Shaw DEF Head Failures - Summary & Potential Workarounds

[LWBAZ]

In this post…

https://www.irv2.com/forums/f278/def...ml#post5800678

…I included an electronic copy of a document originally written on 6/21/2021, summarizing the current situation surrounding Shaw Development DEF Head failures and listing a couple of potential short-term solutions.

Several of you were kind enough to offer suggestions for improvement, which I have incorporated into an updated version dated 6/24/2021. An electronic copy of that version is attached below. Once again, I will appreciate any comments, corrections and suggestions for improvement.

I’m going to ask the forum moderators to delete the PDF copy of the prior version from the post linked above and include a note directing interested members to this thread.

[Butte64]

Looks great, thanks. It would be great if RVIA, FMCA, and others affected by this issue would support this.

[tom chelbana]

As from the beginning of this DEF head problem you have done the best to share information that has been out on this serious problem. Your letter is right on target and makes a lot of sense and hope it bring some quick action. We need a high ranking government official who is a diesel RV owner to move this quickly forward.

[LWBAZ]

Thanks Tom. A friend & fellow Entegra owner has some plans for that write-up, but I'll let him speak for himself if he so desires.

[Archer2]

Thanks for the time you put into boiling all this down in an understandable fashion. Just for your reading enjoyment I found this Cummins AEB (Application Engineering Bulletin) #15.142 from 2014. It describes to the OEM Body Builders like Spartan/Entegra how to integrate all the OEM stuff into the Cummins ECU. START ON PAGE 44 for the DEF system.
One very interesting part solves the mystery of how long until the 5MPH “derate”…sorry, I should say “Inducement” LOL, goes into effect.
It appears that once the derate is triggered or “primed” by either fluid level=0 and/or fluid quality out of range it does a partial derate of 25% ramping up to 40% at 1% per minute and then it lies in wait until A) the ignition key is turned off OR B) the vehicle has had 0 ground speed (idling) for 1 hour OR C) it detects a refueling of an increase of 15%+ of fuel tank capacity. Once any of those 3 events transpire then you get the full Monty of a 5MPH speed limit PLUS a 40% torque derate PLUS a max 1000-1100RPM engine speed.
Here’s the link-it’s dense but interesting.

http://www.commercialtrucksofflorida...ders-guide.pdf

[Archer2]

I spoke to a low-level person at FMCA 2 days ago who promised to push it up to their legislative affairs department but I haven’t gotten any further info. I also sent email to 4 executives at RVIA. I haven’t gotten so much as an acknowledgment in reply from any of them.
In regards to a high-level political player who is an RV’er, there's Supreme Court Justice Clarence Thomas and his wife are long time Class A RV enthusiasts.

[Jlinnx01]

Apparently nobody at Newmar, Spartan, Freightliner,Shaw,NTSB, or anybody else involved in DEF systems really gives a crap about this issue. My wife and I and her brother owned a Chevy dealership for over 40 years and when EPA up with this DEF system we said it would become a nightmare somewhere down the road and here we are. The engine derate was a terrible and dangerous idea. Can’t believe the shortage of parts, how do these situations happen with alarming frequency? Even without a parts shortage, I understand the so called gen 7 head is failing as well. Has to be a temporary work around somewhere. I am so frustrated to have a 35000 pound, $4000,000 brick in my rv garage. Sorry but I needed to vent.

[Archer2]

After taking several Ibuprofen for the headache I got from reading a few hundred pages of Cummins and other documentation I believe that the following is possible. If one can source ANY DEF TANK and header that works with the Cummins ECU (CM2350).. so Freightliner, Winnebago, Newell, whatever. You should be able to just fabricate a cable with the correct male/female connectors and unplug the 4-pin connector on the bad Shaw unit and use the jumper cable to connect to the other Brand X good DEF header to the CANBUS. Leave the coolant lines and the DEF Fluid lines connected to the Shaw unit just as they are. Fill the “dummy”tank with a reasonable amount of DEF fluid and it should start generating “all-good” J1939 data frames with in-range parameters. The bad Tank should continue to pump fluid. The heater may not work depending on how it is controlled but that shouldn’t matter as long as it’s above 11 degrees F. As long as the correct J1939 valid messages are being sent to the ECU it doesn’t know that the data is coming from a different tank than the one that is actually supplying the fluid. The “dummy” tank could be located in a basement compartment as long as the homemade jumper is long enough to reach. The beauty of the CANBUS/J1939 standard is that the actual DEF tank and Sensors can be treated as a “black box” that just generates predefined messages. You would still of course have to manually keep the real tank replenished because it will continue to supply DEF to be consumed in the SCR system while the gauges will be really reading whatever the “dummy” tank level is. I haven’t considered where and for how much the Brand X tank/sensors could be sourced yet. I think this Rube Goldberg setup would work but I have no way of testing it right now.

[Gasman 2]

Archer2,
Thanks for thinking and working this through.
My understanding of the system it also monitors usage or tank level, if the ECU does not see the level changing it will think there is a problem. So if the ECU is connect to the dummy tank it will not see any change or usage of DEP.
Just my thoughts,

Richard

[brobox]

Originally Posted by Gasman 2

Archer2,
Thanks for thinking and working this through.
My understanding of the system it also monitors usage or tank level, if the ECU does not see the level changing it will think there is a problem. So if the ECU is connect to the dummy tank it will not see any change or usage of DEP.
Just my thoughts,

Richard

Yes, thank you Archer for putting ideas together.
One other issue of the dummy tank would be the problem I had. The fluid not being used would get old and trigger off the DEF sensor. The DEF fluid would have to be changed before trips.

[greeneville1]

Thank You Larry for putting into a precise condensed intelligent summary of all our frustrations and the dangerous effects of de-rating a large 30,000 to 60,000 lb RV with tow vehicle filled with good folks, children or grandkids and loving pets on interstate highways. Hopefully ,we can all get this message to our representatives who might care or to representatives who believe that helping the Rv Industry might gain them some votes in the next election. We all know by now that is how it works with government. Stay Safe.

[gswindle]

Nice write up! Thanks Larry!

Gary S.

[Gary.Jones]

Archer

Thanks for finding the information and then reading through all or most of it to come up with some understanding. Now, I have no political problem with there being a DEF quality sensor and government regulation of the amount of nasty black smoke coming out of our exhausts (do you older guys remember what a semi with 400,000 miles on the engine looked like as it was accelerating from a traffic light?????) (Huge clouds of black soot and exhaust). But there should be a work around.

The only real work around I have already mentioned before and that is for Spartan to get whoever does now make a DEF head sensor system that works to start adapting their system to Spartan's needs or that same company to simply make a compatible head assembly and then publish the availability of a free replacement with the good functioning DEF head for all coaches manufactured from around the date of failures becoming known to the current and all future Spartan chassis.

Won't be fun for Spartan's bottom line, but it is the right thing to do.

Gary

[brobox]

Originally Posted by Gary.Jones

Won't be fun for Spartan's bottom line, but it is the right thing to do.

Gary

I still remember the radiators....don't think that is going to happen UNLESS there is a government ruling on the defective DEF heads. Spartan has proven in the past they will not support their customers. It would be great if I was wrong.