Another DPF confusion - Code: Particulate filter is too high for regeneration

NCV3

New member
Hello,

I got code 3 days ago: Code: Particulate filter is too high for regeneration - my generic OBDII scanner shows code P0242f.

Current standing: at that moment I had on average 20-21.5 mpg almost every day (without A/C), mixed ride with 5% idleing, half-half cty/hwy. NO oil burn between the changes. No leaks, I do need to top coolant every other week, I would say quart every 25K. Religious maintenance schedule by the book, and earlier, no cutting the corners, all dealer parts and fluids by MB standards. NO loss of power, NO loss in mpg.

1. I've removed dpf than with vacuum, I've sucked unburned particles (from front, that frankly there was no, flow is great, it's nowhere close to clogged, dusted with compressor from the back while having vacuum sucking from front. Try to shake DPF, no clanking, nothing broken inside, lightweight, no buildup.

2. I've removed Complete EGR unit Both valves and egr cooler, there was only soot in radiator, which I've washed for several hours until no black residue would come out of it. Egr valves was completely clear of any residue, only thin wall of carbon, really thin, no ash buildup.

I've try to reset the code, code came back.

3. Went to the MB dealer, dealer performed following procedure:
Attempted to perform regeneration while driving. Vehicle would not let regeneration perform. Performed short test. Found code particulate filter is too high for regeneration. Performed manual regeneration at idle. Found smoke coming PRE DPF (I'm glad they've actually noted this). Check engine light comes back on. Performed full manual regeneration. Cleared codes. Check engine light stays off. Repair complete.

It was OK for 1 day, I noticed 15% lower gas mileage, I would go 18-20 MPG, and I have more power in lower boost.

Than code came back today.

I am not sure where to go from here, my questions:

- If the soot went after EGR cooler (as it was clogged with soot very bad) where it would go? Back egr valve had no soot, What's the part after back EGR valve down stream?

- I know Cat is up stream from DPF, I didn't check CAT, I guess with 345K miles it's time to be replaced. what's above CAT (upstream from CAT)?

- I don't want to guess the parts, I want to pay MB dealer again to diagnose what's needed to be changed, do you have any recommendations/experience what I should know before I go there so I don't be slaughtered (yes, I've read all DPF and P0242f posts on this forum,they all has issues with power, I don't experience).

- When visit MB dealer next time, I'll get printout from DRBIII, what would be helpful to have on hand for future diagnostics, what parameters should I monitor?


Feedback, please

Thanks!!!
 
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talkinghorse43

Active member
I do need to top coolant every other week, I would say quart every 25K.
You can see that I don't have a NCV3, BUT why do you tolerate a continued leak of coolant? Seems to me if coolant is somehow making it's way to the exhaust side, that could foul the DPF in short order.
 

NCV3

New member
Thanks for your reply,

I do not know where to find a coolant leak, when there is no marks, doesn't drip anywhere, I thought it evaporate somehow due to high temperatures. I did start changing all coolant hoses, in last 2 months little by little.

Interesting view, much appreciated.

Thanks
 
If I remember correctly-the site has a digital movie about how a dpf works. I believe the particles are burned and residue forced thru membranes into sides of dpf. I don't believe the vacuum is giving you a thorough cleaning.


gerry
 

NCV3

New member
If I remember correctly-the site has a digital movie about how a dpf works.
I watched it, there is no build up, there is no flow problem.

Full manual DPF cleaned it, but I think the source of the problem is upstream, as smoke comes from pre DPF. I would like to nail the cause of it.

Does anyone has diagram of this part, I am not sure what comes before Catalitic converter, Diagrams show CAT as a first element in exhaust line. Which leads me to question: where is CAT connected to upstream, does anyone has that diagram?
 
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talkinghorse43

Active member
Thanks for your reply,

I do not know where to find a coolant leak, when there is no marks, doesn't drip anywhere, I thought it evaporate somehow due to high temperatures. I did start changing all coolant hoses, in last 2 months little by little.

Interesting view, much appreciated.

Thanks
If small, a coolant leak to the outside could evaporate fast so it wouldn't drip, but it will leave a white-ish residue. If leaking into the engine somewhere, it might be detectable in the exhaust, or in the oil. IIWY, I'd look for some technology to test the exhaust for the presence of coolant and send a sample of the oil to some place like Blackstone to test for coolant.
 

NCV3

New member
I'd look for some technology to test the exhaust for the presence of coolant and send a sample of the oil to some place like Blackstone to test for coolant.
Very cool idea, emailed them for free test kit. Diagnostics are only 25$. Good investment for a piece of mind.
 

piper1

Resident Oil Nerd.
I am not sure what comes before Catalitic converter, Diagrams show CAT as a first element in exhaust line. Which leads me to question: where is CAT connected to upstream, does anyone has that diagram?
The exhaust flow is

Cylinder head, exhaust manifolds, turbo, DOC (the cat), DPF, tailpipe.

Some exhaust is pulled out of the flow above (pre turbo)to be directed to the EGR cooler, then to the EGR valve, to be introduced into the air intake stream for polloution control.

