DEF Sensor Simulator – Quick Build

Page last updated May 30, 2022

Since the original DSS solution published in September of 2021, the team has been busy looking at alternative hardware and software options. This page has a brief description and links to the build instructions for all the variants developed to date. The solution in the Recommended section has been deemed by the team to be the most viable current option considering factors such as price, size, parts availability, ease of programming, etc. Having said that, any of the build options are still viable solutions and provide options during times of supply chain shortages.

Currently Recommended DEF Sensor Simulator Build Option:

  • CanBed RP2040 – This solution has a Raspberry Pi processor as well as the CAN interface integrated on a single board. It is much smaller and at about $16 (for the board) very affordable. Stock is available from multiple sources. Programming the board is extremely easy and can be done from Windows or MacOS (MacOS instructions coming soon). However, it does require minor soldering of a 4 pin connector to the board.

Alternative DEF Sensor Simulator Build Options:

  • CanBed ATmega 32U4 – Board size (very small) is similar to the CanBed RP2040, it just uses a different processor (ATmega 32U4). At about $25 (for the board) it is a bit more expensive than the RP2040 but is also available from multiple sources. Programming the board is easy, but slightly more complex than the RP2040 and requires a Windows system. It also requires minor soldering of a 4 pin connector to the board.
  • Arduino DUE w/CAN Interface (Original Build) – This is the original project using an Arduino DUE board with separate CAN board add-on. It is currently  the most expensive alternative starting at about $135 and could cost as much as $190 depending how it is ordered. The CAN card has limited sourcing and is often out of stock. Programming the board is not difficult, but somewhat more complex than the RP2040 and requires a Windows system. It does NOT require any soldering.
  • Arduino UNO w/CAN Interface –  This build is similar to the DUE in terms of size and that it utilizes a separate CAN board. While not difficult by any means, it is probably the most involved in terms of assembly. Total cost will be in the $100 range. Programming the board requires Windows and is not difficult, but is somewhat more complex than most of the other options. It does NOT require any soldering.

234 Comments to DEF Sensor Simulator – Quick Build

  1. PETER G RIBBENS says:


  2. Duane Gordon says:

    Thanks to all who contributed to this solution. I was stranded in Tennessee for four days and a cost of $2000 plus dollars two years ago for this same problem.

  3. Jay Witthuhn says:

    Thanks to all that developed this! Question: Which chassis (Freightliner, Spartan, other?) has this been tested on?

    • Jwp says:

      Spartan chassis basically with the Shaw def head, 450 and 605 Cummins. We have also tested on an Int 4300 and Tiffin Powerglide.

  4. JOSEPH ZINKEL says:

    I have been following this issue and see a temp. fix has been put together.
    Thanks for all your work on this
    When trying get the parts to assemble this, I have run into a back order on the Arduino due from Copper Hills. They are not expected back in stock til end of October. We will be on the road and not able to receive. Due you know of any other sources?

    Also, Cable gland is also out of stock

  5. Wold says:

    Thank you for taking on this project and especially for providing the results of your efforts it in this mannner. The computer age left most of us hobby mechanics incapable of dealing with being stranded by faulty sensors. I’ve been there three times with no help form those responsible for this problem. You’ve gone above and beyond and done the right thing when others wouldn’t.

  6. David Telenko says:

    Greetings, thanks for putting the DEF fix together, seems easy enough to do, well if you have a PC. I myself have a Mac & I have several friends that only use smart phones!. So how are we supposed to do the necessary programing? My biggest concern is showing its ugly head already “PARTS”! Only makes sense that the parts are going to be hard to impossible to get. Thats why the auto manufactures & all others using chips or other electrical components are shutting down their plants! I’m hoping that maybe, just maybe that the necessary parts are made here in the USA & will be available!
    I’m not trying to be negative, just a realist to whats going on in our world.
    Thank you
    Dave Telenko

    • JWP says:

      Dave, We will be posting the instructions for a MAC very soon, as for the smart phone users, find a friend with a tablet or a laptop.

    • JWP says:

      Dave, Thanks for your concern. We have posted the alternative board and provided several other build options on the site. The parts are available sourced from US vendors. We will be posting the MAC instructions for programing shortly. As far as the smart phone users go, this would be a great time for them to make a friend with a person who has a laptop, tablet or Desktop computer with a USB port. This project is a DIY, not a one stop product purchase.

  7. Daniel G. says:

    Dave, I have a 2016 Dodge Ram 2500 6.7 Cummins Diesel, that pulls a 36 foot fifth wheel. Does all this information also apply to my truck. Thank you ahead of time.

    • JWP says:

      Daniel, The answer your your question is both yes and no. This project and the specific programing does not apply to your truck. The concept of DEF and the failures along with basic Def system design does apply to your truck. This Simulator will not work on your truck.

  8. Ed Puglise says:

    I’ve been running into DEF issues with my 2015 Duramax. After many visits to the dealership, one derate notice, and finally replacing a nox sensor, it seems like I’m back on the road. (With a lighter wallet).
    Couple questions:
    You’re mentioning Cummings engines but nothing about Duramax or other truck diesels. Do your fixes work for them?
    Any talk if manufacturers are going to extend their warranty?

    • Voltdoc says:

      Sorry this won’t work for your vehicle, the DEF simulator solves only a very specific set of faults generated by a failed DEF head sensor (most commonly made by Shaw). It does not address issues related to the NOx sensor. It has not been tested on the med duty engines and probably wont even hook up to them in this configuration. The connector and ECM programming may be OBD instead of J1939 and the DEF system is very likely to be different as well.

  9. Glen Allen says:

    Looks like a great solution Thanks for doing this. As you know the primary part is out of stock. You made a point of saying to select the extended power option on it. The alternative board you listed does not have an extended power option and I can’t find the input voltages in the specs. Is it OK to just order the alternative as listed? Thank You

    • JWP says:

      Yes the alternative part will work fine for this project.

      • John C. says:

        Another question came up for me while looking at the alternative board. That board does not have the same jumper pin location. Is there a particular setting on the alternative board. It looks like a more sophisticated board and a little more expensive. Also can the alternative board accommodate an LCD display. You example was off the first Board.

  10. Charles von Beck says:

    AsI tow with a 2019 RAM 2500 Diesel do they have the same issue? Might build one for emergencies.

    • JWP says:

      Charles, Although you have a Cummins Engine and the Doge Rams have also had DEF issues, this solution in its current form will not work for you. The coding for the ECM is different.

  11. John C. says:

    Another question came up for me while looking at the alternative board. That board does not have the same jumper pin location. Is there a particular setting on the alternative board. It looks like a more sophisticated board.

  12. Tom says:

    Wow. I appreciate you guys doing this. I ordered the parts before checking compatibility. I see the parts are flying off the shelves. Cable is back ordered, but I’m not in a rush. I am pretty sure my coach has the potential for sensor failure (Tiffin with ISB6.7 on Powerglide). It hasn’t happened yet, but I expect it will at some point, so I want to be prepared. I copied the content of your instructions to a Word file. Crazy world we are living in. Hoping the government doesn’t come in and shut your site down. Never ever would have expected it until 2020/2021 rolled around. Yes, I’m a bit paranoid these days. Thanks for your help!

    • JWP says:

      Thanks Tom, you can also order just the connecter with pig tail and use 16ga wire to build your own cable making sure to use waterproof connection as well.

  13. Val says:

    Hi, is it works with Cummins X15 engine ?

  14. William Whitenton says:

    Wondering if my coach is effected. It is a 2010 tiffin allegro bus on the powerglide chassis. The whole def contraption was replaced back in 2019.
    Also, i could not get the software to download. I got a message that the software could harm my computer.

    • JWP says:

      Yes your coach has the earlier version of def implementation on it. We have seen very few failure in comparison to the newer coaches due to the type of sensors used. On the software download, when the warning pops up depending on the OS version you should have the option to show details when click on the detail the option to keep or to download anyway will appear. Click keep or download.

  15. Michael Schwarz says:

    The alternative item #2 (Dual CAN Bus Interface For Arduino Due With Extended Power Range) is also out of stock. Are there any alternatives that will work?

    • JWP says:

      Michael, Yes there is, on the Right hand side of the page if you click Build It, scroll down to the bottom and you will see the build for the UNO and Mega.

