DEF/SCR system failure , need some info

[-gtsm-]

Found this on the Ram Forum ... I wonder if draining some DEF will wake the sensor up?

"1st time on forum owner of a 2019 3500 draw limited After 100 miles my DEF see dealer light came on shortly after that can the notice you have 150 miles it shuts down to 5 mile an hour. took it to the dealer they said the def was overfilled and drained 2 gallons so now my gauge is between Full and 3/4. Is there such a thing as overfilling the def tank if so how do you not overfill it. I would have thought they would have filled it properly and see what would happen to determine if I have a bad sensor. Anyone with thoughts"

Watched the video posted earlier... Motor city mechanic video guy said sensor only reads when its exposed to air.

 

[Wiredawg]

I found the one I was looking for and this is the post:

"So for those of you who are interested I solved the problem. The truck def gauge showed empty with the add def you have 200 kilometres left warning. The check engine light was not on and there were no codes. Repeated starts made no difference to the problem. I got down to 100 kilometres left unlit 8 kph. This afternoon I took the metal plate of from under the def tank. Unplugged the wiring harness from the pump/level unit. Started the truck which generated a check engine light. Stopped the truck cleared the codes with a scanner (all ten!). Plugged the wire harness back in and low and behold the def gauge registered full. Problem solved. No idea why."

Anyhoo, that's all I could find.

Cheers, Ron

 

[-gtsm-]

Thanks , Ron . My friend is going to the house tomorrow and is going to dump half the fluid out and see if that wakes up the sensor. I tried clearing the codes and then disconnected batteries as you suggested earlier.
The TSB is Not applicable to 2017 vehicles . Even though it could be the same problem .

 

[Timd32]

This is a long thread about the DEF system.

I seem to.remember some parts address the toxic nature of DEF on the pumps and the sort. Might be of some help, others might be able to point to a certain area to start with in the thread.

https://www.turbodieselregister.com/threads/def-mixture-distalled-deionized-water-10-17.267404/

 

[Wiredawg]

This technique of disconnecting the DEF module, then starting the truck, setting codes, shut down, reconnect DEF module, restart truck, and then clear codes might work if draining some DEF out doesn't. I hope something works tomorrow.

Cheers, Ron

 

[Timd32]

I have a 96 so no DEF for me, but hope you get this worked out.

There are a few TSB on this topic, not sure if they apply.

Also another thread to read..

https://www.turbodieselregister.com/threads/service-def-see-dealer.266808/

When you search make sure the search thos forum only is NOT checked. It sometimes auto checks on my phone.

User TCDiesel has a lot of posts about this topic, so you could search DEF then add user TCDiesel.

 

[-gtsm-]

...Some interesting ******* matches in those threads

 

[Ozymandias]

Why not FIRST go to a Dealer, let them proper diagnose (thats more then just read a code!) the system with its wiTech, maybe install an upgraded software that maybe solves the problem.

Now we start with throwing parts at it...
Without any clue what's wrong aside from a Generic OBD code.

That is to put the cart before the horse.

 

[-gtsm-]

Well because this happened on memorial day weekend and I was hoping to understand the problem and possibly fix it(with help from a family friend) prior to her going in to the dealer this week . By the way we are already in line for a replacement head for our Jeep this coming week ... which is kinda leaving us short of vehicles at the moment . Trust me if draining half the fluid tomorrow doesn't work it's going to the dealer ... if software fixes it great ... but if it doesn't and they throw parts at it at dealer prices I'm gonna be hurtin'...we are cutting it thin on funds due to the current pandemic and it's effects on commerce ... my wife's a small business owner (Veterinarian) and I work offshore and had to jump through major hoops just to get on the job I'm on now .

 

[Ozymandias]

You can still take it out after the diagnosis - tell them you just want to know whats wrong and then decide how to proceed.

And if you want to keep it - get yourself AlfaOBD and do your own diagnostic.
You can not fix this new trucks without a computer.

And there are as many updates for the whole Electronics out there as for an Android Phone, these Trucks are in general said not finished from factory, they need the updates to correct things that went wrong from factory.
Especially for the DEF system, that is known to have bugs over the years.

 

[jetmechabq]

here is a used part if it helps

https://www.buyautoparts.com/buynow...&utm_term=4582695747879581&utm_content=[45-7]

 

[Wayne M.]

I’ve said it before and I’ll repeat. FCA MUST get a handle on their parts prices! The expense of these SCR parts is really insane. Dare I say class action lawsuit? I mean I can replace the pump, heater, line and injector on a Ford SD for under a grand (in parts expense). These things do go bad, they’re surely a planned obsolescence deal.

 

[TFucili]

Will Alfa OBD run the prime override for the DEF pump? I saw it mentioned in one of the things I read in digging around on this issue. Not sure if it is a mandatory step after replacing the pump/sender unit.

 

[Wayne M.]

Will Alfa OBD run the prime override for the DEF pump? I saw it mentioned in one of the things I read in digging around on this issue. Not sure if it is a mandatory step after replacing the pump/sender unit.

Can’t speak for the FCA deal but Ford gives you a syringe deal and instructions on priming the pump at install.

 

[-gtsm-]

Again thanks everyone for the input ... Jetmech that part is not correct for my truck but thanks anyway ... Ozy you seemed to have missed the part where I'm at sea ... and this is my wifes truck and I'm trying to fix the the thing by Email . I have an HPTuners MVPI2 and VCM suite at home but no one there knows how to use it but me .My friend dumped 2.5 gallons of fluid out this morning and the gauge still does not move... My wife tried to get the truck into the dealer and they won't see her until June 3rd they are that booked up ... she is trying to find another dealer to take it to.

 

[-gtsm-]

...Found alternate dealer ... she has appointment tomorrow .

 

[Wiredawg]

...Found alternate dealer ... she has appointment tomorrow .

Ask them for the old one... I would like to test it and dissect it for info... I dont mind paying shipping. Requesting your permission.

Cheers, Ron

 

[Wayne M.]

Good luck. Praying for the tech’s wisdom.

 

[CBari]

I have had mine do all kinds of weird stuff when I have run it low on the highway towing my LQ horse trailer. I don't like to add def till the light comes on that way I can add two full jugs. I usually get the 250miles to limp warning but on occasion I have pissed it off for lack of a better term. I will light up all kinds of lights and warnings and see dealer messages. I usually will fill the def up and after half dozen to dozen key cycles it corrects itself. I have about 100k on my truck and I bet it has done this 3-4 times.

 

[-gtsm-]

Copy that guys, I'll let you know how it goes . If they change any parts I will get the old ones . I usually do .. had rockers and cam changed under warranty on my Jeep recently and asked for parts out of curiosity and to go on my " offerings to the gods of speed " shelf . Was bummed when I got them in the bag that the replacement rockers came in and read "Made in China" . SMDH