question about DPF

[Dodgeman]

If you’re getting the filter full message, that could be due to DTC P242F being active.
P242F means the truck sees the particulate filter is full, and is estimating that the blockage is a result of ash.

There are two compounds that will “fill” a DPF.

Soot and ash.

Nice explanation. Thanks.

 

[mbarber84]

dude! that is a great reply! Thank you for taking the time to provide more insight and knowledge!
I guess one question that I’m wondering is that isn’t 47000 miles considered low mileage and that it is unlikely the ECM is thinking it is the DTC P242F error?
Also, how can I find this exact error code?

47,000 miles would be ridiculously early in a DPF’s life cycle to be ash restricted. You’d have to be doing some things egregiously wrong. Or have a major failure of some sort. I suspect (key word) that these trucks can get confused when they regularly are not seeing fully successful regenerations. I have some theories on this but I don’t have the time or the resources to “test”.

These trucks will pause a regen cycle if the truck is put in park or shut off. It'll pick back up when the truck begins to move again. However, quite often, the conditions inside the DPF are different than when it began the cycle. Temps may be lower, drive cycle may be different, etc. So I think you don’t get as effective a “burn out” if the regeneration is interrupted. If this becomes a habit, I think you end up with build ups that the truck sees as “ash” when in reality it’s soot. Build up after build up, just causes more of the same. Ultimately the truck pops P242F thinking there’s too much ash restriction when there really isn’t. Once that sets, active regen won’t work anymore because the truck inhibits it. The trucks that are routinely driven in stop and go, or low speed short cycle operation, seem to be most at risk for this. Since there’s no outward notification to the driver that a cycle is running, they can inadvertently interrupt regen cycles if they aren’t paying attention. (Yes you can see the message if you keep it on the DPF screen, but the average driver doesn’t do that. In fact, most people don’t even look at the page)

 

[20Limited3500]

47,000 miles would be ridiculously early in a DPF’s life cycle to be ash restricted. You’d have to be doing some things egregiously wrong. Or have a major failure of some sort. I suspect (key word) that these trucks can get confused when they regularly are not seeing fully successful regenerations. I have some theories on this but I don’t have the time or the resources to “test”.

These trucks will pause a regen cycle if the truck is put in park or shut off. It'll pick back up when the truck begins to move again. However, quite often, the conditions inside the DPF are different than when it began the cycle. Temps may be lower, drive cycle may be different, etc. So I think you don’t get as effective a “burn out” if the regeneration is interrupted. If this becomes a habit, I think you end up with build ups that the truck sees as “ash” when in reality it’s soot. Build up after build up, just causes more of the same. Ultimately the truck pops P242F thinking there’s too much ash restriction when there really isn’t. Once that sets, active regen won’t work anymore because the truck inhibits it. The trucks that are routinely driven in stop and go, or low speed short cycle operation, seem to be most at risk for this. Since there’s no outward notification to the driver that a cycle is running, they can inadvertently interrupt regen cycles if they aren’t paying attention. (Yes you can see the message if you keep it on the DPF screen, but the average driver doesn’t do that. In fact, most people don’t even look at the page)

I just went through this with my '20. Got the Exhaust Filter full message with P242F code at just under 46K miles last month. 10k since I had Y78 recall done. Got it into dealer 2 weeks later and they determined DPF was faulty and needed replaced. Thankfully it was still under the 7/70 emissions warranty and it all was covered. I used to drive my truck daily to and from work, 6 miles each way. Obviously I wasn't getting it up to proper temps doing this. I now have a commuter I picked up last year so I don't regularly drive it like that anymore. And I won't from now on after getting the DPF replaced. I did notice that after the Y78 recall with reprogram the regens seemed to happen more often. Like every 6 hrs it seemed. I did complain about that when I took it in. Paperwork stated they reprogrammed before determining DPF was faulty. But I don't know what that reprogram did. I have taken truck on a trip since this past weekend and did not experience the excessive regens like I was having before. I will keep an eye on it the more I drive it as time goes to see.

 

[TNmountainman]

47,000 miles would be ridiculously early in a DPF’s life cycle to be ash restricted. You’d have to be doing some things egregiously wrong. Or have a major failure of some sort. I suspect (key word) that these trucks can get confused when they regularly are not seeing fully successful regenerations. I have some theories on this but I don’t have the time or the resources to “test”.