      • Michael Schwarz says:

        Sorry to be a pest. I can’t find the term ‘build it’ anywhere on the Copperhill Technologies web page. Not sure what UNO and Mega means. I tried a search for them together and didn’t get any results. Can I get a few more details?

  16. Michael Schwarz says:

    The DT 4 pin wire is also out of stock at 1 meter, but the 3 meter version is available. Other than extra wire, is that a problem?

  17. Ken Colby says:

    Just wanted to say how grateful we are to all that have contributed to this issue as well as everyone that has submitted a complaint to NTHSA, EPA, Cummins,Spartan, Freightliner etc. I have ordered all the items suggested and just awaiting arrival now to start my build as there is no telling when Cummins will release some type of programming update.

  18. Stu says:

    I received the last of my parts this afternoon and in about half an hour I had the project completed. I’ve used Voltdoc’s instructions before for a different project and very much appreciate his concise, thorough instructions.

    Since my DEF head was working when I last shutdown the ISL 450 in my 2018 Spartan K2 chassis, I’ll hold the simulator as an insurance policy against possible future failure.

    I’m so grateful for the efforts of an enterprising group of individuals who put this insurance policy together!

  19. Kelly Fitzpatrick says:

    I see that all the options are backordered for the Arduino canbus adapter. I have a spare Raspberry Pi 3 and canbus adapter I used to interface to my 2019 Phaeton Spyder system, until I upgraded to a beefier RPi4 version. How complicated would it be to port to Raspberry Pi? Could you provide the low-level canbus timing settings and command sequences if I wanted to take this approach? Or is that info already available in your download package? Thanks!

    • Voltdoc says:

      Not right now, only the Arduino hardware specified is currently supported. There are no immediate plans to port to the RPi, however we may pursue that option when time permits. The CAN bit rate of the emissions CAN is the same as your Firefly/Spyder CAN, 250K.

  20. Daniel says:

    is there a way to get this to work with a raspberry pi?
    since all options are on back order?

    • Voltdoc says:

      Not right now, only the Arduino hardware specified is currently supported. There are no immediate plans to port to the RPi, however we may pursue that option when time permits.

  21. Roland says:

    I have purchased all the parts, but now the software will not run on my Windows 10 PC. Says “This app can’t run on your PC” To find the version for your PC, check with software publisher.

    I have tried different compatibility modes or running as Admin. Still no luck.

    • JWP says:

      Hi Roland, I will be glad to help you trouble shoot and get the software working for you. I have a couple of different ways that I can help. Lets start by direct email. Please check your in box for a email from me>

  22. JB says:

    If I get the correct connector, would this work on a Paccar PX9?

    • Sschevygrl says:

      Not sure about PX9, but we just installed Uno on PX7 in 2017 Kenworth T270 rollback and it appears to be working. DEF gauge went from “0” w/red light to 3/4 and after 3x of 5 min idle and restart all dash MILs are out. We did have a bit of extra figuring out on the plug because ours was a 4 pin spade, different color wires and different pin order, but once you find hot and ground, it’s a 50/50 chance on CAN L and CAN H. We had them backwards at first and the truck DEF gauge read “0”, as soon as we swapped the 2 wires, it worked like a champ!

      • Archer2 says:

        That is brand new, I think you are the very first PACCAR PX installation. If you have pictures of the actual connector as well as what color wires went where, if you could attach them or send them in an email to you might help others with KW PX engines.

  23. Walt says:

    The recommended supplier is out of stock on Dual CAN Bus Interface For Arduino Due With Extended Power Range. Is there other suppliers for this item?

  24. Francis McGuinness says:

    We full time in a 5h wheel/F350 diesel combination. Thankfully, we haven’t had this particular issue to deal with.
    That said, I am so impressed with the effort and cooperation that has gone into this project. My faith in the human spirit and American ingenuity has been verified (yet again).
    Safe travels everyone.
    We’re looking forward to seeing all you folks on the road again.
    Mack & Mary Ellen
    Somewhere, USA

  25. Marty Weston says:

    I just finished testing my DSS and it was a raging success! Thank you to all of those involved, I can’t convey how much all of your efforts are appreciated. As being the victim of a failed Def sensor while on the freeway enroute to a week long RV rally, I felt the frustration of being “out of control” to handle the situation. Not knowing if and when the rig would got to limp mode, or if I shut it off if it would ever start again. Your ingenuity will benefit untold numbers of fellow RV’ers. This device is priceless, ask my wife!

  26. Jerry Pate says:

    Looks like the CAN bus interface boards are sold out and they are not accepting orders at this time. Are there any second sources for the processor board with CAN bus interfaces. Thanks, Jerry 210921

  27. B Steelman says:

    Hello, thanks for this information. I have one question. Can the software be installed in the Arduino Due Board without the CAN Bus interface attached to it?

  28. Debbie Rackley says:

    I ordered all items last weekend and today I got the circuit board.

    I followed the instructions closely, the programming part was over in about 2 minutes from downloading the files to programming the Arduino board.

    The mechanical assembly was very straightforward, I mounted my circuit board on 3 small nylon spacers with retaining screws (size 4-40). Plan out the cable route and do remove a few strands from the V+ and Gnd wires. I had to drill a 3/4″ hole for the cable gland I had. I’m going to cable tie the emulator box to a frame member if I ever need to use it.

    I ran the Bus yesterday, so I knew we did not have any error codes. I connected the emulator, started the engine and let it run for about 5 minutes and got no error codes. Yippee! One pleasant surprise was our Allegro Bus is the first year of the glass dash and the dash showed the proper DEF fluid level and proper DEF temp when the engine was running.

    I shut the engine off and reconnected factory configuration and restarted. No error codes.

    I believe this is the best $150 I have spent in a long time. We leave in 2 days for a 2,500 mile 6 week trip so this provides a lot of peace of mind.

    Well done developers!!!!!!!

    Do you guys have a way where I can send you some “Thank You” money????????????

    • Archer2 says:

      No money required. We are just happy that you were able to get some peace of mind for your trip. If you frequent any of the RV boards and have the time, it would be great if you could relate your experience for the benefit of possibly those folks who would like to build a DSS but are not as confident in their ability to handle it.

  29. Jim Brant says:

    I had to get the Aduino-Duo.Core-B board because they were out of stock on the first board you had listed. I am trying to program the ECU and when I run the command it tells me No Device found on COM7. That is the COM Port it is attached to. What am I doing wrong?

    • Archer2 says:

      Hi Jim, I’m not 100% sure what board set you have but it looks like you are saying you have an Arduino DUE (not Duo)? Also the Due also requires a CANBUS shield. Can you tell me what CANBUS shield you have? But, as far as your problem, if you do have an Arduino DUE look carefully at the picture in the Quick Build section. The DUE has TWO USB connectors on the same end of the board that the power connector is on. You need to plug the USB cable from your computer into the USB port CLOSEST TO THE POWER connector. Then recheck what COM port your computer assigned to it as it will probably not be the same as before. Then retry loading the firmware.

  30. Jim Brant says:

    Thank you for responding and sorry about the miss print. I do have the Arduino DUE based ECU Development board with Two CAN Bus Ports. part number JCOM.DUE.CORE-B. This morning I plugged on the board using standard USB cable. the board showed up on Port 8. I opened up CMD promt and typed the command string. Got Message board was not found. I checked in the Device manager and it changed to Port 9 with a different name. So then I typed the command using DUE 9 and it completed the program process. I purchased 4 boards and had to do all of then the same way. Hopefully they are programmed correctly.

    • Archer2 says:

      Hi again Jim. I’m going to post here for the benefit of others who might have substituted the same board as you did. So, Jim got a slightly different DUE-based board than the one we used in the Quick-Build instructions. The one Jim got was a JCOM.DUE.CORE-B from Copperhill. It comes with only one USB port instead of 2. It comes with a cable that is a USB on one end but a 6-pin UART on the other. That cable and connector cannot be used for programming the Arduino, you should use the USB port with a standard USB cable.
      Here’s a link to the CH page for comparison

    • Archer2 says:

      I failed to make clear in the last post that the board Jim has should work just fine. There are just a couple of minor physical differences from the one in the instructions.

  31. Mathis Weatherall says:

    Hi. I’m interested in building the DEF simulator. Thank you! Will this work for my 2017 Newmar Dutch Star on Freightliner chassis?
    Or is this only for Spartan?