That said, coolant leaking into your exhaust will not improve DPF efficiency. The steam (if it's liquid in the exhaust you have a HUGE leak) will turn the particulates in the DPF into more of a mud than easy to burn dry grit. The DOC will not be effected by coolant contamination enough that it would be the issue, the DPF will be the cause of your worries.

Be sure the coolant IS leaking into the exhaust and not some other gremlin, many of the fixes for it are not cheap or easy.
 

NCV3

New member
The exhaust flow is

Cylinder head, exhaust manifolds, turbo, DOC (the cat), DPF, tailpipe.
Thanks Piper1 for your reply and feedback.

So the only way coolant can steam is in head? I'll diag. coolant in oil first to be sure.
 

talkinghorse43

Active member
So the only way coolant can steam is in head? I'll diag. coolant in oil first to be sure.
Coolant could theoretically get into the exhaust in a number of ways:

- leaking into the egr flow through a hole in the cooler
- leaking into a cylinder through a blown head gasket or cracked head/block
- maybe through a hole in the oil cooler

and probably others.
 

piper1

Resident Oil Nerd.
Thanks Piper1 for your reply and feedback.

So the only way coolant can steam is in head? I'll diag. coolant in oil first to be sure.
Coolant will steam anywhere it encounters enough heat to get above its boiling point. That would include most of the exhaust system.
 

NCV3

New member
I've noticed there is no coolant loss since I washed EGR cooler? It's been 1300 miles since EGR service and not a millimeter drooped from coolant reservoir.

I also noticed 2 different patterns of gas mileage, 21-21.5 mpg sometimes, sometimes 18-19. I guess motor is trying to perform regeneration (unsuccessfully or not in the parameters required) and use much more gas.
 
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jdcaples

Not Suitable w/220v Gen
I don't remember the run-time characteristics required for a passive regeneration cycle to happen.

Below are screen shots from the factory scan tool software, WiTECH, in simulation mode, citing some characteristics required for a manually actuated regeneration cycle.

ECU View -> ECM -> ECM Misc Functions -> Manual Diesel Particulate Filter Regeneration
One.jpg

<Click on that action item>

Two.jpg


I say run it on the highway at over 2000 RPMs for a 30 minutes or so.... if that doesn't clean it out, you're probably looking at some surgery to replace it, or at least a dealership visit for a manual regeneration procedure.
-Jon

PS: The DPF is between the engine and the catalytic converter. You can also measure the resistence on the sensors, according to the Dodge service manual.... 10 ohms.... oh, jus read it for yourself. I'll just screw up the facts with my lack of really understanding this stuff.
 

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piper1

Resident Oil Nerd.
PS: The DPF is between the engine and the catalytic converter.
Other way around Jon, DOC (Cat) first to oxidize as much of the soot as possible and then, DPF to catch what's left....sorry.
 
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jdcaples

Not Suitable w/220v Gen
I posted that while I was staring at the service manual cd content. I've lost it now, but clearly, that's another addition to an errata sheet someone should be keeping (and no, I'm not going to be maintaining an errata sheet).

-Jon

PS: it's in the attachement above (duh)... maybe it should say between the catalytic converter and the muffler

"The Diesel particulate filter is an inline canister filter located in the exhaust system between the engine and the muffler"
 

jdcaples

Not Suitable w/220v Gen
Curiosity got me today. I ran a manual DPF regeneration because I can.

The attached screen shot is what WiTECH software tells the technician after a manual regen is initiated.

I don't think I'll be doing this again, just for the fun of it.

-Jon
 

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suzieque

New member
interesting comment about the oil change....

automatic regens occur at 1212 KM for me, so with a 10000 KM oil change interval I can assume 8 automatic regens before my oil is changed, arguably though they are not consecutive. :)
 

jdcaples

Not Suitable w/220v Gen
interesting comment about the oil change....

automatic regens occur at 1212 KM for me, so with a 10000 KM oil change interval I can assume 8 automatic regens before my oil is changed, arguably though they are not consecutive. :)
The manual regeneration is active, not passive. The regular 1200 km / 700 miles is different from a manual regeneration, I think.

-Jon
 

piper1

Resident Oil Nerd.
Jon is right,

Scan Tool or Shop triggered re-gens are used to correct problems, not as regular maintenance.

The tool triggered re-gens are hotter, use more post injection fuel, and lack the cooling air of driving down the road.

Thus, there is more chance for oil contamination (post injection fuel), and oxidation from higher turbo and general engine oil temps. I think the recommendation however, is overly cautious.
 

suzieque

New member
The tool triggered re-gens are hotter, use more post injection fuel, and lack the cooling air of driving down the road.

Thus, there is more chance for oil contamination (post injection fuel), and oxidation from higher turbo and general engine oil temps. I think the recommendation however, is overly cautious.
good info, I didn't know the tool triggered regens were hotter. The lesson/warnng is that if an owner goes to a dealer for a tool triggered regen, the dealer may charge for an oil change.
 

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