How is your def working in the cold??

[Surgdoc4]

Manual regen doesn’t have anything to do with DEF, nor does the DPF. Dealer likely has no clue, which is unfortunate.

AlfaOBD can do a manual regen and clear codes.

I looked back over your previous posts on this issue, now I get it. Thank you. Are there any preventative measures to avoid the DPF code from appearing, P242F. I use this truck like every other for the past 45 years. Although this is the first with all this emissions BS. The dealer said these trucks can’t be left to idle. That was really not the case despite -15 in MN. It was plugged in and remote started to warm up, that’s it. I will get the AlfaOBD. One more question, sorry, as I have the OBDLink MX+ and the TTXSPP cable adapter, do I still need a security bypass module. Thank you!!

 

[AH64ID]

Yes you still need a security bypass.

Idle it as little as possible, especially cold idle. Even with remote start I don’t let it idle more than 2-3 minutes, normally under 1 minute even sun-zero. Easy driving is the best way to warm up any diesel.

 

[Surgdoc4]

Manual regen doesn’t have anything to do with DEF, nor does the DPF. Dealer likely has no clue, which is unfortunate.

AlfaOBD can do a manual regen and clear codes.

I understand that DEF is unrelated but isn’t a regen, per programming or manual, done to clear the DPF from soot? If neither is this entirely a software/programming/sensor issue where the need for a regen is not recognized early enough or is a code thrown unnecessarily. Where is the failure that precipitates this major problem. It also sounds like the distance to limp mode is random and potentially dangerous. None of this is in the manual. That alone should precipitate legal action.

 

[MEGA HO]

I understand that DEF is unrelated but isn’t a regen, per programming or manual, done to clear the DPF from soot? If neither is this entirely a software/programming/sensor issue where the need for a regen is not recognized early enough or is a code thrown unnecessarily. Where is the failure that precipitates this major problem. It also sounds like the distance to limp mode is random and potentially dangerous. None of this is in the manual. That alone should precipitate legal action.

Correct, the DEF is a separate part of the emission system, DEF is injected downstream of the DPF to reduce the NOx emissions, while the DPF catches soot. Regents are done to burn soot out of DPF. There are 2 sensors that monitor pressure across the DPF and a certain pressure gradient activates the Regen.
I'm not sure major problem you're talking about as DEF issues are unrelated to DPF. DEF system consists of a tank with pump and a heater, lines and injector, any of those could fail and put your vehicle in a limp mode, freezing of DEF is apparently common even though this syst is supposed to be deactivated below certain temperature.

 

[AH64ID]

I understand that DEF is unrelated but isn’t a regen, per programming or manual, done to clear the DPF from soot? If neither is this entirely a software/programming/sensor issue where the need for a regen is not recognized early enough or is a code thrown unnecessarily. Where is the failure that precipitates this major problem. It also sounds like the distance to limp mode is random and potentially dangerous. None of this is in the manual. That alone should precipitate legal action.

Yes regen cleans the DPF, this can be active or passive.

Active regens involve raw fuel being injected into the exhaust stroke. The fuel rich exhaust goes thru the DOC (diesel oxidation catalyst) where it oxidizes and increases temp. The ECM controls the fuel flow to achieve around 1075°F for optimal de-soot in the DPF. The DOC’s proximity to the DPF means the exhaust temp doesn’t drop much between the two. I’ll see post-DPF temps of -1025°-1075° for most of an active regen.

There are three common ways for an active regen to occur. 1) when the DPF is full, or nearing full, from low temp driving. 2) every 24 hours of engine run time, regardless of DPF soot loading. 3) manually, this takes an external input on pickups but some C&C trucks can do it thru the EVIC.

A regularly scheduled 24 hour regen usually takes 10-15 minutes depending on the driving conditions. Raining really seems to slow it down from all the water being splashed on the exhaust for evaporative cooling, and also the biggest reduction in fuel economy I’ve seen during an active regen. The longest I’ve seen this regen take was over 2 hours of run time. In order for an active regen to work the exhaust temp at the DOC inlet has to be a certain temp (not sure what it exactly is, but around 450°F and lower the ecm
wont inject any fuel into the exhaust to be oxidized for regen). I’ve had one regen where I wasn’t keeping the exhaust hot enough for long enough to effectively conduct a regen, but it did eventually finish.