    • Archer2 says:

      Hi Mathis. The short answer is that, yes, if you have a Cummins engine using a CM2350 ECM then it should work fine. BUT it appears that most if not all Freightliner chassis use a different physical connector between the sensor and the wiring harness than the Deutsch DT-04 shown in the instructions. That’s not a showstopper but you would need to source the right connector (there is info in the Comments so just look for it) and then figure out which pin carries which signal (ie +12V, GND, CAN_H & CAN_L)as we have conflicting info from the documentation we’ve been able to see.

      • Ardis Almond says:

        On my 2014 Winnebago Itasca Ellipse on a Freightliner Chassis (built April 2013) my connector is a 6 pin flat connector, with the wires colored as pink, green, yellow, pink, (no wire), and black with white(?)stripe. There is obviously 5 wires here, not 4. What next?

        • Archer2 says:

          Hi Ardis. Two things here. The first thing is that sounds more like the connector that goes to the remote DEF gauge, not the connector that goes from the DEF header to the wiring harness. But second, and more important is that your year chassis does not appear to be one that has a high likelihood of failure. Before you go any further you need to contact Freightliner to determine if your DEF header has all three sensors (temp, level and quality) and does it use a J1939 data bus? If the answer to either of those questions is No then the DSS is probably not for you. Good luck.

  32. Chris Glaze says:

    Love this idea! Do you have a phone number I could contact? Thanks.
    2020 Dutchstar Freightliner Chassis

  33. Paul Murray says:

    This is the way the world should work! Funny that even without regulation creators foresight and the manufacturers spineless attempts to force a solution, American ingenuity is alive and all these manmade obstacles can be overcome when us engineering geeks put our heads together. I would hire these guys in a second! Problem solving at it’s finest!

    The “Regulators” and their enablers love their power over the populace and should be embarrased by a simple solution from the masses.

  34. Rob A says:

    Fantastic, thank you! Where will info and a link to the Mac install version be posted? Just keep checking back on the Quick Build page?


  35. Lionel Robert says:

    Thank you for all you have done on this project. Can i use 20 gauge tinned copper for the cable on the simulator or should I go with a heavier wire. What is the 12 volt load on the simulator.

    • Archer2 says:

      The total current draw at 12volts dc nominal should be less than 300mA or 0.30 amps. And yes 20 gauge wire will be fine and a lot easier to assemble especially if you are using a DB9 connector.

  36. Mark Weber says:

    Hello: I have a single seed studio CAN bus board and I also have a few Mega boards laying around. Can I use this set up? I will provide my own regulator for the 5 Volts. Looks like you included a couple of extra folders – one for DUE, one for MEGA and one for UNO so maybe I can install by changing the call?

    • Archer2 says:

      You absolutely can use a Seeed shield with a Mega2560. Just follow the same instructions on the website for the UNO (including cutting the P1 trace to disable the termination resistor). The command line to program should just use “atmega” (all lowercase) instead of “UNO” and add the correct COM port. It works exactly the same.

  37. Larry Brons says:

    I purchased the Arduino-Due-Based ECU Development Board With Two CAN Bus Ports. I read the comment about not using the included 6 pin usb cord. I have a micro USB cord from another device, will that work? I plugged it into the board and the other into my Windows 10 PC. It’s not showing up in the Device Manager window. I’m not too tech savvy, where do I go from here? When plugged in, it appears to power the circuit board.
    Thank you

  38. Joe Zinkel says:

    Wondering if you or anyone has experience with this on 2018 Cummins 340?
    When I Look at my DEF tank, the head is nothing like you show in your photo ( recessed into tank), and as such the plugs look different.
    There is a yellow/black 4-wire plug that comes from center of head area, not sure if this is the same
    Wire colors leaving plug are gray, yellow,black,green

    • Archer2 says:

      What is a Cummins 340? Is that a Motorhome? Do you have a picture?
      I’m kidding but what year, make and model of vehicle? What kind of chassis? Seriously, do you have pictures to show what you are talking about?

      • Joe Zinkel says:

        2018 Pace Arrow 38k with Freightliner Power Bridge

        Can Pic be attached somehow?

        • Archer2 says:

          If you can’t post a picture here then sent it via email to

        • Archer2 says:

          OK, you have a Cummins ISB 6.7 340HP and we know that it will work. The trick is to figure out the connector that FL used. The connector is a
          TE 1-418390-1, this part number is the harness-side female connector. The part number for the mating male connector is 1-703818-1. Here is a link to its catalog page. The first digit, the “1” is important because there are 4 versions and they are not interchangeable. They differ in the color of the insert and the first digit (1, 2, 3 or 4 in the first position). What we really need is for someone to figure out and post here the correct wiring info for the 4 pins.
          Here is a video showing how the connector is assembled

          • sevd says:

            Thanks for the FL connector (housing) info! I have to visually confirm if my 2017 Monaco Diplomat 43S (FL) has the same connectors listed. Then I’ll wait for someone to identify the wiring info for the 4 pins. I’ve ordered everything else I need (UNO+CAN version) except for the 14/4 cable. (I assume any automotive grade 14 guage/4wire cable is fine since I don’t need the DT4 connector for FL.) I got a little confused trying to find the correct connectors that must be crimped to the wires and inserted into the connector housing listed, as well as the special tool to unlock the housing if you need to remove an incorrectly placed connection. Oh, and hopefully I won’t need that special AMP crimping tool — #91337.

          • Archer2 says:

            This is a general response to clarify something about the suggested parts list. Some of the items were specified, not for any technical reason, but instead because the part was available and simplified the building of the unit. The cable/connector is a great example. The cables listed are just to avoid having to assemble your own 4-pin connector or solder extension wires to the pigtails. Not only is it not necessary to use 14 gauge wire for this, it’s not even desirable. The power needs for these devices is minuscule so if you have the chance to use smaller wire (like 20 gauge for instance) then go ahead and use it.
            Same can be said for the CopperHill Due with Dual CANBUS and extended power option. The reason it was specified was because it provided easy to assemble screw terminals for the CANBUS and power connection. The DUE was specified, not for any operational reason, but because that was what the screw terminal shield fits on. There is absolutely no disadvantage If you want to use an UNO with a CANBUS shield and assemble your own cables and connectors. It’s just a little harder to put together.

  39. Don Rackley says:

    2019 Tiffin motorhome here with 450 Cummins L9. We left Winslow AZ today and drove to Page (190 miles) with the DEF emulator connected. I did not get any strange readings on the dash (was really checking) and no MIL lights. My previous driveway test was about 5 minute duration.

    The DEF level read correctly on the glass dash as well as the DEF temp reading. I am convinced this emulator is a good.

    Well done guys!!

  40. Eric Gladding says:

    I have a 2017 American Revolution on a freightliner chassis with 450 Cummins. My tank connector is different. It is more square and post are flat. Do you have info on this connector?

  41. chris mooney says:

    trying to program an uno board and all I keep getting is an error message that the file is not found. can someone email me for some assistance

  42. B Steelman says:

    Hello, I have completed the simulator build and programming of the DUE board,both were successful. I am having an issue with with one parameter, the “DEF Quality Sensor Temperature”. It is reading 419*f. The “DEF tank temperature ” is reading 70*f. I have hooked up to 3 other vehicles with the same outcome. This is still giving an ecm debrate code. Did I miss something while programming? Thsnks

    • Vic Chanko says:

      Well that’s odd. What are you trying to connect to? Make, model, year, chassis manufacturer, engine info, ECM info.
      Also what hardware did you use UNO, DUE and CANBUS shield.

    • Vic Chanko says:

      Also, do you have the PGN/SPN numbers for the parameters that are out of specs? The DSS doesn’t send any data for “Quality Sensor Temperature” and that specific parameter description does not appear in the SAE J1939 standard that I can find.
      PS, I see you used a DUE. Is it the one from Copperhill that is in the instructions or is it something else? Does it have the Copperhill “Dual CANBUS with extended power” daughterboard?

      • B Steelman says:

        Yes, I am using the Copperhill board as listed in the build instructions. Vehicle application is an Eldorado Transit bus 2018 with an ISB 6.7 CM2350A. DEF unit is the Shaw Development unit, same as most coaches use. Fault codes 6255(Cummins)
        SPN 1569. All others went inactive related to DEF quality.

