DPF problem E350 3.0CDI 2009 C207

[vagon]

Hi all

I'm new here, having a small issue with my MB E350 3.0CDI 2009 C207 Coupe. Hope someone can point me in a right direction ?

Bought this E350 a few weeks ago, on the way back from the trader engine light came up. Did not want to bring it back to the seller as was 4hours away and we really wanted the car.

So far I've done :
Full service (oil + all filters)
Brake Discs/pads all around + tyres
Thermostat replacement (someone fitted incorrect one and car did not warm up beyond 75degrees). Now car warms up to 93degrees as it should.

As a result of the wrong thermostat fitted car would not perform DPF regeneration, thus DPF was nearly full and in a need of immediate regeneration.

Regeneration went through (saw the DPF temperatures over 600degrees on my Autel MK808 + ASH & SOOT values went from 9 to zero)

Car drives well, only goes into a limp mode after a few days of daily driving.

In the engine bay I noticed that on DPF pressure sensor B28/8 (original MB one 0281006025/A0071536128) there were undone hose clamps, someone probably investigated the DPF issue not realising there was a problem with the Thermostat as well.

To the main problem :

I still keep getting an error (Error pops up on the scanner after the car is restarted, orange light comes up after 3-4 starts of the car + limp mode):
Error via Autel : 129700 - Stored - The Diesel Particulate Filter Is Defective
Error via obd ELM327 + Torque Pro : P2002 Powertrain - Particlate Trap Efficiency Below Threshold - Bank 1

My suspicion is faulty DPF pressure sensor B28/8, probably got damaged due to blocked DPF for quite some time... On Autel the B28/8 is showing values from -5 to +15 hPa, not sure what healthy car should show but negative values don't seem right ?

DPF is showing clean and working, exhaust pressure seems slightly high for idle..

Any suggestion how to test the B28/8 sensor, or point me to what I should check next would be muchly appreciated.

P.S. Error pops up after the car is restarted. When I erase the fault code, and go for a ride, code doesn't come up until I restart the car again (restarting it immediately or a next day doesn't make a difference)

 

[HITECH]

New DPF Sensor is 1st thing you should have changed after completing a regeneration if you knew it wasnt doing it like it should before. The sensor will be caked inside and kick up a limp mode. You would normally get fault codes in the 1400 range pointing to all sorts like MAF and that 2002 has also come up on cars Ive worked on when the DPF sensor was the faulty component. I dont think your diagnostic tool is pulling out the whole story either bud.

 

[vagon]

New DPF Sensor is 1st thing you should have changed after completing a regeneration if you knew it wasnt doing it like it should before. The sensor will be caked inside and kick up a limp mode. You would normally get fault codes in the 1400 range pointing to all sorts like MAF and that 2002 has also come up on cars Ive worked on when the DPF sensor was the faulty component. I dont think your diagnostic tool is pulling out the whole story either bud.

Totally agree, thank you for coming back to me so quickly.

Bosch one is around £35 and swap is 5mins tops. So will change it and post the result, hopefully will be fixed.

 

[HITECH]

Bosch is a good make ok but when it comes to these sensors. Im serious when I say get a genuine mercedes ones. I have found people replacing them for cheaper versions and also Bosch ones and what happens it might even work for a day or 2 but then starts kicking up completely different faults which adds to the confusion. A genuine mercedes one will guarantee you peace of mind. If you already bought the bosch one then hopefully you get a decent one. Even if your present one is not yet faulty, it will not have much life left in it going by the faults your having. Im hazarding a experienced guess its faulty tho. The faults you describe have to be trouble shot in a certain order to get to the bottom of things. Do another regen with the new dpf sensor when u fit it.

Totally agree, thank you for coming back to me so quickly.

Bosch one is around £35 and swap is 5mins tops. So will change it and post the result, hopefully will be fixed.

 

[vagon]

Thanks a lot for the support HITECH. Differential Pressure Sensor arrived (updated part number A0061539528), fitted it and car is finally healthy. DPF soot is at levels 4 of 9, so regeneration has not happen yet (can't do a forced regen as my Autel MK808 is not supporting it for some reason). But Pressure sensor is showing finally what it should.

Engine OFF 0-1hPa
Idle 7hPa
Cruising up to around 50hPa
Flat out around 120hPa

No limp mode anymore, no errors. Car very smooth and full power, gave a it an hour test drive. Very happy now !

P.S.Just before I fitted the new sensor I checked the exhaust values one more time, and DPF pressure sensor was showing negative values between -48 to -15.

 

[HITECH]

Thats brilliant news bud. Wouldnt worry too much about dodgy readings if its running ok. If you can get all codes deleted and a regeneration completed its the main thing. Then give your car a full service weither its had a service a few months ago or not. Start new with the new sensor m8. Thats all I can say then its happy days. Get your oil changed ASAP and new oil filter !

Thanks a lot for the support HITECH. Differential Pressure Sensor arrived (updated part number A0061539528), fitted it and car is finally healthy. DPF soot is at levels 4 of 9, so regeneration has not happen yet (can't do a forced regen as my Autel MK808 is not supporting it for some reason). But Pressure sensor is showing finally what it should.

Engine OFF 0-1hPa
Idle 7hPa
Cruising up to around 50hPa
Flat out around 120hPa

No limp mode anymore, no errors. Car very smooth and full power, gave a it an hour test drive. Very happy now !

P.S.Just before I fitted the new sensor I checked the exhaust values one more time, and DPF pressure sensor was showing negative values between -48 to -15.

 

[vagon]

That's exactly the next thing to do, full service = all filters and oil.

Again, thanks a lot for the support !