I have no personally experience with a soot loading triggered regen, so I can’t say how long they take. I would guess they can take longer than a 24 hour regen, especially if the DPF is 80%+ full and you get a notification on the EVIC.

Manual regens take 1 hour, and just as a warning the exhaust is HOT. I had leg hairs burned off ~3’ from the exhaust pipe one day.

There is also an active regen that can occur at idle called Net Reduction, and an idle mode called NetZero that both help with soot loading when you can’t get up to highway speed. I haven’t seen Ram/Cummins publish anything on them since they were programmed in the 2008 era (after farm and hunting trucks got stranded from the inability to preform a slow speed regen).

It would be nice if Ram would publish some more info on what it takes to get to an idle regen, but oh well. Not a lot of people having issues with that anymore.

Then there is passive regen. This is anytime you’re working the truck hard enough that the DPF is hot enough to clean. There is lots of different info on what temp this takes, but I have personally seen passive regen start to clean the DPF with DPF outlet temp as low as 600°F. It’s slow at those temps, but does start to clean. Below 600°F and soot starts to accumulate and backpressure increases.

DPF warnings don’t have a mileage countdown, so there isn’t anything to mention in the owners manual about one. Due to the nature of the DPF there isn’t a standard for how long it will last at 80%+ full so there won’t be a countdown. A plugged DPF means no exhaust flow, which can cause engine damage. The 80% full message can happen from driving style, a failed DPF sensor, failed DPF, or a DPF at the end of its service life (usage, improper engine oil, etc). The cause for the message will have a large impact on how long you have until the derate occurs.

DEF warning do have a countdown since DEF malfunctions just impact NOx output and have no impact on engine operation. These are outlined in the owners manual. Personally I think 200 miles isn’t nearly far enough for some of the places I go with my truck, but I didn’t program it.

Probably more than you were asking for, but it’s a nice morning to enjoy the fire and some coffee before the chaos of the day hits.

 

[Surgdoc4]

Yes regen cleans the DPF, this can be active or passive.

Active regens involve raw fuel being injected into the exhaust stroke. The fuel rich exhaust goes thru the DOC (diesel oxidation catalyst) where it oxidizes and increases temp. The ECM controls the fuel flow to achieve around 1075°F for optimal de-soot in the DPF. The DOC’s proximity to the DPF means the exhaust temp doesn’t drop much between the two. I’ll see post-DPF temps of -1025°-1075° for most of an active regen.

There are three common ways for an active regen to occur. 1) when the DPF is full, or nearing full, from low temp driving. 2) every 24 hours of engine run time, regardless of DPF soot loading. 3) manually, this takes an external input on pickups but some C&C trucks can do it thru the EVIC.

A regularly scheduled 24 hour regen usually takes 10-15 minutes depending on the driving conditions. Raining really seems to slow it down from all the water being splashed on the exhaust for evaporative cooling, and also the biggest reduction in fuel economy I’ve seen during an active regen. The longest I’ve seen this regen take was over 2 hours of run time. In order for an active regen to work the exhaust temp at the DOC inlet has to be a certain temp (not sure what it exactly is, but around 450°F and lower the ecm
wont inject any fuel into the exhaust to be oxidized for regen). I’ve had one regen where I wasn’t keeping the exhaust hot enough for long enough to effectively conduct a regen, but it did eventually finish.

I have no personally experience with a soot loading triggered regen, so I can’t say how long they take. I would guess they can take longer than a 24 hour regen, especially if the DPF is 80%+ full and you get a notification on the EVIC.

Manual regens take 1 hour, and just as a warning the exhaust is HOT. I had leg hairs burned off ~3’ from the exhaust pipe one day.

There is also an active regen that can occur at idle called Net Reduction, and an idle mode called NetZero that both help with soot loading when you can’t get up to highway speed. I haven’t seen Ram/Cummins publish anything on them since they were programmed in the 2008 era (after farm and hunting trucks got stranded from the inability to preform a slow speed regen).