These trucks will pause a regen cycle if the truck is put in park or shut off. It'll pick back up when the truck begins to move again. However, quite often, the conditions inside the DPF are different than when it began the cycle. Temps may be lower, drive cycle may be different, etc. So I think you don’t get as effective a “burn out” if the regeneration is interrupted. If this becomes a habit, I think you end up with build ups that the truck sees as “ash” when in reality it’s soot. Build up after build up, just causes more of the same. Ultimately the truck pops P242F thinking there’s too much ash restriction when there really isn’t. Once that sets, active regen won’t work anymore because the truck inhibits it. The trucks that are routinely driven in stop and go, or low speed short cycle operation, seem to be most at risk for this. Since there’s no outward notification to the driver that a cycle is running, they can inadvertently interrupt regen cycles if they aren’t paying attention. (Yes you can see the message if you keep it on the DPF screen, but the average driver doesn’t do that. In fact, most people don’t even look at the page)

dang, I don’t know why I missed this reply. Yes, I am thinking I could try resetting the codes, force it to do a regen, then “maybe” all should be good? Does it have to be moving to do an active regen or can the ECM initiate one while it is sitting?

 

[TNmountainman]

I just went through this with my '20. Got the Exhaust Filter full message with P242F code at just under 46K miles last month. 10k since I had Y78 recall done. Got it into dealer 2 weeks later and they determined DPF was faulty and needed replaced. Thankfully it was still under the 7/70 emissions warranty and it all was covered. I used to drive my truck daily to and from work, 6 miles each way. Obviously I wasn't getting it up to proper temps doing this. I now have a commuter I picked up last year so I don't regularly drive it like that anymore. And I won't from now on after getting the DPF replaced. I did notice that after the Y78 recall with reprogram the regens seemed to happen more often. Like every 6 hrs it seemed. I did complain about that when I took it in. Paperwork stated they reprogrammed before determining DPF was faulty. But I don't know what that reprogram did. I have taken truck on a trip since this past weekend and did not experience the excessive regens like I was having before. I will keep an eye on it the more I drive it as time goes to see.

can you elaborate on this 7/70 emissions warranty? I have seen both yes and no answers concerning the DPF.

 

[mbarber84]

dang, I don’t know why I missed this reply. Yes, I am thinking I could try resetting the codes, force it to do a regen, then “maybe” all should be good? Does it have to be moving to do an active regen or can the ECM initiate one while it is sitting?

You can force it to do a stationary despot (aka parked regeneration) if you have the proper scan tool. The only way to get it to do an active regeneration is based on the engine timer or the soot load in the DPF. If it’s near 50% full it will trigger a regeneration once it’s up to speed and hot enough. Active regeneration only happens when the truck is moving, or if the parked regeneration is initiated by the proper scan tool.

 

[TNmountainman]

I just went through this with my '20. Got the Exhaust Filter full message with P242F code at just under 46K miles last month. 10k since I had Y78 recall done. Got it into dealer 2 weeks later and they determined DPF was faulty and needed replaced. Thankfully it was still under the 7/70 emissions warranty and it all was covered. I used to drive my truck daily to and from work, 6 miles each way. Obviously I wasn't getting it up to proper temps doing this. I now have a commuter I picked up last year so I don't regularly drive it like that anymore. And I won't from now on after getting the DPF replaced. I did notice that after the Y78 recall with reprogram the regens seemed to happen more often. Like every 6 hrs it seemed. I did complain about that when I took it in. Paperwork stated they reprogrammed before determining DPF was faulty. But I don't know what that reprogram did. I have taken truck on a trip since this past weekend and did not experience the excessive regens like I was having before. I will keep an eye on it the more I drive it as time goes to see.

can you elaborate on this 7/70 emissions warranty? I have seen both yes and no answers concerning the DPF

You can force it to do a stationary despot (aka parked regeneration) if you have the proper scan tool. The only way to get it to do an active regeneration is based on the engine timer or the soot load in the DPF. If it’s near 50% full it will trigger a regeneration once it’s up to speed and hot enough. Active regeneration only happens when the truck is moving, or if the parked regeneration is initiated by the proper scan tool.

yea, that’s what I want to do, clear the codes then run an active regen. They make it harder than it should be, gotta do the gateway bypass and have to remove the instrument panel to get to it.

