OM651 recurring fault codes and limp mode

[edext24]

Hello,

I have a Mercedes C250CDI from 2011 (OM651). About one month ago I had P0299 (low boost), P2279 (air intake leak) and P2463 (soot in DPF).

I performed a smoke test and figured that the issue was from a badly mounted intake manifold. I replaced the seals, re-installed the manifold, did the smoke test again and everything was perfectly sealed, no smoke coming from anywhere. The error codes disappeared for about 3 weeks.

Two days ago, engine light came up on the dash again, with a limp mode, with the same error codes mentioned above. I did the smoke test once again, and there are no leaks, even though I have those errors.

The first time, someone from MB told me that the problem was with the boost leak, and not the DPF, and that the DPF didn't show bad values. It was true then, because there was a massive leak at the intake manifold which got solved.

The soot now is at about 11g.

Cannot figure out what it could be, and I don't want to change 10 different things, spend a bunch of money and still not fix the issue.

Should also mention that a few days after I first fixed it, a fuel return hose cracked and spilled a lot of fuel on the engine until I got home to fix it. Removed the diesel fuel from the engine bay with a syringe and wiped it as best as I could, I'm mentioning this because maybe fuel got onto some sensors or something.

 

[MinionBob]

what a are pressure like before/after DPF?

 

[Dean Fletcher]

My guess would be a Sheared bolt on the inlet manifold. Do you hear a vacuum type sound when you put your foot down coming from dash area?
The boost leak and low boost might be the intake manifold and the soot accumulation will be because the car won’t regen while there is codes showing up and the EML on.

 

[edext24]

My guess would be a Sheared bolt on the inlet manifold. Do you hear a vacuum type sound when you put your foot down coming from dash area?
The boost leak and low boost might be the intake manifold and the soot accumulation will be because the car won’t regen while there is codes showing up and the EML on.

The intake manifold is sealed. No air leaks there.

 

[edext24]

I also did a DPF cleaning, which got rid of the issue for about 100km, and then it came back. Didn’t have the chance to read the codes yet. Will post an update

 

[Dean Fletcher]

I also did a DPF cleaning, which got rid of the issue for about 100km, and then it came back. Didn’t have the chance to read the codes yet. Will post an update

I had a E250 for about 7 years. I had all the common issues
Intake manifold
Fuel filter housing
2 water pumps
But also had this niggle going into limp mode every few months, garage couldn’t diagnose its kept changing the pressure sensor.
I bought a can of DPF cleaning took pressure sensor off and fired the whole can equally down the upstream and downstream pipes, left it for 15 minutes then took the car out and hammered it. After doing that it became a yearly thing and the limp mode never came back.
As far as I’m aware the sensor uses the pressure values to determine the fill level and on my car keeps doing unnecessary regens. Only after doing that the fill level went down to 2% and took ages to get back up to 100% and soon as it hit 100% I could see the exhaust temp shoot up and bring the fill level down. Amazing to watch while my Mrs drove on the diagnostic tool.