  43. john briese says:

    Thank you so much. Great peace of mind. Any comments on storing this for later use?

    • Archer2 says:

      Glad your project was a success. As far as comments on storing for future use, yes. Store it someplace where you will remember where you stored it!

  44. 5511564 Cummins def header sensor
    We have a Cummins Motor attached to a truck that needs a new DEF Header Sensor as noted above. Will this DEF Sensor simulator work for this application.
    Cummins telling us that it want be available for 100 days.

    • Archer2 says:

      We need a lot more info. Make, model of truck. What engine, which ECM and year the engine was actually built. Will Cummins not perform the emergency recalibration (in other words reprogram the ECM so as to disable the deration inducement in the case of a failed sensor?

  45. Steve Buckman says:

    Question – I’ve built two of these simulators, one of each model. I plugged both in and they appear to function. However, when I plugged the first unit in I had 3/4 tank of def and fluid temp was 72 degrees. The second one I had 1/3 tank of def and fluid temp was 80 degrees.
    Now when I plug either unit in it show what the initial values were when I first plugged them in, i.e. 3/4 tank for one unit and 1/3 tank for the other.
    Question is if my sensor fails and shows zero def and who knows what temp and quality defaults to on a failed circuit – what values will the simulators report to ecu when it’s plugged in?
    I hope this question makes sense to you.

    • Archer2 says:

      Steve, am I understanding that you have two different devices, one DUE-based with a Copperhill shield and one UNO-based with a Seeed shield. Correct? Second are you saying that you are testing them one at a time by connecting them to the EXACT SAME vehicle but getting a different reading on the main DEF level gauge BUT no other fault codes like “SPN 1761 FMI 9”? Does the vehicle have a good, functioning OEM sensor or did it have a failed one? What kind of vehicle is it? Make, model, year and type of engine?
      The reason this is really weird is that while the hardware may be different, the software is exactly the same. The output data from any DSS is identical to every other one. The DSS does not depend on or store any data or values whatsoever from the vehicle, they are output-only devices.
      My guess is that there is something wrong with the one that shows 1/3 full tank and 80 degrees. What I can’t figure out is how it is not functioning but also not causing any faults or warnings. You say that the boards both show that they have power (ie LEDs light up and flash) so we can assume that the +12v and ground is wired correctly (and if it weren’t you would get instant errors) so it only leave the CANBUS wires and if they were reversed you should also get faults. It’s a mystery! Can you contact me at to continue troubleshooting via email rather than using this website?

  46. Richard Mackenzie says:

    Building def simulator using uno board with a seeded can bus my question is about cutting the trace wire on the can bus how do I know it’s been cut is a way to test that it’s been cut

    • Archer2 says:

      If you have a multimeter that measures resistance either measure across the two P1 pads to verify that it doesn’t measure 0 ohms (a dead short) or you can measure between CAN-H and CAN_L. It should measure substantially higher resistance than 120 ohms. Or you could, of course, just use a magnifying lens and visually verify that the tiny little copper trace has been severed. It doesn’t take a whole lot of effort with an X-acto or a box cutter.

  47. Larry E Slate says:

    In comments ” Note: It may not be obvious, but the green part with the screws unplugs from the green part on the circuit board so go ahead and remove those connectors, it will be much easier to attach the wires.” Does the green part lift up or slide out? Is it the entire green piece or just the part with the screws?

    • Archer2 says:

      The green connectors may be separated for easier wiring. They separate at the seam just behind the screws. Hold the part of the connector that is soldered to the circuit board and pull the part with the screws gently away from it. You may have to wiggle the part with the screws back and forth gently to work it loose.

  48. Paul V Campbell says:

    Copperhill Technologies is now posting a long warning/disclaimer on their site relating to the use of their devices for a DSS. CYA to the max.

    • Archer2 says:

      We are aware of that. Copperhill posted that warning coincidentally at about the same time that they sold out of the boards and while they were at the same time scrambling to obtain more inventory. Perhaps the owner was trying to buy time to restock before customers looked for an alternate source. Who knows?
      In any case we obviously strongly disagree with the Copperhill assessment and believe that they mis-characterize the DSS by lumping it into the same category as “Emissions Delete Devices” which it absolutely is not.
      But, it’s their website and they can defend whether the warning is factual or not. We think it is not.

  49. Randy Weller says:

    Has anyone done this for a 2019 Newmar Dutch Star 4369? We are stranded at the Corpus Christie Freightliner shop. The diagnosis is a DEF head failure but the part is not available now and the soonest they can get the part is 38 days, but probably longe. They advise not driving the coach and waiting for the part. If someone has already done this kit, would you be willing to sell it? We are in bit of bind and I’m looking into all options. Thank you and God bless.

    • Archer2 says:

      Anybody who has a DSS with a Freightliner-style connector built who can help these folks out of a jam and loan it to them if they will pay the freight charges both ways?

    • Mark Tallent says:

      I just built one and found out my rig wont accept it – I have an “older” analog system. I’ll sell it to you for the cost of the board ($150) plus shipping – I used the Ardunio – ECU Dual CAN Bus Interface with Diode Dynamics DT 4 PIN extension wire. Wired up in a case and software downloaded – just not tested.

  50. Mike says:

    Will this emulator solution work on a 2018 International with the Maxxforce engine?

    • Archer2 says:

      As far as I know it has only been tested on Cummins engines and 1 PACCAR PX7 which is a re-badged Cummins I think. So the answer is we do not know. You could certainly build one and try it but you are on your own to figure out the connector wiring. It might work and it might not but other than throwing a fault,code or two I don’t see how it could cause any serious problem as long as you have someway to clear codes if the built-in diagnostics don’t do it.

      • Mike says:

        Thank you. If we try it I will post results.3 plus months on municipal snowplow with no eta on part and winter just about here. Have to do something!

  51. Mike Ford says:

    Hi: I would be interested in just buying a box from one of you guys. I have a 2017 tiffin with the 450hp Cummings. I have read that the boards are on back order. Thanks

    • Archer2 says:

      We decided to not sell completed devices for several reasons. We are not manufacturers. In fact, there is not even any formal “Organization”. We are just a small group who teamed up to try to solve an intractable problem. We only provide information and free software based on our own research and experiences. If you will spend some time looking through this website you will find that there are currently 4 different circuit boards and configurations that have all been shown to work. I’m sure you can get delivery of at least one of the options. They range from as much as $150 down to under $20. Each of them has pros and cons but they all work equally well. Good luck.

  52. Wade says:

    In step 1 of “Extract and install the software:” the first picture shows a pair of wires for vehicle power connected but is not mentioned in the directions. I assume that is 12Volt and is that power needed for programing?

    • Archer2 says:

      Wade, you are right about there being 2 power wires in the picture, good catch. The picture is just intended to show the various connection points on the board. That connector will be used later but does not need to be used during programming. The board will be powered during programming by the same USB cable that the programming is done with. The power connection shown and pointed out will be connected later in the portion of the instructions about how to build and wire the connector that will be plugged into the vehicle harness where the existing Sensor is currently plugged in.

  53. Mike Ford says:

    Hi. I just clicked on the #1 option to order the board for the build and didn’t click the power option,I didn’t see an option to click. It was $149 but I hope it is correct. It is on the way. Thanks!

    • Archer2 says:

      Mike, if you didn’t order the extended power option then there is no reason to buy the expensive board. If Copperhill’s policies allow you to cancel the order you should do that. Look for the instructions on this site to use the alternative board, the SeeedStudios CanBed board from DigiKey. It will work just as well, will be just as easy to build and will only cost about $20.

      • Mike Ford says:

        Thanks for replying. The board has shipped already but if it will work I will keep it. Totally computer illiterate so hope it works. I am derated an can’t get roadside assistance,trying to get going again. Thanks you all for doing this for us

  54. I have a MacPro with Parallels and Windows capability. I hooked up the board to COM 3, I extracted the software to C:\AVRprog, I typed in cmd in the run box, and then typed in the command line while changing the 6 to 3. After hitting enter, the info contained in the first box on the instructions with the black background and the green lettering appeared. However, I never had the info in the second box appear. Initially I did no hit a key to continue. After I did hit a key, nothing happened. What did I do wrong? Thanks.