It would be nice if Ram would publish some more info on what it takes to get to an idle regen, but oh well. Not a lot of people having issues with that anymore.

Then there is passive regen. This is anytime you’re working the truck hard enough that the DPF is hot enough to clean. There is lots of different info on what temp this takes, but I have personally seen passive regen start to clean the DPF with DPF outlet temp as low as 600°F. It’s slow at those temps, but does start to clean. Below 600°F and soot starts to accumulate and backpressure increases.

DPF warnings don’t have a mileage countdown, so there isn’t anything to mention in the owners manual about one. Due to the nature of the DPF there isn’t a standard for how long it will last at 80%+ full so there won’t be a countdown. A plugged DPF means no exhaust flow, which can cause engine damage. The 80% full message can happen from driving style, a failed DPF sensor, failed DPF, or a DPF at the end of its service life (usage, improper engine oil, etc). The cause for the message will have a large impact on how long you have until the derate occurs.

DEF warning do have a countdown since DEF malfunctions just impact NOx output and have no impact on engine operation. These are outlined in the owners manual. Personally I think 200 miles isn’t nearly far enough for some of the places I go with my truck, but I didn’t program it.

Probably more than you were asking for, but it’s a nice morning to enjoy the fire and some coffee before the chaos of the day hits.

You are a great reference, thank you.

 

[Surgdoc4]

The truck is running fine now. Here is my conclusion, after all the great info provided per AH64ID: The code was a DEF code and countdown warning to limp mode is what occurred. It never did go into limp mode since the countdown never went to zero. I didn’t want to test it given the time and place. A DPF code was never thrown. The DPF gauge read zero, no regen needed per that gauge. The truck had been driven on the interstate at 75 mph for more than 500 miles before the DEF warning. The temp was above 32 degrees at the time but had been below zero for days before and was 5 degrees when the trip started. Truck loaded and towed, by a Chevy no less, for 120 miles. I have good friends. The dealer service manager told me he updated the PCU, did a manual regen, he said the DPF was full but the gauge definitely was at empty, and reset the code. So, maybe the update will help in the future but won’t hold my breath. Clearing the DEF code likely cured the whole problem. My faith in the service department has waned considerably, I hate being treated like a mushroom. So the only remaining question is why the DEF code was thrown at all. Granted it froze but they all must freeze in the north and not all have this problem. The tank was between 1/2 and 3/4. The temp change might be an issue causing a DEF sensor malfunction or a line problem, but that is pure assumption. It ran for days in below zero weather so the DEF heater must work or was not engaged due to the low temp. My remedy: learn to reset the code and if a recurring problem the big tune. I get at least one compliment on my truck at every stop, I just smile. It was so disheartening to stand next to this beast with a broken leg in the middle of nowhere as the gawkers passed by. A few stopped to ask but none could help. A good story that interests few. BTW can a DPF be full when the gauge reads empty?

 

[AH64ID]

The DPF shouldn’t be full with a gauge at zero, but you’ll still regen on the 24 hour schedule.

 

[mbarber84]

The DPF shouldn’t be full with a gauge at zero, but you’ll still regen on the 24 hour schedule.

Do you know the 24 hour cycle is for-sure a certainty? It would track with what my truck does (2022 3500 HO) but I had someone on another forum vehemently disagreeing with me, stating that the only way an active regen will trigger is when the soot load in the DPF reaches a pre-programmed threshold. That didn’t seem to track with what I see on my truck. Definitely thought it was on a time schedule (as well as the threshold).
I completely agree with you, RAM needs to give us better access to the information regarding what drives / triggers regeneration cycles, as well as other stuff like how idle hours are actually calculated. I barely idle my truck at all and I feel like my idle hour meter is way higher than what it should be. (Currently running about 27% idle compared to operating total hours).

