filter, and initiate a self clean cycle. You have to drive it to clean it. IF by chance it gets full, by you not letting it complete the cleaing cycle, you will have to take it in for service. Audentes Fortuna Juvat.. 398 255 27 108 496 86 135 339