 

[TNmountainman]

47,000 miles would be ridiculously early in a DPF’s life cycle to be ash restricted. You’d have to be doing some things egregiously wrong. Or have a major failure of some sort. I suspect (key word) that these trucks can get confused when they regularly are not seeing fully successful regenerations. I have some theories on this but I don’t have the time or the resources to “test”.

These trucks will pause a regen cycle if the truck is put in park or shut off. It'll pick back up when the truck begins to move again. However, quite often, the conditions inside the DPF are different than when it began the cycle. Temps may be lower, drive cycle may be different, etc. So I think you don’t get as effective a “burn out” if the regeneration is interrupted. If this becomes a habit, I think you end up with build ups that the truck sees as “ash” when in reality it’s soot. Build up after build up, just causes more of the same. Ultimately the truck pops P242F thinking there’s too much ash restriction when there really isn’t. Once that sets, active regen won’t work anymore because the truck inhibits it. The trucks that are routinely driven in stop and go, or low speed short cycle operation, seem to be most at risk for this. Since there’s no outward notification to the driver that a cycle is running, they can inadvertently interrupt regen cycles if they aren’t paying attention. (Yes you can see the message if you keep it on the DPF screen, but the average driver doesn’t do that. In fact, most people don’t even look at the page)

 

[TNmountainman]

I agree with your theory. Would it stand to reason that by driving on the freeway for an hour at 75MPH or having it sit for 60 minutes at 2500RPM would effectively burn the soot out (passive regen), and once that has been accomplished use a scan tool to reset the P242F code and it should be good to go?

 

[mbarber84]

I agree with your theory. Would it stand to reason that by driving on the freeway for an hour at 75MPH or having it sit for 60 minutes at 2500RPM would effectively burn the soot out (passive regen), and once that has been accomplished use a scan tool to reset the P242F code and it should be good to go?

If P242F is set, the system might inhibit an active regeneration. If you can get the truck up to temperature with a load on it, you may be able to get it to passively regenerate enough but there’s no guarantee.

I highly recommend taking a little time and reading this thread. The author experienced a similar situation and is very knowledgeable in the system.

P242F - what I've learned

www.cumminsforum.com

 

[flan]

can you elaborate on this 7/70 emissions warranty?

It’s in your owners manual

 

[mbarber84]

It’s in your owners manual

The 7 / 70 emissions warranty does not apply to every state. The truck has to be registered in one of the States listed under the “California Emissions Warranty” in order to qualify for the 7 / 70.

For everyone outside of those states, it’s 5 / 50

 

[flan]

The 7 / 70 emissions warranty does not apply to every state. The truck has to be registered in one of the States listed under the “California Emissions Warranty” in order to qualify for the 7 / 70.

For everyone outside of those states, it’s 5 / 50View attachment 66738View attachment 66739

The info on his emissions warranty is in his owners manual.

 

[TNmountainman]

The 7 / 70 emissions warranty does not apply to every state. The truck has to be registered in one of the States listed under the “California Emissions Warranty” in order to qualify for the 7 / 70.

For everyone outside of those states, it’s 5 / 50View attachment 66738View attachment 66739

so 2019 with 47K might still be under warranty

 

[mbarber84]

so 2019 with 47K might still be under warranty

Potentially. Depending on what state you’re registered in.

 

[20Limited3500]

Sorry, just got back to this. As stated, it depends on what state and if it is under the "California Emission Warranty". I am in Washington state, so thankfully mine was covered. One of the few good things these days being in Washington state.

Even with the Federal at 5/50, I would think the DPF should be covered. If it weren't for the EPA, these trucks wouldn't have all this crap on them. And EPA is all federal.

 

[phatboy64]

My dealer replaced my DPF under warranty when my truck was a few month old. I had a P2002 DPF efficiency below threshold bank 1 error

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[AH64ID]

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?

 

[Dfdlamson52]

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...

 

[phatboy64]

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?

Would locking out 6th or 5th on the HW to get more RPMs help?