M939 CTIS Reprogram, Anybody Done It?

[Amosclifford1978]

There is. But I believe they are rare/expensive/both. Suprman (SS member) chased it down pretty good and found one was made for a field update kit. He also says the CTIS diagnostic kit for the xMTV series trucks may use the same piece. But, I don't believe he ever acquired one. Since I have not seen any other posts about people running the diagnostic program or reflashing their target tire pressures, I simply assumed they were hard to come by.

For me, I like making stuff like this. It forces you to dig deep and understand each and every terminal and purpose, and the satiafaction of having the laptop screen say "Connected" when first turning it on is amazingly rewarding having built it myself. Or, I'm just easy to impress. Even the CTIS tech support guy at Dana was wrong in his saying there is a diagnostic port in the truck to connect to. Ummm, no there is not, and I confirmed that when I did a pin-by-pin shakedown of the truck side module connector and found the exact pins missing for both bus communication lines.

There are 2 parts needed to communicate with the CTIS modules on any M939A2 vehicle: An interface harness which taps into the communication pins in the CTIS module connector (not present in truck side wiring connector), and a 2 channel CAN module communication adapter which deciphers the 2 way language utilized by the CTIS module. Then of course the (free) Dana diagnostic software on your laptop.

I know this is an old thread but did this ever end up working? i would love to fix my ctis

 

[DeMilitarized]

I know this is an old thread but did this ever end up working? i would love to fix my ctis

Send me a PM and I can help diag.

 

[KN6KXR]

Got any pics of your harness? Thinking I can just use the factory pigtail on the truck and solder the diagnostic wires onto the back of the pins or if the pins are missing install the missing pins/wires.

It's in my shop someplace in it's project box.... It's really basic you have to break out power and comms from the plug. Problem is the plug is a solder cup style and the wires are quite small. I highly doubt you will be able to solder them into the factory plug simply because there's no space. If you had the harness mostly out of the truck, let's say you could flop it out over the passenger seat, then maybe you could set up there and get it done. You really have to methodically follow the Dana CTIS document for the pins you need to break out. For the few that do this every day I'm sure it's a snap but for the rest of us I suggest taking your time. Especially if you want it done right.

I'll actually be doing another one for my M1078A0. Turns out the pinout is different for that vehicle even though the connectors are the same. So be advised if one were to try to use an FMTV module in a M939 series you would need to redo the connector but it would work. Maybe make an adapter connector? The next one I make will be much longer the first one has me cramped with the laptop and Dearborn adapter I made it only about 8" long. Something maybe 18" would be better. For such a big truck there sure isn't a lot of space sometimes.....

I might be doing this soon. My right collarbone decided to come apart again so I'm getting it plated again (permanently this time) to prevent rotator cuff damage later. I could use a bench project to keep me busy and from lifting with my arm. It would be nice to get the M1078 CTIS talking. It won't be fixed I've got hub seals to do and that won't be happening with one arm. Familiar story the M936A2 had 4/6 bad seals when I got it. Also I have a bleed down and failure to fill from sand mode (but not from Xcntry or Hwy) on that truck at the moment. I suspect some wheel valves are going bad I'll need to renew those.

I love my CTIS. I actually use it quite a bit. It's work though.....