DEF Head 3X unlucky

[NW-Dstar]

Well I've had my 3rd DEF head failure in almost 4 years. I had been towed 2x for this issue, but fortunately this time around I knew the protocol and didn't turn off the rig and made it home at 50% derate. I was at Yellow (Check Engine) status when I left home (risky I know) but made the 400mi R/T even though it escalated the error to Red (Stop Engine) by the return home. I had all the DSS parts arrive while I was gone and had extra DEF Head (freightliner) so no issues with the needed plug/wiring I simply snipped it off the old head. 10 minutes to build and program and Voila, 2 DEF errors cleared on first restart the remaining check engine cleared on 3rd restart. The most recent quickbuild cost less than $30 parts and shipping and well worth it. Now I need to schedule some time with Freightliner to get my 4th head replacement prior to my warranty expiring. Very nice to know what to do and how to self resolve and avoid yet another tow.

 

[Rich W.]

What year and model coach? Must be a 43’ Dutch Star around 2017 - 2018…? Unfortunate that you have to be this involved in your emissions system but excellent that you have educated and equipped yourself for it. I managed to get my emissions system under control just as my emissions warranty was coming to a close too.

How did you build a DSS fir $30? Care to post sources and prices of parts? Also are you using any form of diagnostics and code clearing or relying on your LBCU?

Sounds like you are well informed about the protocols of operating the vehicle when these problems arise - limiting ignition cycles, fueling, ect.

Do you have a list of do’s and don’ts? I’ve had trouble finding that info and its been a while since I read it. Thanks form posting this!

 

[mbutts4901]

I'm not a Newmar owner yet, but I have to say that this is one of the issues (besides Flexsteel furniture peeling and windows falling out) that are causing me to worry. Any idea on why they are continuing to fail?

 

[NW-Dstar]

What year and model coach? Must be a 43’ Dutch Star around 2017 - 2018…? Unfortunate that you have to be this involved in your emissions system but excellent that you have educated and equipped yourself for it. I managed to get my emissions system under control just as my emissions warranty was coming to a close too.

How did you build a DSS fir $30? Care to post sources and prices of parts? Also are you using any form of diagnostics and code clearing or relying on your LBCU?

Sounds like you are well informed about the protocols of operating the vehicle when these problems arise - limiting ignition cycles, fueling, ect.

Do you have a list of do’s and don’ts? I’ve had trouble finding that info and its been a while since I read it. Thanks form posting this!

2019 4018 DS instruction here: DEF Sensor Simulator – Quick Build – DEF Sensor Simulator i built the cheapest CanBed RP2040 nothing was needed to clear codes other than a few restarts after plugging in the simulator.

 

[Rich W.]

I'm not a Newmar owner yet, but I have to say that this is one of the issues (besides Flexsteel furniture peeling and windows falling out) that are causing me to worry. Any idea on why they are continuing to fail?

Freightliner seems to have solved the problem for the most part at this point (I believe thier DEF header supplier is or has been TE connectivity) and Spartan claims to have this under control (Shaw Development DEF heads) although they are on Gen 7 (or maybe Gen 8 by now?). But the jury is still out on that. Tiffin also had the problem with their Powerglide chassis coaches, as did any manufacturer using Spartan or Frieghtliner over the last 10 years. Its not a Newmar problem, its a poorly conceived, fragile, excessive, emissions control system requirements problem.

As to why they fail, it seems to have been difficulty developing materials handling and sensing devices that monitor and deliver corrosive materials (basically ammonia) in a mobile environment. The technology is at least 50 years old and has worked well in power plants, processing, and manufacturing. The science is good, but the implementation has been a disaster. Adapting it to over the road vehicles has been taken over 10 years, as has storage of DEF in a less than ideal environment. It was forced on us long before it was ready. It seems that at this point the worst is over, but there will still be failures and stranded motorists as the technology continues to improve.

The window issue seems to have started after Lippert bought out Hehr - something completely out of Newmar’s control. Not sure about the furniture issue, but I keep my coach climate controlled to prevent baking the interior during summer months. I don’t know if it helps, but I haven’t had any upholstery issues in my 2016.

 

[Neemer]

Holy carp! Three DEF header failures on a 2019 Freightliner? That’s very unusual.