HD2500 Cummins displays "Service DEF System" message intermittently

[HighDesertRam]

About two weeks ago, I received the message "Service DEF System - See dealer" on the dash intermittently, twice on one day and then several days later. I always use DEF from a very reliable high volume truck stop pump, so I believe it to be fresh. This occurred after my truck had been sitting with very little use following surgery. The first time it occurred was following a trip to the dealer for the electronic stability control software update. I never received the notice from the truck that it would be going into "limp" mode. On the three occasions where this happened the message disappeared quickly and has not happened again.

I took the truck to our local diesel specialist where I trust their knowledge and service. They threw an electronic analyzer on it (not the dedicated RAM analyzer) and saw nothing there that indicated there was a problem. I've gone another week with a couple of freeway runs and received no further error messages. However, I have a camping trip and a hunting trip coming up in September and October where I will be towing my 10,000 pound travel trailer up into the mountains (we live at 5500 feet and I will be towing to over 10,000 feet).

My OCD self has decided that I need to have the diesel shop throw the RAM specific analyzer on the truck just to ensure there is nothing further to be done.

I'd appreciate suggestions from anyone who may have experienced a similar issue or has better information than I do regarding this topic. Thank you.

 

[18CrewDually]

Get the actual codes when they scan it. It could be something as simple as a dirty DEF injector nozzle for example.

 

[Billet Bee]

How can you be so sure that truck stop def pump was reliable? The underground fuel tanks get water leakage and that same thing could of happened with the def, so I hope that was your experience since it went away fairly quickly. That's why I never personally buy def at the pump stored in a container underground, because my ocd about potential water penetration and the high expense to fix these things

 

[18CrewDually]

How can you be so sure that truck stop def pump was reliable? The underground fuel tanks get water leakage and that same thing could of happened with the def, so I hope that was your experience since it went away fairly quickly. That's why I never personally buy def at the pump stored in a container underground, because my ocd about potential water penetration and the high expense to fix these things

What he was saying was due to the high volume the DEF is sold at that location it has a high turn over rate so it more likely is fresher than a small low volume station.
Above ground tanks are less atmospheric stable since it's subjected to temperature swings resulting in wicking of moisture from the air when the fluid cools overnight. I'd rather pull from an underground tank, which have pits around the fill holes so unless the sealing cap is off during a flood it can't get contaminated.

 

[Billet Bee]

What he was saying was due to the high volume the DEF is sold at that location it has a high turn over rate so it more likely is fresher than a small low volume station.
Above ground tanks are less atmospheric stable since it's subjected to temperature swings resulting in wicking of moisture from the air when the fluid cools overnight. I'd rather pull from an underground tank, which have pits around the fill holes so unless the sealing cap is off during a flood it can't get contaminated.

Like you said, more then likely fresh, but there's no way to tell or a freshness seal or a date code. All I'm saying is poo poo happens and when my mom worked at a nationally own gas station there below ground tanks were leaking for years and taking in water and it was a known issue and nothing was done until much much later. So stuff happens and i prefer to get my def in a more controlled packaging system to keep out contaminants. Yes something could get into either scenario but in my opinion it's more likely in an underground tank situation, but thats just my ocd from seeing it happen from 2 company's I was familiar with and one of those was a commercial trucking company where they would literally throw away $20,000-$30,000 on each truck when the regen systems were failing left and right. So I had that nightmare to live with and fear which is why I'm overly cautious with our regen system, you just don't want to cut any corners what so ever when it comes to anything regen related because repair costs add up quick and never stop.

 

[Choupique]

You might ask that they drop the header from the def tank and clean it with warm distilled water, clean the injector with warm distilled water.

Something like this is usually an intermittent DEF level or quality sensor fault. It'd help to have the actual fault.

I've long stated that a standard 50k mile maintenance practice should be cleaning the def header and nozzle, and pumping some distilled water through everything. Unfortunately the latter will throw def quality faults, trigger XX miles to limp, and sometimes it's tough to make that go away. Removing and cleaning it is however generally harmless if they don't screw anything up doing it.

Filling the system with warm distilled water and pumping it all out through the injector would dramatically extend the service life of this stuff. Hot shot trucks don't really have problems with it because it stays pumping and gets consumed quickly.

 

[HighDesertRam]

How can you be so sure that truck stop def pump was reliable? The underground fuel tanks get water leakage and that same thing could of happened with the def, so I hope that was your experience since it went away fairly quickly. That's why I never personally buy def at the pump stored in a container underground, because my ocd about potential water penetration and the high expense to fix these things

You're right, I can't be 100% sure that this is the best source of DEF outside of a box with a date on it. However, this is one of the newest gas stations in town, a Mavericks, for those who live in Utah. It's less than 5 years old. Rust is not something we see much of here in Southern Utah, due to the very dry conditions we have here, so I would be very surprised if their tank was leaking.

Besides the big rigs that frequent that station (it's right next to the freeway) I might add we have a very high percentage of pick-up trucks here in this town. That station is probably frequented by many residents, too, and it's where I normally have bought my DEF since I purchased the truck in 2022.

 

[tjfdesmo]

Did the shop at leadt test the DEF with a refractometer or hydrometer?

Otherwise, I agree with flushing the DEF tank, then refill with fresh. Your initial post said the truck had been sitting is a definite red flag.

