2017 2500 not using def

[Tommid]

Ok, I know this has been talked about but I can't find my situation. Here goes.. 2017Ram 2500, almost 50k miles. Everything was working properly before last service. Took approx 2500 mile trip last winter, burned 3/8 tank of def. Got service a couple months ago before going on a 2000 mile trip, and now almost 3k everyday miles and still no movement on def gauge. Tried topping off, took1 gal.. took to different dealership, did park regen (102 minutes), filter at 95%, Says everything looks good. Truck has never went this long on so little def. Any ideas?

 

[sag2]

Did the dealer run the DEF injector test? That would tell you if the system is capable of flowing an adequate amount of DEF. If not codes the truck thinks everything is OK. Wait for a CEL at this point.
BTW, the manual regen has nothing to do with the DEF system.

 

[Tommid]

I don't think they did that. Thank you very much, I will run it back up there.

 

[Wayne M.]

I’d run it to a fault. The SCR system is monitored so tightly, you’ll know pretty quickly if something is out of control.
Any after treatment system I’ve seen uses DEF during any regeneration. I’ve actually seen nox issues resolve themselves during a parked regen, usually after a repair.

 

[HPSimpson]

Sure wish I had your problem my '19 drinks like water about 1500 miles 3/4 of the tank is gone, had Ram dealer check "said that's normal"

 

[Tommid]

I’d run it to a fault. The SCR system is monitored so tightly, you’ll know pretty quickly if something is out of control.
Any after treatment system I’ve seen uses DEF during any regeneration. I’ve actually seen nox issues resolve themselves during a parked regen, usually after a repair.

I just talked to local dealer "Master diesel mechanic" he basically said same thing. Set my mind at ease on one hand, but still nervous that when something goes wrong, it's gonna be bad. Thanks for the help.

 

[Tommid]

Sure wish I had your problem my '19 drinks like water about 1500 miles 3/4 of the tank is gone, had Ram dealer check "said that's normal"

Geez, they have you coming and going!

 

[Wayne M.]

I’m self trained, only Mack Truck factory trained, but if you understand modern gasoline engine closed loop fuel metering, using the O2 sensors as feedback, then you can understand the SCR system. It uses the NOx sensors as feedback and DEF dosing as part as the strategy.

 

[gtwitch]

My 16 year change 17 (bought Feb 17) 2500 is very light on DEF when not towing probably 1/2 tank by the gage at 1000 miles and at just below 1/2 on gage I usually put 2.5 gal Blu Def from WalMart and that fills it by the gage, But put the 10-12K toy hauler on it for the winter and DEF consumption will double and obviously fuel consumption goes from about 19.5 mpg to 13 or less mpg towing. We live at 7300 ft and play most of the year above 10,000 ft.

 

[FrankG]

16, 2500 Laramie 68RFE, I think I can go 5 or 6K empty miles before DEF needle moves off full, hook to a trailer and it all changes. I figure about 2.5 gal of DEF per 10K (80% empty) miles.

 

[R.Taylor]

My 19 chugs it down.... I gather I've used no less than 12 gallons of DEF in the 8400 miles I've put on it since Nov 24th. Lead foot here always turning about 1900/2000rpm @ 82+mph unloaded. I've yet to have any of the recalls done, Curious about the "DJ D2 Diesel Engine Calibration" and what parameters it adjusts. Not much word here yet at least. Trucks running like a top, Still happy here.

 

[John Jensen]

DEF is only used during a passive regeneration.

Many trucks will never see a passive regeneration because they are not running hot enough. When towing, carrying a heavy load, or driving hard the EGT’s can reach passive temps of 700+f and then perform a passive regeneration and use the DEF. There will be no indication of the passive regeneration.

There is a recall that reduces the excessive DEF consumption in the 2019s.

 

[Tommid]

16, 2500 Laramie 68RFE, I think I can go 5 or 6K empty miles before DEF needle moves off full, hook to a trailer and it all changes. I figure about 2.5 gal of DEF per 10K (80% empty) miles.

Good to know, thanks

 

[sag2]

DEF is only used during a passive regeneration.

Many trucks will never see a passive regeneration because they are not running hot enough. When towing, carrying a heavy load, or driving hard the EGT’s can reach passive temps of 700+f and then perform a passive regeneration and use the DEF. There will be no indication of the passive regeneration.

There is a recall that reduces the excessive DEF consumption in the 2019s.

Ok, there seems to be a little confusion on DEF and DPF. First, DPF regeneration has nothing at all to do with DEF. Yes, you still use DEF during a regen, more than when not in regen (passive or manual) because of the higher exhaust temps=higher NOx levels. DEF is for NOx reduction only, nothing else. We had regeneration of the DPF long before we started using DEF.

 

[John Jensen]

What's the confusion? An active regen, the one that cleans the DPF, does not use DEF. DEF is only used by the passive regen.

 

[sag2]

There was a pretty good article in The Rest of the Story in Issue 102. You might take a quick look at it, he seems to have a good basic knowledge of the DEF system. I understand there is going to be another DEF article in Issue 109.

 

[MtnRider]

What's the confusion? An active regen, the one that cleans the DPF, does not use DEF. DEF is only used by the passive regen.

DEF isn't part of the regen process either way. DEF is sprayed into the SCR to reduce the NOx emissions, has nothing to do with the DPF or regens, completly separate functions. Regen is the process of burning off the soot captured in the filter, DEF is part of reducing NOx emissions.

With that said you will use more DEF during heavy towing or regen (anytime the combustion temp goes up) as that is when more NOx is produced.

.

 

[kthaxton]

What's the confusion? An active regen, the one that cleans the DPF, does not use DEF. DEF is only used by the passive regen.

As said, DEF is not directly related to regen. DEF is ALWAYS being dosed. And you're terminology is wrong.

And active regen, is when the PCM is calling for fuel to be added on the exhaust stroke to raise the exhaust temp to "clean" out the DPF. This is "active" because, well, it is an active process, a process that is specifically called upon to achieve a particular outcome.

A passive regen, is when nothing special is happening with the PCM/fueling. A passive regen occurs when the engine is being worked hard enough (towing, going up a grade) that the exhaust temps are naturally hot enough to clean out the DPF.

 

[Wayne M.]

I am not a WIITECH guru at all, but the 3 other OEM diesel diagnostic platforms I use will not allow you to view PIDs such as reductant pressure or injector duty cycle WHILE in a commanded DPF regeneration.
Does AlfaOBD Or WIITECH allow you to set off a regen, and leave that screen to look at PIDs? That’s what needs to be done, OR remove the DEF injector for a commanded regen and physically look for a spray.

 

[John Jensen]

DEF is sprayed into the SCR to reduce the NOx emissions.

And that is called a passive regeneration