The passive regeneration occurs with no action taken by the car's computer. It occurs with higher sustained engine loads like freeway driving or fast acceleration onto the highway when exhaust gasses are hotter. These types of loads will produce exhaust gas temperatures (EGT) of about 350-500ºC which thoroughly heat up and burn the DPF. If the car has only short stop-go trips, the exhaust doesn't have a chance to have a good passive burn off and will have more active regens or clog.
The active regeneration "self clean" occurs when filter soot loading is beyond 45% or every 466-621 miles (750-1000 kilometers), whichever is sooner. EGR is shut off and the fuel injectors squirt a little fuel into the engine cylinders after combustion (post combustion injection) that travels to the oxidation catalytic converter and oxidizes to raise EGT to around 600-650ºC. The gasses travel to the DPF and burn up the trapped particulates.
During an active regen the car's computer also temporarily increases turbo boost about 2-4 psi to make up for any lost power. Engine rpm also goes up around 200 rpm on the 2.0L engine. A cycle lasts about 10 minutes and if you shut the engine off in the middle of an active regen cycle, you'll hear the radiator fans in the front of the car running fast (even after the car is shut off) and you may smell a burning rubber type odor. It will resume once you exceed
38 mph after the next engine start (and the exhaust is warm enough).
If the car still can't do an active regen and soot loading reaches 50-55%, it will try to force a 15 minute regen cycle. If you interrupt it by shutting the engine off, the active regen cycle won't finish. There is normally no light or indicator to show when the car is doing an active DPF cycle. If the cycle was interrupted by engine shut off, it'll try again before lighting the DPF warning light on the dashboard
(3 times IIRC). If that happens, drive at about 40 mph for at least 10 minutes in 4th or 5th gear at 2000RPM or higher (Disclaimer: faster would be fine as long as you don't exceed the speed limit).
At 75% loading, the glow plug light will also come on. If you see the warning, go to have the car
service or go to the
dealer so they can explain the warning lights to you. It's still possible to do a
service regeneration, a manually started active DPF regen.
In the 2.0L engine, the automatic active regen is blocked by the car's computer once DPF loading reaches 40 grams. The
service regen must be manually initiated using the procedure below. I'm not sure if the
service regen is the same as the emergency 95% regen so try both methods below.
If clogging reaches 95% (45 grams) it must be manually removed and cleaned since all that combustion could damage or melt the filter due to extreme heat and pose a fire risk. There's a chance the repair would not be covered by the car warranty (maybe the federal emissions warranty) if you ignored the warning light or if the clogging is caused by your driving style.
