DPF Regeneration In Process and P242F code (Long)

[2013megacab]

I was on the way to an appointment the other day when the truck put up the message that the DPF was 100% full and a regeneration was in progress. I have seen this a few times before, so I wasn't particularly concerned, but I had to interrupt it for the appointment. When I came out I started the truck and drove it, intending to let it complete. It seemed like it was taking longer than usual; I thought higher temperatures might be needed so I dropped the gear lower to get the RPMs up over 2000. A few seconds later I got a MIL. I drove home with no progress on the regeneration.

I got out my code reader and found three iterations of P242F, excessive ash level in the DPF with the last being a permanent code, but no other codes. Googling revealed a lot of information; several posts stated that once the code sets permanent, the truck would not allow a regeneration cycle until the code was cleared by a shop with an appropriate diagnosis system. I called my shop and asked if I could drive the truck for short distances to tow my trailer to the storage lot and then bring it in for diagnosis. Since they said no problem, I hooked up the trailer and towed it about 6 blocks. While hooking up and unhooking I let the engine idle a lot, but finally shut it down to avoid potential for the dreaded limp mode. All this time the MIL was illuminated.

When re-started the truck, the MIL was gone. The truck indicated it was still in the Regeneration Cycle so I thought I'd drive it a while. Just when I started to figure that it was not going to improve and prepared to turn around and go home, the full level dropped to 90%. On the way home it continued to drop - 80, 70, 60, and then messaged Regeneration Cycle Complete.

So, after all this, do I have a problem still lurking, waiting to find the most inconvenient time to raise its head, or am I good?

 

[Hoefler]

The idling is causing your problem. Never, I mean never let it idle longer than to let the oil pressure come up! If you have to idle it, use the idle up feature using the cruise control and get the RPMs up to 1500. Working the engine hard will keep the DPF clean. Get it hot and keep it there!

 

[AH64ID]

Raising the rpms is also counterproductive, as the lower gear means the engine doesn’t have to work as hard and there is increased airflow. Both lead to lower exhaust temps, not higher.

Monitoring my EGT’s with a CTS3 the lower the rpms the better the active regen is. Once the regen is complete and the exhaust is still hot I’ve then found a quick high boost/rpm run to be a good thing.

As mentioned you should idle these trucks as little as possible. More than 10 minutes per hour of operation is considered excessive by Cummins, that’s 16.7% if you compare your idle hours to total hours.

Diesels got the reputation of liking to idle all day when they were hard to start, it’s always been less than ideal for them and now with the emissions equipment it’s even worse.

If that trailer has any weight to it, go get it and drive interstate speeds for 30 minutes, turn around and go put it back in storage.

 

[Turbo Terry]

Very hard to not do some idling in a cold climate. I’m trying real hard not to but still I’m doing 19-20 percent idle time

 

[2013megacab]

In this case I was idling because I was getting out to check trailer alignment and getting back in to adjust several times, although in the past I have probably idled too much when traveling to keep dogs comfortable when stopped.

 

[sag2]

You should be able to idle a properly running 2013 for almost as long as you want. They integrated net zero software early on that vastly improved the sooting at idle. The 2013+ trucks should be much better than the 2007-2012 trucks. I'm not saying you should, but a properly running truck can do a considerable amount of idling without plugging the DPF.

 

[AH64ID]

You should be able to idle a properly running 2013 for almost as long as you want. They integrated net zero software early on that vastly improved the sooting at idle. The 2013+ trucks should be much better than the 2007-2012 trucks. I'm not saying you should, but a properly running truck can do a considerable amount of idling without plugging the DPF.

Doesn’t it take 2 hours of idling to get into that mode? Seems way too long to be beneficial, but that’s what the owners manual says.

 

[sag2]

Net zero should be the strategy the ECM uses to try and keep the soot level from rising at idle. It will usually come up a few grams on a truck in good condition, but should start to drop as soon as you start driving again.

 

[AH64ID]

Net zero should be the strategy the ECM uses to try and keep the soot level from rising at idle. It will usually come up a few grams on a truck in good condition, but should start to drop as soon as you start driving again.

Is there anything written on net zero and net reduction for the newer trucks. The last thing I recall on them was the TSB from 2008, and info around that time.

I recall my buddies 2010 going into it, but have never seen a 13+ engine do the same.

The current owners manual states…

If the engine is allowed to idle or the truck is driven on low engine speed drive cycles for more than two hours, the system will automatically enter an emissions operating mode that will increase the engine idle speed to 900 RPM. While in this mode, which is designed to help maintain the diesel particulate filter, the engine idle speed will return to normal when the brake pedal is applied. A small change in engine tone or a slight change in engine performance while accelerating may also be noticeable at speeds below 20 mph (32 km/h). This operating mode may last for up to an hour of idle time, or around 20 minutes of driving time.

 

[Diesel85]

Is there anything written on net zero and net reduction for the newer trucks. The last thing I recall on them was the TSB from 2008, and info around that time.

I recall my buddies 2010 going into it, but have never seen a 13+ engine do the same.

The current owners manual states…

If the engine is allowed to idle or the truck is driven on low engine speed drive cycles for more than two hours, the system will automatically enter an emissions operating mode that will increase the engine idle speed to 900 RPM. While in this mode, which is designed to help maintain the diesel particulate filter, the engine idle speed will return to normal when the brake pedal is applied. A small change in engine tone or a slight change in engine performance while accelerating may also be noticeable at speeds below 20 mph (32 km/h). This operating mode may last for up to an hour of idle time, or around 20 minutes of driving time.