 

[crash68]

The underground fuel tanks get water leakage and that same thing could of happened with the def,

Unless the water goes down the port that used to fill the underground tank, it doesn't leak in from the ground.
All the underground tanks nowadays are in dual walled tanks with leak detection. It's a federal mandate as to stop contamination of the ground, it's been mandatory for over twenty years now.
Truck stops also need to ensure they're selling a good product as if the DEF or fuel is proven to have caused damage, they'll be on the hook to pay for the repairs.

 

[HighDesertRam]

Did the shop at leadt test the DEF with a refractometer or hydrometer?

Otherwise, I agree with flushing the DEF tank, then refill with fresh. Your initial post said the truck had been sitting is a definite red flag.

No, they did not test the DEF. I will ask them about that.

I had surgery in mid June and was not able to do any of my normal activities like hiking or working out, no lifting over 10 pounds, etc. I didn't do much driving during that period but it was only for about 6 weeks.

 

[Choupique]

flushing the DEF tank, then refill with fresh.

You can remove the fill line from the tank fairly easily and siphon it out from there. Be sure to use clean brand new tubing if you elect to do that.

Fresh def will dissolve deposits up to a point. The best thing is to use it. Some people dilute it to the lower limit of the acceptable range, which requires a good scanner and some work to do without triggering limp faults.

Unfortunately the only reliable way to do it is to remove everything (header, tank, injector) and clean it all, and flush the lines with distilled water, and reassembled and refill.

I'm patiently waiting for the day that these systems are designed conducive to flushing at regular intervals. It would solve nearly everyone's emissions systems problems, dramatically reduce the temptation to delete, and be all around far better for everyone.

 

[svanarts]

I've gotten the same DEF messages as the original poster. I live in California and since he lives in Utah I'm wondering if the same thing is causing the message for both of us. I reported the same thing to my dealer. Same answer, they couldn't find anything wrong. Then he asked me an off-the-wall question: Had I been driving at higher altitudes? In fact, I had. I had just driven over Carson Pass on Highway 88 in the Sierra Nevada. The message came on when I climbed through 7500 feet. He said he hear of it happening to another 3500 owner who had just come from Lake Tahoe.

So I'm wondering if the original poster was driving above 7500 feet or so?

 

[HighDesertRam]

I've gotten the same DEF messages as the original poster. I live in California and since he lives in Utah I'm wondering if the same thing is causing the message for both of us. I reported the same thing to my dealer. Same answer, they couldn't find anything wrong. Then he asked me an off-the-wall question: Had I been driving at higher altitudes? In fact, I had. I had just driven over Carson Pass on Highway 88 in the Sierra Nevada. The message came on when I climbed through 7500 feet. He said he hear of it happening to another 3500 owner who had just come from Lake Tahoe.

So I'm wondering if the original poster was driving above 7500 feet or so?

I live in the high desert at 5500 feet. This first occurred when I was in another town at an elevation of 2800 feet. The problem appears to have cured itself and I have been hunting the last couple of weeks and had the truck up at 8500-10,000 feet for multiple days with no issue. But thank you for that insight.

 

[WY-Dave]

Amazon lil toy for ~$20. I got one because i am a cheap basstard. There is a shop that heavily does diesel work and they have an fancy electronic tester and both read the same. Even water down a cup of DEF and still both read the same. I have bought big company DEF since the 2x needing to fill up, so that about 100K on Wally World brand. Some may say overkill, but I will know that what I put in is good. The tester is small enough to put in the glovebox and test at the pump

search DEF analyzer

 

[Lukeott]

I've gotten the same DEF messages as the original poster. I live in California and since he lives in Utah I'm wondering if the same thing is causing the message for both of us. I reported the same thing to my dealer. Same answer, they couldn't find anything wrong. Then he asked me an off-the-wall question: Had I been driving at higher altitudes? In fact, I had. I had just driven over Carson Pass on Highway 88 in the Sierra Nevada. The message came on when I climbed through 7500 feet. He said he hear of it happening to another 3500 owner who had just come from Lake Tahoe.

So I'm wondering if the original poster was driving above 7500 feet or so?

I to have gotten the check engine and def . The check engine light came on after the def warning showed up. I don’t think it’s has anything to do with the def that you put in the truck. My truck also has a warning that after 120 miles from now the truck will not be able to over 20 mph. So I have to take it to the dealer. One thing that I noticed with my 2018 diesel is it doesn’t do the regen . Seems strange because my 2013 diesel did the regen thing quite a bit. Did RAM change something that it doesn’t need to regen?

 

[LT37]

Had a similar situation. End of May the check engine light came on. 2018 Ram 2500 6.7. Had the recall completed about 87,000 miles. At the dealer it indicated a problem in the emissions system. Luckily, I was covered by the Cummins ext emissions warranty. Both NoX sensors, catalytic convertor and DEF injector replaced early June. All good. Maybe? Last week, 106,000 miles, about 3 or 4 minutes after cold start up Service DEF System alert popped up followed a short time later by the message icon. About 4 or 5 miles later it went away? Today, almost the exact same scenario. No codes being set. DEF tank was at half full on the first one and a little over a quarter full on the second one. I'm pretty sure the DEF injector is not a problem with only 20K miles on it. A little puzzling but then again it's a DEF system!!!!!!

 

[ppine]

Try a dose of DEF conditioner. It is mostly used to prevent freezing in winter, but might help you out.