    • Archer2 says:

      Jerry. Which version circuit board are you using? DUE, UNO, CanBed?

        • Vic Chanko says:

          You should be able to use your computer to do this just fine. If I’m understanding what you are doing you will probably be OK. You may have already successfully programmed the board and just not know it but just to be sure follow these directions:
          There are 2 usb connectors on rhe DUE. You want to be in the one closest to the power connector (the Programming Port).
          If that’s correct then type “CMD” then hit enter. That should open a black command window with a DOS prompt. Type next to the prompt “CD\AVRProg” and hit enter. Then type the “program.bat DUE 3” and hit enter. You should see all the install commands scroll by and at the end it should say something like AVRDude completed. Thank you!
          That should do it. There isn’t any “second window”. The screenshots in the instructions just show the beginning of the programming messages in the “first box” and the end of the process in the “second box”.
          Let us know if that clears it up.

  55. Mark Tallent says:

    Hi Gents – My DEF head has 2 individual connectors. One with 3 wires – Red/Blk/Yellow and a second connector with 2 small white wires. Is there an option for this head

    • Archer2 says:

      Hi Mark. That configuration generally means that your sensor is an older, (usually analog or an analog/digital hybrid) design. As far as we know it is not compatible with the all-digital DSS. What year/make is your chassis and engine? Just curious.

      • Mark Tallent says:

        2015 Tiffin Allegro Bus w/Cummins ISL9 450 hp. I’m not having a DEF head issue but was planning to carry the simulator JIC. Maybe this year/model is not affected by the failures?

        • Vic Chanko says:

          Correct. DSS will not work in your setup but yes, your setup is not known to have the same problem as the later all-digital sensors.

  56. mike says:

    Need the build files for Mac OS X

  57. Bob Divins says:

    ATMega 16U2 DFU shows up in other devices but not in Ports on Device Manager. The device has no driver and is not configured – any ideas? Windows 10 32 bit OS

  58. Terry Snodgrass says:

    My plug/connector is a 3 pin (horizontal) is there another option ?

    I have the kit built and ready to plug in and just discovered the different connector plug coming off the top of the DEF tank.
    2015 Cummins ISL 450 Tiffin Allegro Bus.

    • Archer2 says:

      Hi Terry. Well, we have good news and bad news. The bad news is that your sensor appears to be an analog system (pre-2016) and the DSS will not work. The good news is that you are not likely to have the problems that the DSS is able to help with.
      I wish I had a better solution for you.

  59. Stan E Malinky says:

    HI to the development team and thank you for all of your work on this project.

    Failure: DEF Low, Yellow Lights Just serviced the DEF tank and we were in the process of taking a trip and the failure happened in the driveway.

    What I have:
    2020 DutchStar build date August 2019, Chassis XCR, Engine L9 450RV HP
    ECM 2350A with latest updates

    What I did:
    Ordered all the parts for the Quick Build

    Programmed the board with success (Verified with DEF Tank level at 74% when DSS connected)
    Built the cable with the Freightliner Amp connectors
    Verified cable by plugging it in and measuring the Voltages Verified (I did notice that the voltages were 2.5 and 2.7 on Can-L and H)
    Wired the cable to the Board and ohmed the Amp connector to the board connector Verified.
    Plugged it in and went thru the process to clear the code (Start 3 times) and just the check engine lite went out the other DEF warnings were still on (Low DEF)

    Onboard Diagnostics menu currently unavailable.

    Ordered the scan Gauge and could not clear the codes
    Tried with the engine off, key off and codes cleared but as soon as I started the engine they came back.

    The current code is SPN: 3364 FMI: OC:1 SA:0

    My next test will be drive it around my neighborhood to see if it will go into derate then limp back if it does.

    I have an appointment at Freightliner December 1.

    Just wondering if there is anything else I can do?

    Again thanks for all of the hard work,


  60. Born2camp says:

    I completed the Arduino Due build for Tiffin Allego bus 2017, and it worked great for about 7 hrs driving time. Then the dash lights came back on and got the 3 DEF codes. Checked the board power light and it was on. Does the ECM monitor the DEF flow? And does the simulator have a constant fixed DEF level? Any idea why the lights/DEF codes came back on? This is a Powerglide chassis, 2350 ECM.

    • Archer2 says:

      Hi, thanks for telling us about your experience. My thoughts would be that (1) something has happened in the wiring or the cable (loose connection, 2 wires shorted by a stray wire whisker, etc.), or (2) something on the circuit board has failed and it is no longer operating. Was the board subjected to any unusually high temps? Are the codes you are getting SPN 1761, 3364 and 3031 all with FMI 9? Are any other LEDs in addition to the power indicator lit or flashing, like the two that indicate CANBUS activity?
      Were the 7 driving hours all in a row without any shutdowns or restarts or was it over a few different trips?
      If the circuit board has failed, my suggestion would be to buy a Seeed CANBED board from DigiKey for about $20 and salvage/repurpose the cable, connector and enclosure. The instructions are on this website.
      If you want to go to the trouble and expense of shipping the unit to one of the devs we could put it on the bench in a test setup, but if it’s dead it’s not readily repairable anyway. If you want to do that then please post again

      • Born2camp says:

        Thank you for your prompt response.
        The driving hours were in 3 legs, 3 hrs, 3 hrs, and then 1 hr into the 3rd leg the failure occurred. The board/box is mounted about 2.5 ft above and to the left of the engine. The codes were the 3 you said with the FMI 9. As regards the board, the power light is on, the “NC” light is green, and the “L” light is amber, could be flashing very fast.

  61. Jim Leibold says:


    1st off, thank you to the developers and all contributors on this project – a wealth of information has been provided.

    I have “finally” received all of the parts necessary to make the build, at this point my only question is regarding the programming. Is there a set of files now that can be downloaded to mac? (by that, I mean without running windows on the mac desktop) or, is the preferred approach to still utilize a PC/windows laptop for programming.

    Thank You!

  62. I am a newbie owner of a ’21 Entegra Cornerstone, 605HP Cummins, and wondering if I should be concerned or if the issue on DEF errors has been remedied on the ’21 models?
    This looks like a great fix that maybe I can figure out how to do properly if I can get my hands on a PC as everything we have is a MAC product.
    Thank you!

  63. Les Bergmann says:

    I’m having trouble connecting to my PC. Plugging the board into USB port brings on the lights but It doesn’t show up in the device manager. I recently upgraded from windows 10 to 11. I’m wondering if that may be the issue. Or possibly the boards bad. I’ve tried different USB ports and changed cables. Instruction say you must have one 2/3 USB port. I’m not familiar with a 2/3 port. My thinking is that this means either a 2 or a 3 port? Thoughts and or recommendations would be appreciated.
    Les Bergmann

    • Archer2 says:

      Hi Les. You don’t say which board you are using. First, you are right that the USB 2/3 refers to needing a USB 2.0 OR a USB 3.0 port. Second if you can test the cable by using it to connect some other USB device like a camera or printer or even a mouse to your PC to see that it works properly, making certain that’s it is not just for charging devices. Lastly, if at all possible try to connect to a different PC just to see if it appears in that PC’s Device Manager. But it is also possible that your Arduino board is defective. I have had one CanBed board that was DOA. It would light up the lights but the USB port was dead.

      • Les Bergmann says:

        Thanks for getting back to me. I’m using the CanBed board. After reading some more posts I realized the cable I was using was not appropriate. Ordered the one specified and now all is good. I guess an old dog can learn new tricks.

        Thanks again.

  64. Keith says:

    Can someone answer this question for me please? After programming the canbed I have the blue light blinking but also have two red lights on. Is this normal of a problem? Much appreciated if some can answer,

  65. Clyde Spero says:

    is the sketch available to share?

  66. D. Stallings says:

    I have a ’21 Entegra Cornerstone with the 605 Cummins, and was unable to get Spartan to tell me if what I have is a new gen that won’t fail on me. They also said they don’t know how many or if any of my model has failed. I went ahead and ordered all the parts (the links were very helpful, thank you) and one part was on back order and another was about 2 – 3 weeks out. Since I was headed on a 2000 mile trip shortly I was going to be worried the whole time. So for peace of mind, I bought one from a guy that had two of the DEF SIM units so I would have one immediately. Upon returning from the trip, I borrowed a laptop from my daughter (since all my stuff is Apple) and we were able to follow your directions to the “t” and successfully downloaded the file. Built the box in about 10 minutes and everything fit perfectly. For retention of the board, I used small pieces of foam tape to the sides of the box holding the unit in place along with the tight fit which made everything tight. Thank you SO MUCH for this! I truly admire ya’ll putting this info out there for all of us to benefit from and have peace of mind.

