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M939 CTIS Reprogram, Anybody Done It?

74M35A2

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That should work. Remember it requires air pressure to deflate also. Air pressure is not kept on the line continuously, only to inflate or deflate.
 
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I don't know if this is the same setup? I ran across this a year ago on a post. View attachment 653299
Yup that's what I built. Just my T is in a different configuration but works the same either way. You can air up or air down with ease just set regulator to desired pressure open the feed it'll air up or down to the pressure you have set and then shut off the feed and open the dump and it releases the pressure from the system so it's not constantly pressurized.
 

Csm Davis

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Yup that's what I built. Just my T is in a different configuration but works the same either way. You can air up or air down with ease just set regulator to desired pressure open the feed it'll air up or down to the pressure you have set and then shut off the feed and open the dump and it releases the pressure from the system so it's not constantly pressurized.
So do you have to start at the same psi that is in the tires to deflate after the wheel valves open? Adamsoffroadprerformance if you have a thread on the manual setup would you post a link here or start one so we don't clog up their cpu thread.

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Andyrv6av8r

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So do you have to start at the same psi that is in the tires to deflate after the wheel valves open?

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I don't think so. You may have to go a little higher to get the wheel valves to open first, then hit the dump valve while the fill is closed.
 
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ramdough

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So do you have to start at the same psi that is in the tires to deflate after the wheel valves open? Adamsoffroadprerformance if you have a thread on the manual setup would you post a link here or start one so we don't clog up their cpu thread.

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Yes please!


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therooster2001

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well, I ordered the wrong ends (exactly opposite from what I needed), so returned and ordered the right ones. The male / female connector also has male / female pins that lock into it. Geez. I have also misplaced my arduino(s), and just found them, so I can test out the Eaton 1708 stuff now. Sigh.. Slow progress. I have a feeling once my winter travel drama is over, I will be able to get this soldered, hooked up to the right ECU and displayed on my backup monitor. Again, not a dead project, just slow. And for those who have NO idea what I'm doing as this thread went a bit sideways. I am building a display for ECU's. My hunch is a 50% chance that my actual ECU Dana model number will give me diagnostics. 25% chance the Eaton will give them over 1708 protocols. I REALLY hope this works on the Eatons, as I think most M939's use the old Eatons, at least that was my experience in the salvage yard. 99% Eaton. I know this is literally 1 year in the waiting. I think the original ability to reprogram the ECU's is not a dead idea, as if I can get this working, then we're there too. I think the resistors are the key to getting this done. I plan on going up to see the truck tomorrow, but probably just to warm it up, start it and see if I don't have a air in the fuel leak I have to deal with.
 

Suprman

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I was speaking with one of the mil mechanics I know. She said she was able to access the ctis controller thru the main diag port on lmtv A1 with the dana software on the msd. It may only be on the c7 trucks with data bus though.
 

74M35A2

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I was speaking with one of the mil mechanics I know. She said she was able to access the ctis controller thru the main diag port on lmtv A1 with the dana software on the msd. It may only be on the c7 trucks with data bus though.
Same as the Eaton CTIS phone tech told me. I believe an LMTV CTIS controller could be used on an M939, but button layoit/orientation is flipped if you are mounting it same as original. I have not tried to communicate with an xMTV CTIS module yet.
 

Suprman

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Unfortunately the m939a2 ctis is 24 volt and the lmtv/mrap trucks are 12 volt. They are not interchangeable. You might be able to power the m939a2 ecu separately on a lmtv and program it that way.
 

therooster2001

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Sorry peeps, I am back. Work and travel killed this project for a bit. The fuel / air leak was a non issue luckily.

I need to get going on the soldering, I have all the right pieces. Motivation is there, but my time dwindled with multiple jobs / businesses. I hope no one is pinning their livelihood on this. I'll get this moving.
 

therooster2001

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Ok, I soldered up half the connections, isolated the 1708 and 1939 connections, now onto the other side. Also found an older Dana manual that had just 1708, so that at least is encouraging. After the solder up, I have to redo my Arduinos. Probably won't get to the truck to test this weekend, but I'll be ready by tomorrow, so maybe a quick run up there next week to test a couple of things.

What's the consensus on manufacturers of your CTIS ECU for 939's?
 
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