Many mechanics advise having your DPF cleaned every 6-9 months to keep it operating at optimal levels, though you may need to clean it more or less frequently depending on your driving habits. If your DPF is in danger of malfunctioning or wearing out, you should see a light on your dashboard, so for most people there’s no need to worry. Active regeneration is when raw fuel is injected into a diesel oxidation catalyst to reach the appropriate DPF regeneration temperatures. Passive regeneration and dynamic generation do not require input from the vehicle operator. Passive regeneration does not require checking engine light codes shown on the vehicle dashboards. 3. Passive I love having the gauge in the instrument cluster that show the level of the DPF, as well as when it is actively in regen mode. I watched the first couple regen cycles and it happened to kick off when I expected, the filter was about half capacity, and I had hit the highway and held speed for about 15 minutes when it started regen. 20 or so So, however long it takes to get to 150 (that's assuming the DPF is at 2.66 or higher soot GPL to force it to begin) and then it runs for 10-15 minutes (haven't timed a full process yet). Seems more like 15 minutes for the regen process plus another 5 minutes of the DPF being so hot that it continues to burn off soot. Let the truck run until it is idling. Wait until the coolant temperature is at least 185 degrees. The coolant temperature gauge is on the left bottom side of the dashboard. Once the coolant has reached 185 degrees, press the regen button and hold it down for ten seconds. The regen switch is a black switch located on the right side of the cab. You can tell that the DPF filter is clogged by observing any frequent forced regens, as well as long ones that seem rather unusual. Typically, a forced regen lasts for less than 40 minutes. So, if your regen lasts more than that, this may mean that your DPF is clogged. Another thing to take note of is a blockage in the DOC. 14690 posts · Joined 2014. #2 · Jun 9, 2016. #1, idle as little as possible, but for one hour occasionally, shouldn't be a big issue. It may run like it's loaded up for a few minutes after you get moving again. #2, what you experienced was "active regeneration", that is when you will notice the drop in economy and the diesel exhaust smell It does not matter if the vehicle speed is sometimes less than 40 km/h. The DPF system will continue the regeneration when the speed increases above 40 km/h again. It does not matter if the vehicle is stopped with the DPF warning lamp ON. The vehicle operator must set the park brake and enable the parked regeneration to begin. Engine rpm increases and raw fuel is injected into the exhaust gas at the exit of the engine to generate the appropriate regeneration temperatures. The stationary vehicle manual regeneration processes take about 30 minutes. It got to about 1/2 and check engine light came on and went into regen. Immediately after gauge showed zero and engine light went out, but within a few miles it’s starting to creep up. I think I have a problem. I think it would be better if the light was still on when I take it to the p.o.s dealer. xm38f.