  67. Brian says:

    Can someone answer this question for me please? After programming the canbed I have the blue light blinking but also have two red lights on. Is this normal of a problem? Much appreciated if some can answer,

  68. Brad Poff says:

    Are directions for software install using a MAC available yet??

  69. DL19 says:

    Hi, I only use mac. No window software available. I thought I’ve read somewhere that you were going to post how to use mac to install the software but I can’t find it anywhere. Could you point me out? Thanks for all the works you do.

  70. Anthony Flores says:

    Archer 2
    When I first connected the canbed to the USB port, 1 light stayed on steady ner the connecter and another light would flash near the reset. After making several attempts to get the program loaded I would get unable to to download file to ComX.
    I was using Com 3. Now none of the lights come on or flash. Did I cook the canbed or is there a way to bring it back to life?

  71. Robert Kienlen says:

    Hey guys – I’ve got a 2016 Newmar Ventana DP with Frieghtliner XCR chassis, built in 11/2015. Have been reading the posts on the Arduino DSS build,and have also ordered all the parts.

    However, when I look closely at my Sensor head, I do not find the 4-pin rectangular Can bus connector, or any cable that has this connector on it. I do have a flat, 4-pin connector that plugs into the top center portion of the head, but no 4-pin rectangular connector as pictured in the instructions.

    Does this mean I have the older, analog Sensor, and don’t need to build the DSS?

    Thanks, Robert Kienlen (Dallas, Tx area)

    • Archer2 says:

      You are right, that style connector was for the pre-2016 version that uses a sensor that is not as prone to failure as the newer sensors.
      Please keep an eye on the forums here because I just noticed that the CanBed boards are now sold out and back ordered at Digi-Key so I’m sure you will be able to unload your unused parts easily.

  72. Larry D. Lawson says:

    I have downloaded the software and followed the instructions. When I get to the part to install on my Arduino R3 the software tells me that they cannot find the device on com 3 port.

    2019 Allegro Bus
    450 cummins Powerglide chassis

    Thanks for any help.

    • Archer2 says:

      Larry, can you verify that your USB cable is not a charging-only variety? All 4 wires in the cable need to be connected end to end or the cable will not communicate data.
      Check your email for a message if you still need assistance.

  73. 204maker says:

    I was trying to build the def sensor simulator using my available components:
    -Arduino Uno
    -MCP2515 CAN Bus Interface Module

    I connected the MCP2515 CAN Bus Interface Module to Arduino UNO using the SPI pins except for the INT (interrupt) pin, then power (+5V), and GND.

    I was able to program the Uno successfully on COM Port 6 using the command:
    C:\AVRProg>program.bat UNO 6

    I opened a serial monitor to check the serial data on COM Port 6 coming from Uno to the computer, and I get these values:
    CAN init fail, retry…
    CAN init fail, retry…
    CAN init fail, retry…
    CAN init fail, retry…
    CAN init fail, retry…

    It looks like an error with the CAN communication.
    May I ask what would be the wiring setup for UNO to build the simulator?

    • Archer2 says:

      There is an entire section on this website with instructions for building a DSS using an Ard UNO with a Seeed CANBUS shield. If you want to experiment with other hardware good for you and good luck but you are pretty much on your own. Here’s the website link to the instructions
      I will say that you may not really have a problem anyway. The way J1939 works means that unless the unit is connected to a real, working J1939 network it can’t execute the address claim process and will hoasically just stop trying after a short time. But that’s just spitballing.

  74. Larry D. Lawson says:

    My DB9 connector only has numbers and does not indicate the position for the +12, can l, can h or the gwd.

    Help again.

  75. Irv Hoerr says:

    This a great thing if I could get it done, would be great to have onboard my Tiffin with a 450 Cummins.
    I purchased the Arduino Due and other parts last year when this Quick Build came out. I am getting ready to head north for the summer and am just now building my unit. I have downloaded the DEF Sensor Simulator Install Files but can’t get it to extract onto my hard drive. After about 15 minutes it has an unexpected error and closes. I have tried redownloading, rebooting, and even a different computer and can’t get it to fill the bar on the extracting page. I do see the AVRprog folder and sub folders on my hard drive. Never got a Run box to type cmd in or a command prompt windows dialogue box. Is it possible the exe file I am downloading is bad?

  76. Dana Rodakis says:

    Will this work for a 2020 Tiffin Allegro Bus? Is the DEF head part of the tank?

    • Archer2 says:

      Yes, it should. Tiffin uses the DT04 connector that is shown in the instructions. Also yes, the DEF Head is part of the tank assembly but is removable. But that really is not relevant because the DSS device is just plugged into the same connector that the DEF head is plugged into. You do not need to remove the existing head from the tank. Please read the instructions, they should be clear on what the process is.

  77. after i extract all downloaded files i do not get a box that says run the files are in cdrive please hilp

  78. please help i cannot get a box that says run

  79. Robert Kienlen says:

    Full set of new DSS parts for sale, exactly as described in this Forum. Bought them for my 2016 Newmar, but have since learned it has the older model DEF sensor, so not needing to build the DSS.

    Selling parts as a complete set only; all parts new in the box. Includes the Arduino UNO board, the CAN shield board, a female DB9 connector, an enclosure box, and a DT4p 1-meter extension cable. $125 shipped within the U.S.

    Robert K. (Dallas, Tx)

  80. Thomas Thompson says:

    Thanks for all your hard work.
    Question: In picture 10 you state to remove the 2 jumpers but when you get to picture 11 the jumpers are still on the Arduino. So do I remove the jumpers and leave them off?

    • Archer2 says:

      You can remove them completely or, as shown in picture 11, you can rotate them 90 degrees just as a way to keep track of them in case you ever need to use them again (although I can’t imagine why you might need to do that). The main thing is to break the connection between each pair of small pins.

  81. RFS says:

    I programmed two Canbed boards – following the instructions, both boards took the programming OK. I tested them by turning off the chassis batteries, plugged them into the cable in place of the def head, turned power back on. The def gauge dropped to 3/4. as you said it would – started up the engine – no warnings or codes appeared. I will stow them away in the coach, 2022 Tiffin phaeton 40IH 450 HP, as a “just in case”.

    Thank you and others for the great work.

    • Archer2 says:

      Congrats, nice job! FYI it’s not necessary to completely turn off the chassis batteries. Just make sure the ignition switch is off. The DEF sensor gets power when the key is turned on to the accessory position, so just make sure the key is off before unplugging anything. It IS a good idea to wait a couple of minutes after turning the key off before unplugging things just in case there is a delay before power is removed to allow for line purging etc.

  82. wes walker says:

    Thanks for all the information regarding the def sensor simulator.
    I am in the middle of the build and am having trouble with programming the canbed.
    I type cd\avrprog and click enter. I see the command prompt C:\AVRPROG.
    After entering: program canbed 4 I get the following on my pc screen.
    can’t open device \\.\com4: the system cannot find the file specified

    Any help would be much appreciated

    • Archer2 says:

      Hi Wes. In the command line you want to use the port number that Windows switched to for a few seconds after you press the reset button on the board. So first you watch Windows Device Mgr when you plug the board up, it will see the device and assign a port number. Then press and release the board reset button and watch when Windows assigns a new, temporary port number (usually 1 higher or lower than the initial assignment). This second, temp port number you need to use in the “program canbed X” line.
      So plug the board up, type “program canbed X” where “X” is the temp port number. Press and release the reset button, wait 2 seconds to give Windows time to reconnect and then press “Enter” on the PC. This info is in the instructions but you have to read them carefully and follow them step by step.

  83. ML Wilson says:

    2019 Ghost 33DS, Cummins 6.7,360HP 1st DEF failure April one year ago. Int’l replaced/repaired sensor. I replaced the coolant valve with the newer brass valve. Ordered parts to build emulator. Excellent instructions. Installed software, no issues. TODAY, for the 1st time, I installed the emulator for a test before hitting the road again. First, I topped off the DEF tank, verified that the gauge read full. Connected the emulator and after starting the engine, DEF gauge went from full to empty, and check engine light. Double checked my wiring. Do I reinstll S/W or order a new board OR ….??

