DPF issues and limp mode, w203 cdi

[c-class]

Hello everybody,
My w203 2005 200 cdi has been having some issues lately. It throws the check engine light and when scanned with the icarsoft device it shows the 3 codes attached as pictures. The issue is intermittent and mostly comes when the tank is over half full which leads me to believe the car is trying to clean it's dpf. If the codes are cleared the car drives normally and has full boost for the next hours. When the issue comes back the car goes into limp mode sometimes without throwing the EML, and sometimes the EML comes on but the car doesn't go in limp mode, this makes me think that I'm dealing with 2 different problems here. Can anybody point me in the right direction? The car has already got the DPF sensor replaced but no luck.
Any help is appreciated

 

[onefortheroad]

Were the dpf sensor hoses checked for blockage ?

Also get some live data readings for the dpf sensor.

 

[alexanderfoti]

Yes as above! The rubber hoses to/fromt the DPF differential pressure sensor are likely full of soot. You may as well replace the hoses and the sensor whilst its off as its a common failure and cheapish.

 

[c-class]

Thanks for your responses, finally found the time today to look into the problem. Undid the hoses and made sure they weren't blocked, and also made sure the connecting points where the hoses mount on the exhaust weren't blocked and cleaned them but after driving for a bit the fault code came back. Also checked the live data while driving and with the revs below 2k it showed zero or -1. Above 2k it went up to 3 or 4. The values were checked with the icarsoft v2.0 and the unit is hPa in case somebody is interested. Any clues to what I should check next? I also tried gently blowing into the sensor while plugged in and the values were moving, which leads me to believe the sensor is fine.

Edit
Maybe it's worth mentioning, when the car is idling it stink a bit like an old diesel and I always thought it is because of the second cat being a bit rusted and maybe it has a hole in it. Could it be that there just isn't enough back pressure for the sensor to read?

 

[onefortheroad]

At tick over it reads something like -0.4 to + 0.4 . Anything higher means clogged pipes or dpf blocked.

 

[c-class]

The values it showed at idle were eother 0 and -1. I don't know if the scanner can read values between 0 and 1 but I've only seen whole numbers. The higher numbers were only when revving the car up to 3.5k. I don't think the dpf is blocked since it shows it only is at 60%.

 

[onefortheroad]

There's a section within the dpf about doing a forced regen. Follow the instructions, the icarsoft unit will guide you through a series of questions firstly, it will at some point reteach the valves of a newly fitted dpf sensor, the regen will fail , but the dpf sensor should now be calibrated. Be sure to repeatedly delete error codes otherwise it won't work.

 

[c-class]

I was planning on doing that, should I do a forced regen while driving or while standing? I saw that there are two options under the dpf section. The regen while standing seems to work since I only tried it once to see if it did anything and the revs went up and so did the temps, but since I didn't have the time and it wasn't the best place I stopped it.

 

[c-class]

I tried doing a forced regen today, but it failed since it showes that not all the needed conditions are fulfilled, specifically catalytic converter temperature isn't withing specific range. The car had been driven and was up to temp. Could it be that the cat was just too hot? Another interesting thing I noticed is that the ash content is at 0% load state of the filter is at 105% which leads me to belive that the car maybe has had the dpf removed from the previous owner. This could also be the reason why the sensor reads 0 as pressure difference since the 2 hoses connect before and after the dpf. Can anybody shed some light on this?