 

[AH64ID]

Do you know the 24 hour cycle is for-sure a certainty? It would track with what my truck does (2022 3500 HO) but I had someone on another forum vehemently disagreeing with me, stating that the only way an active regen will trigger is when the soot load in the DPF reaches a pre-programmed threshold. That didn’t seem to track with what I see on my truck. Definitely thought it was on a time schedule (as well as the threshold).
I completely agree with you, RAM needs to give us better access to the information regarding what drives / triggers regeneration cycles, as well as other stuff like how idle hours are actually calculated. I barely idle my truck at all and I feel like my idle hour meter is way higher than what it should be. (Currently running about 27% idle compared to operating total hours).

Yes it’s a sure thing, and easy to track.

Idle hours seem to add up faster on my ‘22 than my ‘18, and both have been driven the same. I wonder if there is a slight threshold difference and done slow operation counts as idle on the ‘22.

I’m at 11.8% on the ‘22, which has been dropping. It was around 16%. I traded my ‘18 at 8.1%, and it was never over 9%.

 

[mbarber84]

One of the dealers said don’t shut it off until you get to where you are going. Not sure if that would have helped, advice came too late. Might as well have an electric vehicle when Ram dealers out here are a minimum of 100 miles apart and usually 200 miles. 5000 miles on the truck and ready to trade. Not sure a different brand would help, the sensors are probably all made at the same Chinese factory.

From what I see / hear / read, these DEF issues are frequent across all of the “big three”. I think a vast majority of the issues comes from either the temperature or the quality of the DEF. When the dealer scanned your truck, did they specify to you which code was triggering the “service DEF system” message? I just ran my 2022 3500 HO through some of the coldest weather we’ve seen here in southwestern PA in a long time. Ambient temp varied between 0° and -10°. I knew this was coming and prepared in advance. Made sure my DEF tank was no more full than 3/4 and put some fresh stuff in the tank just before the cold spell hit. The truck was plugged in at night, and run every day for a week in those temps. I was expecting an issue with DEF as others had mentioned in so many previous posts but I was relieved that I had zero issues.

It might be time to have a dedicated DEF system thread to start tracking this issues. Accumulating information and concentrated knowledge/ experience will help us all to better understand these issues and potentially hone in on any flaws.

 

[mbarber84]

Yes it’s a sure thing, and easy to track.

Idle hours seem to add up faster on my ‘22 than my ‘18, and both have been driven the same. I wonder if there is a slight threshold difference and done slow operation counts as idle on the ‘22.

I’m at 11.8% on the ‘22, which has been dropping. It was around 16%. I traded my ‘18 at 8.1%, and it was never over 9%.

Definitely.

My idle hours are WAY higher on the meter than what they should be in reality. My previous 2017 truck I sold had about 15-17% and none of my driving habits have changed between the two trucks. There has to be some change in the parameters they’re using to calculate what constitutes “idle”.

Generally speaking this 22 is quite a different animal over my previous 17. I just did an engine oil analysis on my second oil change and had 6.4% fuel dilution, which was startling. Never saw that kind of fuel dilution on my previous truck.

Also seems like this truck regenerates more frequently. I don’t know if that’s actual or if it’s just because I now have a gauge to look at.

In terms of the DEF, I had one related malfunction at around 6,000 miles on the odometer. Ended up being a faulty injector that the dealer replaced under warranty. I think a lot of the DEF issues that occur with these trucks early in their life have something to do with the 4-6 month time frame from build to delivery at the dealer. The fluid sitting in the tank for 4-6 months has to lose some of its quality. Especially in the heat of the Mexican desert when they’re stored there for months on end. You take into account some evaporation of the deionized water and you’re left with a higher urea concentration than normal. Mix in some fresh fluid at the time you take delivery and now you’re running the risk of the water / urea ratio being off. Also, I think the injectors tend to crust up faster when new for the same reasons above. Short runs and long sit times during the transport and delivery portion of their life.

Just theories at this point but worth noting / discussing.

 

[flan]

Every time a truck goes into limp mode because the DEF system froze a NHSTA report should be filed. It’s a safety concern and obviously the system is not working as designed. That’s how the CP4.2 investigation started and here we are getting a reliable fix.