This is an interesting topic. I notice on my 2020 Cummins that I drive, if I idle it for a long time >2 hours it it doesn't do anything. The longest I've ever idled that truck was about 6 hours and if I recall, the idle never changed. However, I believe as soon as I started driving it, the truck began a regeneration. Normally it doesn't get idled for no more than 20-30 minutes (maybe once a month), but typically/mostly no more than 5 minutes. I get in and go and turn off as needed.

However, the Ford Powerstrokes, if they sit and idle for more than 15 minutes, they automatically raise the idle to ~1000 rpms and will stay there if the DPF is over 50%.

Interesting strategies on how these manufacturers deal with soot loading. Should be considered when purchasing a modern diesel to fully understand how the regeneration strategies work, because in the end game, it typically means more fuel getting used to clean the DPF. Which in the long run, costs the end user money in higher fuel usage.

 

[sag2]

I don't recall seeing anything in writing recently concerning net zero, but the OM reference you gave is probably the best indication that they are trying to minimize soot load while still providing excessive idle time for those few people that need it. We have come a long way since 2007.

 

[slowmover]

Very hard to not do some idling in a cold climate. I’m trying real hard not to but still I’m doing 19-20 percent idle time

Genuine Mopar Cover, Front End 82215749AC

Keep the heat exchanger stack insulated.

DIY if nothing else.

.

 

[bcbender]

I've been considering that cover, I never had one because in NC we don't have a lot of days below 0C (32F)... I also now have a company van and don't drive the truck enough (sadly).. What is the benefit (or need) in my case? I would say I only drive it "occasionally" when cold, I actually now try to keep it off the road during inclement weather to avoid the brine they apply every time the weatherman says there's a chance of frozen anything....

I used to let my 04 warm for a few min on high idle before leaving, now on the 20 I let it warm till the temp is over 100, then go slowly in TH mode to get it warmed up as quickly as possible under light load, but again I don't drive it regularly anymore. I do have the block heater I will use if I know I am driving it and its going to be below 5C (40F)

 

[Cummins12V98]

Never have I warmed up an engine. Start, let oil pressure build, put in gear and take it easy for a bit. Always had excellent oil reports.

 

[AH64ID]

The winter front helps retain heat in the engine bay, which is good for the engine, exhaust, and all your emissions components.

Personally I wouldn’t use tow haul for warmup. I want the rpms lower until it’s all warmed up. TH will likely make it take longer to warm up too.

Never have I warmed up an engine. Start, let oil pressure build, put in gear and take it easy for a bit. Always had excellent oil reports.

That’s best practice for a diesel.

Not saying I’ve never let it idle, but it’s not part of the routine.

 

[Turbo Terry]

So this dpf thing is rather new to me. In 22 k miles on my 2022 I have only seen the dpf gauge at 25 per cent one time that I remember .Not that I watch it all the time but just saying. is this good or bad. I need a bit of explaining

 

[slowmover]

So this dpf thing is rather new to me. In 22 k miles on my 2022 I have only seen the dpf gauge at 25 per cent one time that I remember .Not that I watch it all the time but just saying. is this good or bad. I need a bit of explaining

Consumption per 1000-miles is easiest metric. Your mix of driving against fixed factors is the thing (vehicle spec, climate, topography). Engine idle time, plus engine hours below op-temp, are what to limit.

Track against Average MPH.
(Trips under 45-miles are severe service especially under no load).

The ideal is oil temp has gotten above 200F and one has been steady-state 45-MPH or higher for over an hour. That’s where warm-up is “done”. (Internal engine friction + rolling resistance now minimal).

Past this is where fuel burn is potentially lowest. DEF use falls way off at this point. Record what percentage of your engine hours fall into this category.

(Whatever you can do to shorten warm-up from cold — which is 4-hours — is to your benefit).

Americans go to 90% of the same places 90% of the time. It won’t be hard to categorize what you do to “see” where your trips are optimal in length, and where they aren’t. DEF burn will parallel strongly (trip mix over 1k miles).

Average MPH understood against Average MPG is predictive: I don’t have to look at the DEF gauge in a big truck to know how much that 20/gal tank will take.

.

 

[AH64ID]

So this dpf thing is rather new to me. In 22 k miles on my 2022 I have only seen the dpf gauge at 25 per cent one time that I remember .Not that I watch it all the time but just saying. is this good or bad. I need a bit of explaining

That’s a good thing, that means your average use is producing enough passive regen to keep the DPF clean and on its 24 hour based active regen cycle instead of a soot loading based regen cycle.

If you look at steady state, not instant, mpg’s then this is what I see by monitoring additional parameters with my CTS3.

At 22+ mpg there isn't any passive regen, 18-22 mpg is more of a net neutral, and anything less than 18 mpg will have continuous passive regen. Below 12 mpg and you're cleaning it failry quickly.

 

[slowmover]

Below 12 mpg and you're cleaning it failry quickly.

Meaning Solo/Empty or Loaded/Towing?

 

[AH64ID]

Below 12 mpg and you're cleaning it failry quickly.

Meaning Solo/Empty or Loaded/Towing?

Doesn’t matter, the EGT’s associated with sub 12 mpg driving are sufficient to rapidly clean the DPF or keep it clean.