DEF sensor simulator and other emissions stuff

[Rich W.]

So here’s the DSS:

DEF Sensor Simulator

Designed for Spartan (Shaw Development) DEF heads, but will work with Freightliner and now included at the website is the correct connector so that you can build one of these, soup to nuts, from sources found at the website. Be advised that with the simulator in place you can go merrily on your way (after code re-set) but will need to monitor your DEF level manually and keep your tank adequately full or you’ll create other issues which will lead to de-rate. This is not a system delete, or system by-pass device, it is a DEF sensor (level, temp, and quality) by-pass device. The system will continue to work as designed and will still require DEF. Nuf said on that?

Also be advised it WILL NOT work for pre 2016 Freightliner systems. My coach is a 2016 but the chassis was actually built in 2015 so it has pre-2016 emissions, including a physical float and no qual sensor on the DEF Header (Freightliner’s term - Spartan calls it a DEF head) and is not an electronic, digital, CANbus (whatever) type unit, so the DSS is not compatible. I bought the parts to build one before I figured this out and ended up selling them at a small loss just to get rid of them and because at the time the parts were back ordered and folks needed them.

So, thats the story on the DSS. As to all other things diesel emissions related, I do think it would be nice to have a diesel emissions forum, as I noted on Neal’s current thread about his DPF issue, and maybe this will inspire the beginnings of such a forum, but for now this post will have to remain in residence on the Cummins forum (or where ever it gets moved if there is a better location that didn't occur to me).

On another note I use OTR Performance ( OTR Diagnostics | Professional ) diagnostics which allows all kinds of emissions interactions, and I was a beta tester on the new system upgrade. Fun stuff!

I also just purchased the Diesel Laptops handheld unit ( Diesel Laptops Handheld Heavy-Duty Scan Tool with Regen ) which I will review once I have it. I reviewed a couple other code reading/scanning devices that provide live data on a phone or tablet in a previous thread.

So I hope someone finds this useful and if it starts a new Emissions Forum, all the better, because I see a lot of emissions questions and problems, scattered about on various forums, and Im sure I miss some. Likewise when I have my next emissions dilemma (note when, not if) it would be nice to have a specific location to discuss it.

All for now,
Cheers!

 

[J&JD]

I’m one of those sad folks that had a DEF head failure & total derate with 47k on my Freightliner chassis. 130 mile tow after an overnight beside the road was not fun. Wouldn’t wish it on anyone.

 

[FLSteve]

Be advised that with the simulator in place you can go merrily on your way (after code re-set) but will need to monitor your DEF level manually and keep your tank adequately full or you’ll create other issues which will lead to de-rate. This is not a system delete, or by-pass device, it is a DEF Head(er) by-pass device. The system will continue to work as designed and will still require DEF. Nuf said on that?

@Rich W. - thanks for posting this. I have already built a Spartan simulator and carry it with us. However, I am not sure how to actually use it if needed. If I am driving and start getting the DEF codes (understand there are three levels??), do I have to wait until the engine goes through all the codes and stops before I plug in the simulator or can I just stop as soon as the 1st code shows up and plug it in. Also how do I do a "code reset" on the side of the road?

In other words what are the steps to follow from ... "everything is running ok and then a code shows up to having it plugged in and everything's ok again"?

FLSteve

 

[Rich W.]

I spent Thanksgiving 2020 in the N. Las Vegas Velocity Truck Center parking lot waiting for Friday so they could get me back on the road. Then had to turn around and head home after just starting out on a Christmas trip that year. Both due to DEF issues. After that I decided I had to take charge of my emissions system or it would keep leaving me stranded. On my last trip this summer, I drove 7700 miles with no issues. Before that earlier this year a little over 5,000 with no problems. Amazing!

 

[Rich W.]

@Rich W. - thanks for posting this. I have already built a Spartan simulator and carry it with us. However, I am not sure how to actually use it if needed. If I am driving and start getting the DEF codes (understand there are three levels??), do I have to wait until the engine goes through all the codes and stops before I plug in the simulator or can I just stop as soon as the 1st code shows up and plug it in. Also how do I do a "code reset" on the side of the road?

In other words what are the steps to follow from ... "everything is running ok and then a code shows up to having it plugged in and everything's ok again"?

FLSteve

There’s actually five levels: MIL/Check eng/Low DEF warnings, three levels of de-rate ending in a 5mph restriction, and then Stop Engine. All of these have their own additional SPN codes, and you want to avoid all of them as much of it as possible.

I would plug the DSS in at the first sign of trouble (i.e, erroneous DEF related fault codes) to avoid derate. You initially just get the check engine/low DEF warning lights, but at that point are not in any level of derate, so thats the time to intervene.

