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M939 CTIS Reprogram, Anybody Done It?

99nouns

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Ocala, FL
OK, I soldered up the 1708 and 1939 connections to wires. Now I need to figure out which protocol and then see what data it gives. The unknown here is that I used a CTIS controller that I didn't check on the truck. This was the one I took apart before. Let's hope that it still works!

View attachment 635248View attachment 635246View attachment 635245
How did you figure out what ports to use? Or are you just picking random pins to see what data you can get?
 

therooster2001

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Colorado
The ports are all mapped out in the DANA CTIS "TM".

The orange circle is what I wired today, both J1708 and J1939. The red arrow is pretty much what we are not happy with. The wiring harness on the truck side didn't have any of the diagnostic ports wired, so we are doing it.

wiringdiagram.jpg

You can see "a" and "N" are the J1708 and the "A" and "D" pins are the J1939. The ports below are the wiring harness and the component connector. My earlier pict is inside the ECU, so it pretty much just like the wiring harness. Remains to be seen if the ports are actually active, which one, and what information it will give out. Hoping for J1939, but J1708 is still out there.

connector.jpg

I did find a DIGI wireless J1708 wifi adaptor that plugs into the Deutch 9-pin connector that would be cool to do, had our trucks have it connected, and integrated into the other systems. I think there is more that our trucks can tell us than we think. After the CTIS thing, I might check into the truck diagnostic port to see if our engines are telling us anything.
 
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firefinder

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Macon,MO
therooster2001,

Looks like progress!

I have no experience with CTIS internal workings, but I did assist with some of the troubleshooting on early autopilot interfacing with the NMEA2000 protocol (a CANbus derivative). Don't know that I can assist much, but glad to do what I can. I like the idea of having a system we can modify as we need.

Keep us posted!
 

therooster2001

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I can send several known working ones.
I may take you up on that. I hope that we can find the common thread between all ECU's, although I bet there will be an oddball one. I am not sure we want to modify the ECU's. Once we find out the wiring, I want to head down the direction 74M35A2 was going with a harness, and then we can route the correct pins to the processor, then either jack it out to a 9-pin and video or just the video. We'll see. Once proven, I want to test most of the PN's, and then on different trucks. I know we have a lot of M939's, LMTV's and a request for M35A3's. Thanks for volunteering hardware!
 

therooster2001

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therooster2001,

Looks like progress!

I have no experience with CTIS internal workings, but I did assist with some of the troubleshooting on early autopilot interfacing with the NMEA2000 protocol (a CANbus derivative). Don't know that I can assist much, but glad to do what I can. I like the idea of having a system we can modify as we need.

Keep us posted!


I bet you'll be helpful, stay tuned to this or the new thread (which I'm not sure will happen, unless I get a little better with my docs, which I NEED to do). Thanks!
 

therooster2001

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Well, the ECU works on the truck. Still need to figure out which protocol, 1798 or 1939, so need to get some resistors, and get the arduino code working to read it, and then try either one. Felt like getting truck stuff done instead of coding, so maybe next week.

Btw, highway was flashing but I kept missing the light.

IMG_2181.jpg
 

therooster2001

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Ok peeps, I have two paths to figure this out. I got in a CAN board for an arduino, but doesn't have too many docs. It's probably just the J1939 wires, although I thought I figured out a way for that board to do J1708. I was at a conference over the weekend where someone presented a talk on hacking heavy trucks, and hooked up with him an received a very cool board that should interpret the protocols as well. So the next step is to build up my boards connect up and see if I get anything. If o get anything exciting I swear I will start a new, more informative thread to give you guys the docs on all this...and Picts...
 

therooster2001

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I still think it's simpler to just replace the ECU entirely.
I know you do, but this is still valuable for diagnostics and other people's visualization of what the stock controller is doing. I will probably learn something you need, so hang in there, I know you are going a different direction. Unless you know how the rest of the components talk you'll still need to do that research (air pressure, speed control, etc) so this still has value. I've spent only about 4 hours so far on this. $25 in parts. This also has a lead on to the truck diagnostics itself, so probably no wasted effort, most heavy truck diagnostics are $700 to start. If I can do it in $50, I still think it's a win.
 

therooster2001

Active member
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Location
Colorado
So I just attempted this again, and got no receive data. I think it was giving me false data before. I tried to make heads or tails out of the data, it looked wrong. I did redo my code twice, so maybe I got lucky before, but I have to check something else. I did see an interesting thing on the DANA manual. On the M939 section it does reference a specific model (theirs), which I have on my truck, just not the Eaton one I wired.

CTISDanaManual.jpg

Spicer.jpg

I am wondering if we can get this info, just out of the later controllers. 74M, you willing to lend me your harness? I am not going to use the truck adaptor, probably just the pins to my arduino. This will enable me to test my other ECU without cracking it open. I'm still not giving up on my Eaton controller though. I am going to scope it to see if ANYTHING is actually coming out of the pins (1939 or 1708..)
 

Suprman

Well-known member
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Stratford/Connecticut
Hard fault. If 5 lights when you start the truck and no flashing at all then its a controller, valve body or harness. Easiest way to troubleshoot is finding a known good controller and swapping.
 
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