M939 CTIS Reprogram, Anybody Done It?

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WSm925a2

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I recently purchased a m925a2, I am troubleshooting the CTIS, and would be very interested in "renting" the device. My CTIS came with the adapter bung disconnected from the ecu and was sold to me saying (ctis not working). Since digging in, I accidentally found that the unit gives me no lights unless my headlight switch is in stop light mode or headlight mode, none of the black out modes work. I do not fully understand why the unit only works when that switch is on,however I was a little excited when I saw the freaking thing come on. Anyhow, it seems to have trouble getting to highway pressure, I have so far only gotten a solid light for "x/c". I get a flashing highway light for many minutes then the system seems to shut down and begin flashing all 5 lights. I really want to get this figured out, since I bought the truck I want all systems running the way they were meant to.
 

74M35A2

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I want to, but how do I get a $720 adapter back, and in a timely manner? Once I received it and have it operational, maybe I'll loan it out with a full value returnable deposit of $720, for a 1 week period. Still want to help members here, but not sure how to make sure it comes back. That is the only way I can think of so far. If you can find a communication adapter which is RP1210a protocol, it will work. This is the OBD standard for heavy duty trucks. I have seen them used for as low as $250 on eBay.

I don't want to turn this into a diagnostic thread, but the CTIS system likes a lot of air pressure, and is better behaved if you turn your air governor up to at least 125psi. Also if it is filling at an idle, it will intermittently pause till the pressure comes back up, this can take forever and eventually time out. Use your hand throttle to up the RPM, and once you reach 125psi, shut the truck off. Restart it and immediately depress both lower red buttons, and then the highway button, with the RPM's up. If you say your CTIS system is only powered with the light switches on, I don't know anything about that.
 
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WSm925a2

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What are the pre-programmed target pressures for the different modes, I. E. Emergency 10psi, sand 20 psi? I read them somewhere but can't find them again.

Getting the adapter back would be a concern, I took a big gamble when I bought my truck, I sent cash with a carrier who I barely knew to pick up a truck that I never saw in person, what I learned is that there are still good honest people out there...
 

74M35A2

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I think a $700 deposit will also act as a filter to separate the people who just want to play with it vs those that are serious about diagnosing their system.

The set pressures could be different per vehicle, wreckers may be higher, so it depends. I can report mine once I have it interfaced.
 

WSm925a2

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Well, I am interested... We had light up night in the several communities around where I live, pulled the truck out to the end of the driveway and the kids sat in the troop seats to watch all the firetrucks, police cars, Santa, etc.. Anyhow as soon as I fire the truck up, highway flashes on CTIS ecu, when air hit120 psi, sounded like it wanted to do a pressure check and immediately went to 5 flashing lights. It acts diffently each time though, sometimes it will keep flashing when120 psi is achieved and I hear the values clamoring as if it is attempting to raise pressure but it never seems to get to highway set point (whatever that may be) and eventually gives me 5 lights of death.
 

74M35A2

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Donor CTIS module, with cover removed. There are a total of 4 boards in here, one is LED's for the touch panel. It is non-serviceable, meaning the ribbon leads connecting them do not unplug. Contents were discarded (likely working), and CTIS control box is being used to fabricate an in-line harness of which the J-1939 (RP1210a) heavy truck OBD connector will mate to. Needed the connector of this module to do so (Amphenol model 16-26). Disconnect your CTIS module connector, plug that into this box, plug the pigtail harness from this box (not yet made) into your CTIS module, and then plug the $720 J1939 communications adapter into the 9 pin J-1939 heavy truck OBD connector. Download and install the communication adapter driver (free) onto your laptop, download and install the free Dana/Spicer CTIS diagnostic/reprogram software (free), and you should be able to monitor CTIS system functions, read system fault codes, perform manual operation of actuators, and reprogram the target tire pressure of all 5 modes.

CTIS Internals.jpg

CTIS Gutted.jpg
 

brakejay

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Looks good! Will be a nice setup!

Does the OE interface diagnostic cable have both y-connector diagnostic port and comm cable in one? Do you have any pictures of the OE setup?
 

74M35A2

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For any rally's I would attend, I will bring this with me for others to use with no "deposit", since it won't walk away. Free to diag your system, still $40 to reflash any pressure changes though. Just trying to recover the communication adapter cost with that.
 

74M35A2

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Looks good! Will be a nice setup!

Does the OE interface diagnostic cable have both y-connector diagnostic port and comm cable in one? Do you have any pictures of the OE setup?
I'm not sure. It will likely be a combination of what I am building here regardless though, just different shape and size, since it is the core objects that are required to do so.
 

74M35A2

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Special thanks to smittyjr355 for donating the CTIS module and harness to be sacrificed.
 

74M35A2

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CTIS module connector arrived today and is correct. All terminals are populated in this connector. The ones for communication with the module are not present in the truck harness connector. This connector is referred to as an Amphenol "16-26" meaning 26 pins. Below is a pic of it and the part number bag:
 

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74M35A2

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When I ordered the 9 pin heavy truck OBD diagnostic connector, it did not come with terminals or the mounting nut. Below are the part numbers for such, again, made by Amphenol:
 

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74M35A2

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CTIS interface harness parts are now all here and can be assembled. Now just waiting for the communication adapter to arrive, then we'll see what works and doesn't !!!
 

74M35A2

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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.
 
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