Current state of the DEF debacle (as I see it) on Freightliner and Spartan chassis

[Rich W.]

I wrote this for another thread and when I was done, thought it might be more useful and visible here rather than on the end of a thread many wont read . (Hope this isn’t a double posting violation). Enjoy!

The following list details what I view as the current situation:

• Freightliner DEF headers (I believe still supplied by TE connectivity) manufactured after 2021 seem to have very few, if any failures. It’s early though so time will tell.
• Spartan is still having problems as of 2022 although they are also using a new supplier - Errecinque. Whether they are still using Shaw or not I don’t know, but they still have problems.
• For either Spartan or Freightliner post 2016, the DSS will work and is cheap insurance. If I had one of these coaches I’b build the DSS and carry it at all times. The plug for the harness is chassis specific.
• I’m still seeing failures on pre-2016 rigs and for these the DSS will be of no help. For Freightliner rigs, a new (current gen) DEF header will likely solve the problem. For Spartan rigs I’m not so sure - depends on whether the new Errecinque heads are sound, and the status of Shaw supplied units.
• For any units under five years old and under 100,000 miles all emissions issues are covered under warranty and as stated above the DSS will get you through until repairs can be made.
• For those of us with pre-2016 rigs, we are on our own for repair costs, and there is no DSS type device to bail you out. Unless you already have a new DEF head installed (from a more recent failure), it would probably be a good idea to carry one and learn how to install it unless or until you have a current DEF head installed. This is not a popular option but it will keep you from being stranded.
• Many pre-2016 failures are due to residue on the mechanical tank level float. The DEF head can often be removed and cleaned and put back in service. Info on this can be found here: https://static.nhtsa.gov/odi/tsbs/2014/SB-10046782-4244.pdf . Keeping the tank as full as possible at all times (to keep the mechanical float apparatus wet) will help prevent this issue.
• Many post 2016 failures are due to faulty “Quality” sensors and all the sensors (all solid state) seem to have corrosion issues. Keeping good DEF in the tank (in spec and never over-heated) will go a long way to help avoid issues. A $25 refractometer will help make this determination.
• Coach-net is apparently working with Spartan to get folks back on the road more quickly providing mobile techs, and Spartan seems to have at least solved the supply chain issue and will ship the parts asap these days.
• There is a new software “patch” available from Cummins and sanctioned by the EPA that will by-pass a bad DEF head and Cummins will install it if parts are unavailable, but only after your DEF head fails, so unless it fails in their parking lot, it is a totally useless gesture.
• The DEF tank heater valves are still failing, although apparently infrequently, and that will kill a DEF head. The preemptive solution to this is to install an external valve in the DEF tank engine coolant supply line and keep it off unless you need it, or by-pass it all together. Since DEF doesn't start freezing until 12°F, most of use will never need a DEF tank heater.
• All the reports to the NHTSA on the issue seem to have fallen on deaf ears - there has been no response to anyone that I know of and it would appear they are completely ignoring the issue, most likely because it’s a government mandated problem.

This list ended up being a little longer than I anticipated, but it should help folks navigate the problem.

 

[Neal]

Seems to peak in summer peak heat season. Y'all come with me on my Banff and Jasper adventure and you don't have to worry about these things now do yaaaaah?

 

[sheridany]

Seems to peak in summer peak heat season. Y'all come with me on my Banff and Jasper adventure and you don't have to worry about these things now do yaaaaah?

The inventory of tiresocks would be seriously depleted.

 

[Joe Hogan]

Considering building a DSS for inventory of spares. Even if I never need it, it is an interesting project.

Reading the build directions, it appears a relatively straightforward DIY project. Practice up on fine soldering and should be a pleasant afternoon activity.

As always, what can go wrong?
Is there a way to test functionality prior to attaching to the DSDP DSP Head in some dimly lit space in the middle of the night as 18 wheelers fly by? OK mine as well and rain/downpour to the scenario!

Flashing lights on the Board good enough?

 

[Rich W.]

Considering building a DSS for inventory of spares. Even if I never need it, it is an interesting project.

Reading the build directions, it appears a relatively straightforward DIY project. Practice up on fine soldering and should be a pleasant afternoon activity.

As always, what can go wrong?
Is there a way to test functionality prior to attaching to the DSDP DSP Head in some dimly lit space in the middle of the night as 18 wheelers fly by? OK mine as well and rain/downpour to the scenario!

Flashing lights on the Board good enoug to test a DSS,

To test a DSS I would think you could simply wait until your DEF tank is below 1/2, install the DSS, and your DEF gauge should read 3/4. It would also be good to be familiar with the plugs prior to needing it.

 

[NWIP]

After building one I plugged in and ran the coach for approx 10 minutes with no ill effects. Hadn’t heard about 3/4 level as a check

 

[DennisT]

After building one I plugged in and ran the coach for approx 10 minutes with no ill effects. Hadn’t heard about 3/4 level as a check

One of the things the simulator does, from what I’ve read, is tell the system that def is 3/4 full regardless of the actual level.

So, if you hook it up when you are less than 3/4 the gauge should read 3/4.

Also means you need to keep an eye on actual level while it is installed.

 

[Rich W.]

One of the things the simulator does, from what I’ve read, is tell the system that def is 3/4 full regardless of the actual level.

So, if you hook it up when you are less than 3/4 the gauge should read 3/4.

Also means you need to keep an eye on actual level while it is installed.

Exactly because if you run out of DEF, even with the DSS causing the DEF head readings to be in order, one or more other sensors will detect it and start the derate process.