  84. L H Richey says:

    When are trying to figure out which one of these boards will work for a 2014 Tiffin Red with the 340 hp engine.
    Any Help or information will be kindly accepted and appreciated.
    Thank you very much.
    L H Richey

    • Archer2 says:

      Hi LH Richey. Engines produce before 2016 are of a different design and are not particularly prone to failures as far as I know, unlike the 2016 and newer designs. I do not believe that the DSS would work but I do not really know that for sure. If you feel like experimenting here’s what conditions need to be met:
      If your current Sensor has 4 wires (and only 4 wires) that connect to the vehicle wiring harness AND it uses a SAE J1939 standard CANBUS to communicate with the ECM AND you can determine what kind of connector it has as well as which pins on the connector are +12V, Ground, CAN + and CAN – then it might work-but it might not. If it uses a J1939 CANBUS then I don’t think it would be damaged if the DSS were attached. The worst case situation is that it would just cause whatever fault codes you would normally see if you just unplugged the OEM sensor or the OEM sensor failed.

  85. Randy Boyer says:

    Have you posted the work around for using a MAC yet? If so, how can I find it? Thanks for all you are doing!

    • Archer2 says:

      Here is a cut & paste from the Comments on the FAQ Section of the site. I personally don’t know anything about using an Apple Mac, Flyboy013 is the expert on all things Apple, but I know that a couple of people have used these instruction successfully. So here’s the excerpt but there is some further discussion in the FAQ comments section that you can read as well.

      “Flyboy013 says:
      October 19, 2021 at 9:11 pm (Edit)
      The installer has been uploaded to the GitHub site ( The file name is DSS.dmg

      I have not yet had the opportunity to generate the installation guide for it. In short, you can download the file (DSS.dmg) and double click (ie. mount the image) it. A folder will open showing its contents. You will see an file. Right click on it and open it with Terminal (may have to select Other and then Terminal). It will run the install script and prompt you type of device. Connect the device and then press the button for the appropriate device type. It will give you another popup showing if it was successful.”

  86. Robert Glover says:

    I am building a simulator using the Canbed design. Would you expect the 4 pin cable in the parts list to be compatible with a 2020 Tiffin breeze 6.7 Cummins power glide chassis? Thanks!

    • Archer2 says:

      Yep. The cable and connector from Diode Dynamics will work fine. It is noted in the instructions somewhere that it is a good idea to trim some strands off of the red & black stranded wire in the cable so that it is a better fit into the small screw terminal holes in the connector that gets soldered onto the CanBed board. They come as AWG 12 or AWG 14 but they need to be more like AWG 18 or 20. Trimming them makes it a lot easier

  87. Jim Slaughter says:

    I built one of the Cantù’s sensor simulators and everything went smoothly and software downloaded just as it should. I have a 2013 Itasca Meridian 36m with a ISB Cummins 360 turbo, and still not really sure where this would plug in if it debates on me. Any help would be appreciated.

    • Archer2 says:

      Hi Jim. Congratulations on your build but I’m afraid I have some bad news. As has been explained many, many times here, the DSS only works on engines built in 2016 and newer. Your sensor is an analog device and is completely incompatible with the digital DSS. It is not just that the connectors are different. The entire theory of operation is different.
      Good news is that your version of the sensor is not especially prone to failure. If you like, you are welcome to post here if you would like to offer to sell the one you built to someone.

      • Charlie Greeley says:

        Hi. I am very new to this topic and the stream of questions and answers. I have a 2016 Dutchstar, purchased last year. I apologize for asking such a simple question, but how do I determine if I have an analog or digital sensor? Feel free to reply privately to my email, or direct me to the answer if this has already been answered/commented on.
        Thank for the service you have provided!

  88. Kenny Lee says:

    I bought the CANBED board and I’m trying to install software but I keep getting “no device found on COM 3” I have changed ports and cable and still the same. any thoughts?


  89. Greg Rickman says:

    Hi there, thanks for inventing this invaluable piece of equipment! I have a question from 3 of my friends (I already have mine). Will this work on the following motorhomes: 1. 2022 Newmar Ventana (L9, 400HP Cummins), 2. 2022 Tiffin Allegro Bus (ISL9, 450HP Cummins) and 3. 2021 Tiffin Phaeton, ISL9, 380HP Cummins). Thanks in advance, I just want my friends to have one of these!

    • Archer2 says:

      Make sure you use the correct connector depending on whether the chassis are Freightliner, Spartan or PowerGlide. Other than the connector, the devices are the same hardware and software.

  90. Vincent says:

    Very interested, and excited to find this. I work for a heavy equipment dealer, and we currently have Cummins powered paver that turned into a paper weight for the next 3 weeks while we wait for a Def header. I’am going to make one of these and see what It’ll do. Perkins engines use the same shaw def header, So I see a big use for this. Will report back on what engine’s and systems I can use it on. I can get wiring diagrams for most of the different variety of and I have a large stock of pig tail’s from all the failed units. Have you noticed if most manufactures use the same communications methods on can for there def headers? I personally have only seen about 3 or 4 different manufactures of def headers, Then they have different sizes. Seems like they should all work about the same. Thank you none the less for providing a nice stop gap fix!

    • Archer2 says:

      Interesting. Please let us know what you find out. The CANBUS data messages to and from the DEF Sensor are all specified in the SAE J1939 standard for Heavy Duty Engines so they should work. The only connections are +12VDC (nominal), Ground, CANBUS + and CANBUS -.

  91. RS says:

    I found that DigiKey and CopperHill don’t have the connector parts for Freightliner XCM. However, I found all 3 components at The downside was the connector pins shipped from the Netherlands and it cost $22 to ship $2.49 worth of pins. Oh well.

  92. Antonio says:

    Is there a DEF sensor simulator for an Isuzu HD diesel.

    • Archer2 says:

      Sorry but while it might work there are a number of criteria that would need to be met. We have no information about Isuzu trucks. What year? What parameters are monitored? Does it utilize a SAE J1939 data network? Which PGNs are used in the DEF monitor? What kind of connector does the sensor use? If it is a J1939/CANBUS system can you identify the connector pinout? Is it a 250kb/s or 500kb/s data rate?
      About all I could suggest is for you to read all the info on the website and build a DSS to experiment with if you think your vehicle might benefit. Sorry we can’t be more help.

  93. Mark Jasmer says:

    I exicuted theDEF Simulator Install files v0.2 (x32) Checked path on my PC placed it in C:AVRProg (default location) then plugged my CANBed v1.2e into usb port and it automatically programmed the CANBed. I have a green power indicator and a blue flashing led by the reset button. Can I safely assume the board is programed when it has this flashing led?

    Windows 10 OS CANBed from longan

    • Archer2 says:

      No, there is no shortcut in programming the board. You appear to be saying that the board programmed itself after you plugged it in and that is not possible. You must follow all the instructions for programming the board ESPECIALLY THE INSTRUCTIONS ON DETERMINING THE CORRECT PORT NUMBER TO USE WHEN YOU TYPE THE PROGRAMMING STATEMENT (ie “program canbed X”) in the Command Prompt window.
      Read the instructions carefully and do what they say, step by step. Don’t skim and skip, do each step exactly as described.
      Also, there is no CANBED board that uses the WIndows 10 OS so I dont know what you are trying to say there.

  94. Jeff H says:

    First of all, thanks to the development team!

    I apologize if this has already been asked and answered. I skimmed all of the previous comments and didn’t see it.

    Is there any reason why the simulator cannot be connected to the CAN bus at the diagnostic port under the dash, after unplugging the actual DEF head, of course.

    This could help those of us on a Freightliner chassis because the green 9-pin diagnostic connectors appear to be more readily available than the Freightliner DEF head connector. It would also keep the simulator out of the heat and grime.