As far as code re-setting, theoretically five or six ignitions cycles (start and stop engine) with no detected issues will casue the ECM to automatically clear the codes, and several folks reported this worked for them. I don’t like leaving something like this too chance so I reccomended carrying something that will clear the codes.

Note that nothing will clear the codes and keep them cleared if the problem is not resolved. So far there is no de-rate override available other than for emergency vehicles and thats another story entirely. But the DSS reports normal DEF conditions to the ECM so the codes should clear as stated above.

 

[FLSteve]

I would plug the DSS in at the first sign of trouble (i.e, erroneous DEF related fault codes) to avoid derate. You initially just get the check engine/low DEF warning lights, but at that point are not in any level of derate, so thats the time to intervene.

As far as code re-setting, theoretically five or six ignitions cycles with no detected issues will casue the ECM to automatically clear the codes, and several folks reported this worked for them. I don’t like leaving something like this too chance so I reccomended carrying something that will clear the codes.

Note that nothing will clear the codes and keep them cleared if the problem is not resolved. So far there is no de-rate override available other than for emergency vehicles and thats another story entirely.

But the DSS reports normal DEF conditions to the ECM so the codes should clear as stated above.

Thanks @Rich W. - this was exactly what I was looking for. Will print it out and carry with the simulator.

FLSteve

 

[JRS]

Rich...... you've been providing great information!!! But, I'm a bit confused.
1) Once the codes are reset, I need to keep the DSS plugged in right?
2) But than later you post that "Note that nothing will clear the codes and keep them cleared if the problem is not resolved". So while waiting for Freightliner service, if the codes reappear, do I unplug the DSS and start over re setting the codes?
Thanks again for the posts

 

[Rich W.]

Sorry about the confusion. I’ve never used the DSS (it is not compatible with pre-2016 equipment) but here’s my understanding:

1. Yes. Once you plug in the DSS, according to several reports, the codes clear with a maximum of six ignition cycles - usually less. So it appears that you don‘t even need an external device (code reader) to clear the codes. I would have one handy just in case. The codes will stay cleared as long as the DSS remains in use because the ECM believes the DSS information, and can no longer access what the DEF head is saying about things. BUT if you fail to keep DEF in the tank, sensors elsewhere will identify the deficiency and you’ll once again have the resultant codes and be on the way to derating.

2. True only if you don’t have the DSS. That statement was in reference to clearing emissions codes without addressing the problem. You can clear codes all you want, but if the problem still exists, they will return. Since DSS simulates a working DEF head, it simulates that the problem has been solved, the ECM thinks the repair has been made, and it goes back to happy contented state. Codes stay cleared (as long as there is DEF in the tank available for the rest of the system), and derate goes away and stays away. While waiting for service any codes that could otherwise be initiated by the sensors in the DEF head will not reappear because it is disconnected and sitting dormant, having been replaced by the DSS. In effect, the DSS is a repair and you could run that way for ever.

The only problem you are then faced with is manually monitoring your DEF level because your gauges will steadily read around 1/2 to 3/4 even if you run the tank dry. And if you do that, there are several more sensors down stream that will identify the absence of DEF and you’ll once again be facing a derate. I’m not certain on ISL DEF consumption in a 40,000lb coach, but I would guestimate it at a conservative 200/mpg to be on the safe side. Your MPG is probably more than that. Mine (ISB) is just over 300, and I’ve read that ISX coaches run at closer to 100 mpg. Keep the tank topped up and you shouldn’t have any issues.

For anyone with a pre-2016 DEF system (mine is a mid-2015 chassis) the problem of erroneous tank level readings often comes from a mechanical float in the DEF tank getting gunked up and not reading the tank level. (See the TSB at: https://static.nhtsa.gov/odi/tsbs/2013/MC-10142383-9999.pdf). So my solution is to always keep the float mechanism wet by keeping the tank full. When I see it drop to 3/4 (one green dot low on the dash readout) I start looking for a convenient opportunity to throw in a jug. Between this and paying attention to the condition of my DPF, in 7700 miles on my last trip I had no emissions problems or even warnings the entire time.

Thanks for pointing out the need for clarification. I like my little emissions blogs - they help me keep all this overly complex, over-engineered emissions stuff straight…

PS: By way of disclaimer, anyone who believes the DSS overrides, deletes, or otherwise renders the emissions system non-functional has not done their homework. It simply disables automated monitoring of the DEF tank. The driver must then manually monitor the DEF tank level. The DSS does not disable any other monitoring. The system still works as designed and if it runs out of DEF, the sensors in both the dosing system and the SCR will detect the deficiency, report it to the ECM, codes will appear on the dash, and the derate process will be initiated.