What should I do if I shut off my diesel during a DPF regeneration?

Start with the exact dashboard message and your truck's owner manual. An interruption by itself does not establish that the filter is damaged or needs replacement. If the truck runs normally and the manual calls for driving to complete cleaning, follow that vehicle's instructions when it is safe to do so. There is no single speed, duration, or parked-regeneration procedure that applies to every diesel pickup. Equipment and controls vary by year. Do not leave a truck running in a garage to finish a cycle. Keep a hot exhaust away from dry grass and other combustible material, including after shutdown. Do not improvise a parked regeneration by holding the accelerator down. The bigger concern is a repeated pattern: cleaning requests that never clear, a check-engine light, reduced power, or a service message. Record the wording and arrange diagnosis. A service warning is not an invitation to keep driving harder. Follow any stop-driving instruction immediately. If this happens often because every trip is short, discuss your operating pattern with a shop familiar with the engine. The useful question is why cleaning cannot finish, or why a warning keeps returning. Simply clearing a code or buying a filter without a diagnosis can leave the original problem untouched.