Report a Safety Problem | NHTSA

File a complaint with NHTSA if you experienced a vehicle, tire, car seat or equipment safety problem that could be a safety defect.

www.nhtsa.gov

 

[mbarber84]

Every time a truck goes into limp mode because the DEF system froze a NHSTA report should be filed. It’s a safety concern and obviously the system is not working as designed. That’s how the CP4.2 investigation started and here we are getting a reliable fix.

Report a Safety Problem | NHTSA

File a complaint with NHTSA if you experienced a vehicle, tire, car seat or equipment safety problem that could be a safety defect.

www.nhtsa.gov

Agreed. The heaters should be sufficient to thaw the fluid completely. I think an electric element was a good idea since it works faster than waiting for engine coolant to warm up, however they don’t seem sufficiently powerful enough.

Question: do our trucks purge the DEF lines when the truck is shut down?

I have Deere tractors with DEF systems and those are programmed to run the DEF pump and push all of the fluid out of the lines and back to the tank every time the tractor is shut off.

 

[AH64ID]

Question: do our trucks purge the DEF lines when the truck is shut down?

I don't know if they purge, but I do know when I start my truck that the injector is commanded to 100% and there is no DEF line pressure so it should be able to drain any fluid back the tank... but that's just a guess.

 

[Surgdoc4]

From what I see / hear / read, these DEF issues are frequent across all of the “big three”. I think a vast majority of the issues comes from either the temperature or the quality of the DEF. When the dealer scanned your truck, did they specify to you which code was triggering the “service DEF system” message? I just ran my 2022 3500 HO through some of the coldest weather we’ve seen here in southwestern PA in a long time. Ambient temp varied between 0° and -10°. I knew this was coming and prepared in advance. Made sure my DEF tank was no more full than 3/4 and put some fresh stuff in the tank just before the cold spell hit. The truck was plugged in at night, and run every day for a week in those temps. I was expecting an issue with DEF as others had mentioned in so many previous posts but I was relieved that I had zero issues.

It might be time to have a dedicated DEF system thread to start tracking this issues. Accumulating information and concentrated knowledge/ experience will help us all to better understand these issues and potentially hone in on any flaws.

I did all of that to prevent this from occurring. Blue DEF, plugged in, etc. I even thought about putting a 12V battery blanket around the DEF tank and hooking to an aux switch but did not follow through. Not sure if it would help or hurt. The dealers I contacted all admit this is a common problem and get backed up for weeks because of it.

 

[the.tru.albertan]

My brothers truck hasn't come off FULL for the DEF since it froze in BC almost a month ago. (Saga was in the other DEF thread)

Abysmal system. Should never have been thought up. It's just a headache.

We have diesel air compressors at work. They run for a bit and then shutdown because the DEF freezes. So we hoarded them in and then they shutdown on high temperature. Lol, what a joke of a system.

 

[jebruns]

It really is crazy they built these systems around a fluid that freezes so easily.

 

[Surgdoc4]

What are the pros and cons of putting heating units around the DEF tanks and hooking into Aux switch for cold weather use?

 

[AH64ID]

My truck got very cold soaked this week. Temps dipped below 0°F on Sunday and didn't get above 12°F until this morning. The low temp Monday morning was -19°F, and -11°F yesterday. Today was a balmy 6°F, but got down to -10°F for a bit of the drive. I was driving twice a day on the cold days, but not far or long, so no real time to observe the DEF data.

I did notice thou the DEF temp stops at 12°F and the concentration goes to 0% when it's frozen. The temp fluctuated between 12° and 18°F, but the concentration stayed at 0%. It did open the injector to 100% a couple times, but no line pressure.

So on the drive home today I kept an eye on it. It took until the outside temp was above 12°F for any noticeable temp rise in the DEF, which makes me think it wasn't even trying to use the heater until is was above 12°F outside. I got above 12° after around 2 hours of driving. Once it got above 12°F outside the line pressure was low and the injection held 2-4% for a while, which makes me think the truck was trying to see if the line was thawed.

Does anyone know what the paramaters are for the DEF heater to operate?