question about DPF

[TNmountainman]

Without a load 75 mph may not be enough heat for a good passive regen if the filter is full. I often see passive regen at 75, but also often don’t see much if it’s slightly downhill or with a tailwind. 18-20 mpg won’t do much for passive regen, but also doesn’t fill the filter.

You’ll want to get your average mpg down below 15 for an hour or two to get a really good passive regen, below 12 would be better.

Got a trailer you can tow?

yes. yes I do. I have one that weighs 7000lbs and probably has about 8000 in logs sitting on it right now. I can also easily put my 13,000lb skid steer on my equipment trailer and haul that.
The problem is, that won’t clear the code. From what i have been reading (and learning), the P242F code means the ECM thinks the DPF is full of ash. Which based on another users speculation, is really soot that has accumulated from 2 straight months of one mile trips to a jobsite I have been making 3 times a day without ever having a chance to burn off.
Once the P242F code is active, it literally cannot be turned off without computer reset of different things like the DPF timer data, and such.
So that’s my next plan of attack, to try and go in with AlphaOBD and a security bypass gateway and reset everything and then perform an active regen and see what happens.

 

[TNmountainman]

My dealer replaced my entire DPF last week. I brought it in for an engine light with 1200 miles on it. They pulled the truck and said excessive soot in tailpipe and the DPF wasn't doing its job...

it seems like the dealerships are ill-equipped to properly diagnose these issues and just swapping out the DPF is what they do because it works.

 

[AH64ID]

yes. yes I do. I have one that weighs 7000lbs and probably has about 8000 in logs sitting on it right now. I can also easily put my 13,000lb skid steer on my equipment trailer and haul that.
The problem is, that won’t clear the code. From what i have been reading (and learning), the P242F code means the ECM thinks the DPF is full of ash. Which based on another users speculation, is really soot that has accumulated from 2 straight months of one mile trips to a jobsite I have been making 3 times a day without ever having a chance to burn off.
Once the P242F code is active, it literally cannot be turned off without computer reset of different things like the DPF timer data, and such.
So that’s my next plan of attack, to try and go in with AlphaOBD and a security bypass gateway and reset everything and then perform an active regen and see what happens.

Once you get the code cleared with AlfaOBD and do an initial stationary desoot I would tow the heavy trailer for a couple hours at interstate speeds.

it seems like the dealerships are ill-equipped to properly diagnose these issues and just swapping out the DPF is what they do because it works.

Generally it will have the opposite effect as the airflow increases and the load decreases so the DPF temp is lower.

 

[mbarber84]

My dealer replaced my entire DPF last week. I brought it in for an engine light with 1200 miles on it. They pulled the truck and said excessive soot in tailpipe and the DPF wasn't doing its job...

Excessive soot in the tailpipe would indicate a compromised DPF. The media is cracked inside, or the pressure vessel is breached. It’s letting soot-laden exhaust pass directly through without being filtered. This is where the Particulate Matter sensor would trigger an alert if it was installed. Is your truck a 2022?

 

[mbarber84]

it seems like the dealerships are ill-equipped to properly diagnose these issues and just swapping out the DPF is what they do because it works.

Swapping in a fresh DPF can sometimes fix the issues, if the DPF itself was directly responsible for the failure. As stated in the STAR documentation I shared earlier in this thread, dealers have been seeing several DPF’s fail internally. Either pieces of the material fall apart and block the inlet, or the filter is somehow breached. Unfortunately, many dealerships are not equipped to diagnose or handle this issue and they revert to putting a new DPF on as a means to get the truck back to the owner. This only serves to kick the can down the road. If the primary point of failure is an upstream issue, the new DPF will only last so long.

 

[TNmountainman]

Excessive soot in the tailpipe would indicate a compromised DPF. The media is cracked inside, or the pressure vessel is breached. It’s letting soot-laden exhaust pass directly through without being filtered. This is where the Particulate Matter sensor would trigger an alert if it was installed. Is your truck a 2022?

 

[TNmountainman]

it’s a 2019 with 47k miles. It is throwing a P242F code (senses an ash build-up which is impossible at 47K). A post earlier that I think is correct, is that soot buildup due to incomplete regen cycles has triggered a false interpretation of the sensors by the ECM which caused the P242F code.

 

[mbarber84]

it’s a 2019 with 47k miles. It is throwing a P242F code (senses an ash build-up which is impossible at 47K). A post earlier that I think is correct, is that soot buildup due to incomplete regen cycles has triggered a false interpretation of the sensors by the ECM which caused the P242F code.

Yeah that was my theory. I think that’s what causes it. A lot of incomplete or interrupted regeneration cycles.