    • Archer2 says:

      That is an excellent question. The original idea was to do just that but we were not able to make it work. It looks like the data that appears on the diagnostic port is somehow buffered or proxied or curated (take your pick of terminology). For instance, the real J1939 address of the DEF sensor is 0xA3 but when you look at the PGNS containing the data from the DEF sensor at the service tool connector port it shows up as address 0x00, which is the address of the ECM. Another issue is that the Service tool connector runs at 500kHz while the emissions data network appears to be a separate CANBUS network running at 250kHz (which might be why the ECM is needed to be in the middle).
      Anyway, since we knew that we could connect directly to the CANBUS by using the OEM sensor connector, for our purposes it minimized the problems and wasn’t worth exploring further.
      Not to say it couldn’t be made to work but it will be up to others to figure it out. If you want to tackle it I think I can speak for the developer group in saying we would be happy to cooperate with your effort.

      • Jeff H says:

        Thanks for the reply. I did a bit more googling and found one reference to Cummins having a separate CAN network for the exhaust aftertreatment system. This certainly agrees with your finding of different data rates and source address for the DEF PGNs. I think that we’re stuck with the OEM sensor connector.

  95. Russ says:

    I can not fond s arduino due board. Copperhill says they never sold them
    And sent me to digikey who is trying to find something that will work

    • Archer2 says:

      While it takes some reading on this websit and it may be a little confusing, there are currently 4 different hardware platforms that will work, each with their own instructions. They are: 1. the DUE from Copperhill with their proprietary extended power option. 2. The Arduino UNO with CANBUS shield, 3. Arduino atMega2560 with CANBUS shield, 4. Seeed (Longan Labs) CANBED development board using the atMega32U0 microcontroller.
      Then there is a brand new option using a Seeed CanBed development board using a Raspberry Pi RP2040 controller, full instructions for the RP2040 will be available on the website in the next day or so and the Seeed CanBed development board using the M4 controller, the instructions for which are in the comments somewhere. Use the search tool.
      If you can’t find some kind of hardware to use given all that, well I don’t know what to tell you.

  96. Gary Maniscalco says:

    I want to thank the development team for putting this together. I completed my build a few days ago and ran it this morning. Started with no faults. Ran for ten minutes no faults, then shutdown for about 15 mins. After I hooked back up the OEM connection and ran the RV for 10 min I still had no Faults. I have attached the board to the box with Velcro, but am also exploring other methods. I had extra magnets from my MagnaShade installation and am going to use those for attaching the box to a metal panel next to the DEF tank.
    I want to thank Flyboy13 for the Mac Install packet. It worked great and did not require any intervention as the Windows does.

  97. TJS says:

    The ECM search came back as CM2450 on my ESN. Will the current version of the Arduino DUE with CAN Card software and instructions work with this ECM?

  98. Kenny Lee says:

    You guys are the best…I had the unfortunate three lights I didn’t want to see today MIL, Check Engine, DEF. Thankfully I built a bypass and hooked it up and seems to work…will know more tomorrow when we drive.

    My MIL light is still on is this normal?

    2017 Tiffin Phaeton 40IH

    • Archer2 says:

      The MIL should go out after 3 cycles of the engine running for at least 5 minutes. On the 4th key-on cycle all codes should automatically be set to inactive and all lights should be extinguesd. The SPN1761 and SPN3364 are already set to inactive. It’s just SPN3031 that requires the 3X 5 minutes process-it’s an EPA thing.

      • Voltdoc says:

        However, in some cases like my 2017 Spartan K2, 3031 will not clear with ignition cycles, I’ve always had to clear it manually, a Bluefire device works fine for this.

  99. Jason Collins says:

    Thank You all for your efforts in the creation of this device. Our sensor failed at 9,733 odo this past friday just before leaving on a trip. I had built the device last year and had it stored on board. After connecting the DSS we were off and happily motoring down the road. The MIL went off after the 3 start scenario. We have a 2020 Navistar International MV607 with Cummins 6.7.

  100. Andre says:

    I was able to successfully build the simulator using the CanBed ATmega 32U4 board. The board says it is suitable for 12V or 24V systems. Would I be able to use this simulator for a 24V system? Does it have to be coded or wired any different?

  101. Thomas Buzzell says:

    Has anyone tried to build the DSS using a CanBed Dual with the RP2040 processor? I had a spare CanBed Dual board and tried the same steps as the CanBed RP2040 (which I have successfully built), but when the file starts to copy, it closes down the Windows File Explorer, but the only light on is the power light.

    • Archer2 says:

      Hi Tom, glad you got the RP2040 programmed. As to your second question, technically there is no reason that the dual-channel RP2040 board wouldn’t work BUT I don’t believe that it will work with the existing DSS software. The issue is that the dual channel board uses a microcontroller to handle the low-level CANBUS data traffic and the single-channel version uses a couple of linear chips and the two approaches require different software libraries. To support the dual-channel device would entail a software rebuild and that in turn would require additional testing.
      Since there is no benefit to using the dual-channel RP2040 there is no reason to go through that effort.
      Good luck & safe travels

      • Tom Buzzell says:

        Thanks. Just wanted to check as I ended up with the board at no cost and really don’t have any other use for it.

  102. Don Rackley says:

    Nicely done! Thank you.

    After I have read through this I have 3 minor questions, perhaps you can help.
    1. In the step where you plug the Arduino into the computer, you reference a USB cable, does this come with the Arduino or do we need to buy it separately?
    2. I do not see any reference about fastening the Arduino inside the weatherproof box. Did you do that of just leave it to jostle around? Should I wrap it in anti static bubble wrap or use nylon screws through the box and standoffs?
    3. I did not see a note about how the completed assembly was fixed to the coach. I assume cable ties around the plastic box are to be used?

    Thank you for the excellent solution to an uncomfortable problem.

  103. Ken Mahler says:

    I have a question about removing or repositioning the jumpers on the Arduino Board. In photo step 1, it shows removing one jumper. Does it need to be removed before programming? In step 10, it shows removing two jumpers. Just want a little clarification on when to removed jumpers. Thanks.

  104. Tom Schleis says:

    My Arduino board came without a green plug for the VIN and GND. Has anyone else found this?

  105. Steve lamothe says:

    So can anyone confirm that this is the correct board, I’m only questioning because I do not see anywhere to “click” the extended power option on Copperhill website.

  106. Voltdoc says:

    Excellent questions thank you for bringing them up!

    1) Yes, the Arduino DUE purchased from Copperhill comes with the needed USB cable.
    2) Regarding fastening the circuit board to the housing box there are a few options, but open to ideas.
    a) The Arduino DUE circuit board comes with a plastic tray that covers the bottom of the board. This tray fits fairly tightly but could be attached to the board with small screws or double sided tape. Then that assembly could be attached to the bottom of the housing with velcro or double sided tape. Keeping in mind the board will need to be removed to get to the micro-USB connector for any future program updates.
    b) Plastic standoffs that stick to the bottom of the box and snap into a couple of the mounting holes in the Arduino board, at the moment we don’t have a recommendation for a specific product, not sure if anyone has tested this approach yet.
    3) Regarding attaching the completed assembly inside the DEF bay. This will be dependent on the specific coach. Ideas are magnets, velcro, zip ties and duct tape. In my own case I have a lot of steel nearby on my coach so I’m considering using a couple of neodymium magnets attached to the bottom of the box with 3M double sided tape. Self stick velcro will also work in most applications, or just zip tie the cable or box to something appropriate nearby.

    If you or anyone else have ideas please comment back!

  107. Archer2 says:

    Don, all good questions. Voltdoc is correct that the Copperhill Arduino Due comes with a USB cable, but not all boards do. Check the description for your board to verify.

  108. JWP says:

    Hi Ken, the jumper do not have to be removed before programing. These are termination jumpers that only have an impact when it is connected to the Chassis Can Bus network.

  109. Voltdoc says:

    Hmm, that’s not good. If you haven’t already, suggest you contact the seller for resolution. Also could you share where you bought it from?

  110. Archer2 says:

    I can’t see what you are looking at but I believe Copperhill is back ordered (and very expensive). Take a look at the alternate hardware (UNO) build instructions here
    The main difference is that this requires assembling a DB9 connector. It’s not very hard if you splice 4 small-gauge wire extensions to the main connecting cable to make assembly of the very limited space DB9 connector more manageable.
    The UNO with the Seeed CANBUS v2 performs exactly like the more expensive Copperhill DUE+CANBUS interface. You should be able to buy the hardware from your choice of sources like Amazon, DigiKey etc.

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