OM642 ML 2010 - DPF will go into regeneration repeatedly, even with 0% soot and ash content?

[endofmytether]

Hi all,

I’m really hoping someone here can help, in fact I pray someone can.

It seems the garages are baffled, even I’m being robbed or it’s just a tricky issue. So after spending so much trying to sort without success I’ve resorted to trying to figure it out myself, get clued up. I’ve dabbled in doing diy on cars, so know a thing or two, but this stumps me.

So as the title goes the car will finish its regen successfully and drive perfectly, until you switch off the ignition leave for a while and restart, then it raises revs to around 900rpm and starts its dpf cycle again.

I’ve had the following items replaced/ repaired with original Mercedes parts:

-DPF taken off and cleaned professionally with a machine.
- new pressure differential sensor
- Oil cooler seals replaced, as I thought this may be a factor, at the same time I got all associated seals replaced turbo seal etc, air filter changed service oil.
- PCV valve
- Fuel filter
- new EGR valve

I have installed xentry, and have been interrogating my vehicle with this, to try and find the root of the issue. Actually, as it’s 2010 I think it uses the DAS program, rather than xentry. I believe .

Anyhow, before this all kicked off I was getting the error code 13AF00 regeneration frequency too high, well that figures.

So interrogated this code with DAS, and gave me some instructions to re teach the dpf like it has had a new CDI unit, change the oil as it may be contaminated, and also test the values of the sensors to see if they are out of range. I tested the temp sensors before and after, and they came back within range.

The only one perhaps that I’m not sure is the upstream o2 sensor. I have attached my screen shots. Xentry was flashing on the “NO” button like it was trying to hint it was out of range, but the figure looks right? Could this be the problem, and show no fault code for it?

Is this sensor perhaps the cause of my DPF going into regen all the while, and filling with soot quickly. The two have to be related.

I’m also desperate to find the DPF log but can’t find it anywhere. I go to Control units > drive > common rail diesel injection > actual values > Deisel particulate filter .

Then I just get the live values of the DPF? and not the historic info?

If you got this far, thanks for reading. Hopefully some of you kind people can help me out, I’m well, at the end of my tether.

Cheers

Al

 

[endofmytether]

These images below are taken when it was doing one of its erroneous dpf regens, with no soot, and no ash. Looking at it now, I see that upstream of TWC gives a value of 4.0. This, could mean that engine has excess air, according to text on a previous window.

 

[ajlsl600]

If ur dpf is doing regen when not full? The sensor measuring the differential pressure must be telling fibs to the ecu or there's a problem with the wiring causing info errors I don't know the values correct or otherwise, but if the values are correct( in specc) and Yr dpf continues to do unrequsted dpf regen then I would suspect wiring(poor connection or short?) or a bug in the ecu.is there anything like a. Teach in for a replacement dpf on xentry?
Do wait for others, many who will know far more than I on this matter

 

[endofmytether]

If ur dpf is doing regen when not full? The sensor measuring the differential pressure must be telling fibs to the ecu or there's a problem with the wiring causing info errors I don't know the values correct or otherwise, but if the values are correct( in specc) and Yr dpf continues to do unrequsted dpf regen then I would suspect wiring(poor connection or short?) or a bug in the ecu.is there anything like a. Teach in for a replacement dpf on xentry?
Do wait for others, many who will know far more than I on this matter

Hi, thanks for your reply, I’ve tried the teach in the dpf via xentry, and this has not helped, and also air filter teach in after I changed, also I have told the system the dpf is new, which it sort of is after it was cleaned, as 0% ash content.

The pressure sensor has been changed, and I did the diagnostic procedure on this sensor, and other associated sensors etc which came back within range, the only one which was sketchy is perhaps for the lambda before TWC as per images. Even though the figures looked right to me, xentry was flashing green on the no button, hinting the figures were wrong.

Like you say perhaps there is a wiring fault, this is something I will have to get checked out as I’m not confident prodding with a multi meter, nonetheless I’ll have a look at the pressure sensor connector for corrosion. But the thing is when I check the pressure back pressure all seems normal at idle, and the figure increases when more soot is building as you would expect with more back pressure.

Perhaps it’s a software bug? I’m tempted to take it to Mercedes to have the dreaded software update recall, that it has not had yet, in the hope flashing the software might clear it of its software related.

At a bit of a loss with this one really. I’ve booked to have it in the merc garage anyway for a specialist diagnosis at £170 so perhaps they might shed some light but I’m not hopeful.

 

[ajlsl600]

I wud reccomend an indie as known on here. Do the diagnostics then unless it's really simple get away from the dealer and personally a software update wud be last option. Unless good indie. Suggests otherwise? Good luck.

 

[endofmytether]

Thanks , do you there any recommendations for someone around Devon, or the perhaps the south, even if there’s a bit of travel for the right person to diagnose would be worth it?

 

[mioba]

wilding motors - paignton.

 

[ajlsl600]

There's also a well known indie at Avonmouth, Bristol.

 

[mibo]

Will be interested in what your issue is as I don't think cleaning mine is going to resolve it.

 

[M80]

If you're getting good readings I wouldn't expect a wiring fault.
V similar but you may have an intermittent connection issue at a sensor or ECU. Wiggling wires might show that, otherwise a blip while monitoring live data might show that.

Be cautious probing the plugs with a meter. The blades can flare resulting in the intermittent fault I described.

Can you be sure that oil isn't being sent into the exhaust, that'd create a regen effect.

Check for brittle wiring around the exhaust. Mine had DP wiring that had been in contact with the exhaust, and cooked it. Result, it sporadically shorted.

 

[Marshall007]

Hi there,
did you manage this problem somehow?
I have same car, ML350, same year 2010, same engine and SAME PROBLEM
I investigate is around half year, also by Xentry looking on sensors, replace all what you replaced and nothing change.
I have also this strange value [220...260] Internal resistance G3/2 (O2 sensor upstream of KAT): 300 Ohm

 

[Wighty]

Hi there,
did you manage this problem somehow?
I have same car, ML350, same year 2010, same engine and SAME PROBLEM
I investigate is around half year, also by Xentry looking on sensors, replace all what you replaced and nothing change.
I have also this strange value [220...260] Internal resistance G3/2 (O2 sensor upstream of KAT): 300 Ohm

I think the op was a one hit wonder , he’s not been back on the forum .
Maybe start your own thread might help ?

 

[Marshall007]

I think the op was a one hit wonder , he’s not been back on the forum .
Maybe start your own thread might help ?

maybe u are right

 

[endofmytether]

Hi, but if a late update, so unfortunately after loads of different diagnosis and £ spent, I never got to the bottom of what was causing this issue, so for the moment I’m just living with it. I might have another crack at a later date. I’d be interested if anyone else found a solution.