CEL E320 bluetec
CAT could be clogged but your mechanic should have caught that if they diagnosed the dpf. there is also a collector pipe under the turbo that leaks smoke under hood when cracked(from age/mileage) but I’m not sure since it’s coming out the back too, what color smoke?
this is how my car was when the collector pipe under the turbo had a crack in it. Smell was very acrid and coming in through my vents visibly
out the back is either old soot coming out of exhaust especially if you really only see a plume under acceleration. If it’s at all times injectors over fueling which increases the car Nox, soot etc.
if the cat was blocked I’d assume you’d also have severe limp mode and maybe trouble even starting, it’d be like coughing
I looked through some old forums and they said to look inside the cat with a light
Last edited by BetterDaze; Mar 12, 2024 at 01:46 PM.
you can try resetting the lambda but do NOT alter anything asking for injector values nor quantities. You can also try telling the car there is a new NoX sensors or cat….all adaptation options
The old dpf could have skewed those readings, lastly if you have no drivability issues, full throttle on highway to blow that gunk out and if you feel okay maybe drive long enough for it to regenerate then check and see if your scanner will tell you if it actually did one but start with seeing when it last might’ve
No CEL is a good sign but there could be pending codes too you can check for
Last edited by BetterDaze; Mar 12, 2024 at 06:38 PM.
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There is either an actual blockage somewhere or a sensor is off-reading. start with the dpf differential pressure sensor and work all the way up to the back pressure sensor next to the turbo. Check inside their ports, clean them and try to reset again.
B28 is the back pressure sensor and sits to the right rear of turbo between it and the EGR. That port can fill with soot and make the car think back pressure is too high triggering limp mode under hard acceleration
i bet your car is trying to regen like normal your past 3-4 drives and when it initiates you see smoke coming from that leak. It does kinda sit where it can emit both under the car and flow up through the hood






