LMTV CTIS Question

Stellaevil · May 10, 2018

spankybear said:
Are they potted or can you service the unit?

They are all potted...

spankybear · May 10, 2018

Stellaevil said:
They are all potted...

Bummer.

I think I read that you said all lights on steady is a corrupted memory. Is the memory Non-volatile or is there a battery for the memory? The reason I am asking is that if there's a battery I would not want to get an older replacement unit. Also is there a decoder for the date on the bottom?

319cssb · May 10, 2018

spankybear said:
Bummer.

I think I read that you said all lights on steady is a corrupted memory. Is the memory Non-volatile or is there a battery for the memory? The reason I am asking is that if there's a battery I would not want to get an older replacement unit. Also is there a decoder for the date on the bottom?

If you had a C7 truck then you could flash the CTIS ECU... I wonder if I can do that with someones ECU if I connect it to my truck???
The adaptive values are stored in a RAM chip

spankybear · May 10, 2018

319cssb said:
If you had a C7 truck then you could flash the CTIS ECU... I wonder if I can do that with someones ECU if I connect it to my truck???
The adaptive values are stored in a RAM chip

If I am getting an understanding the black ECU can be flashed or at least hooked up to a computer. I have not read anything about the green ECU being able to hook up to a computer. So in theory I guess you could take a black ECU and put it in a C7 truck. I don't know if this can be done with a green ECU.

I don't know if you go through the trucks ECU on a C7 or if there is a separate diagnostic connector for the CTIS. I would take a guess that you go through the trucks ECU and it talks to the CTIS via CANBUS.

There is talk and a wire diagram for a "Y" cable to use with a computer. It would be easy to make but I don't know the interface you need with the computer. RS232? CANBUS? I don't know. I have to read this thread and a few others to get a grasp of what all going on. I know you some stuff and Dana software. Would love to see it in person... but being on the whole other side of the country and all.

319cssb · May 10, 2018

i have a green ECU in my truck and I can do this.

spankybear · May 10, 2018

319cssb said:
i have a green ECU in my truck and I can do this.

PLOT twist. Do you know the number for your ECU? I wonder if a y cable with work????

319cssb · May 10, 2018

I don't have a Y cable, I have a Dearborn III adaptor that connects to the Deutch connector by the battle kill switch.

spankybear · May 10, 2018

Trying to figure out the pin out on the ECU and I have a question. On the "Y" cable drawing it shows pins Z and M as config 1 and config 2 and pin H as swign. Looking at the TM I see that pin M config 1 is jumpered to pin H "swign". The TM shows that pin H is 24 volts form CB40. The TM doesn't show anything on pin Z config2.

So... if I am thinking on the right line... it's maybe possible to have 4 configurations with the same ECU. Say you jumper pin H to pin M like my truck you have one. More like applying 24 volts to pin M as pin H is 24 volts to say. If you jumper pin H to pin Z you may have another configuration... Jumper pin H to pin M and Z you have another configuations and lastly leave pins M and Z unconnected and you have another. 4 total configurations.

With that said and if I am correct what is the difference between the 4 configurations? Could it be pressure? Speed? Programing or what.... Or am I so far off target and have no clue?

Reading the latest spicer manual it says there is 9 different configurations between 2 pins depending if you apply voltage, ground, or leave them open.

Another questions is there a difference between the LMTV models (2.5 ton V 5 ton) when it come to tire pressure. Might have some flexibility with a selector and switching the config pins inputs.

I am using the y cable drawing here https://www.steelsoldiers.com/attachment.php?attachmentid=680452&d=1494857075

spankybear · May 10, 2018

319cssb said:
I don't have a Y cable, I have a Dearborn III adaptor that connects to the Deutch connector by the battle kill switch.

I mean a y cable for a NON c7 truck like mine.

Does the dearborn III adapter talk to the whole truck, engine, trans, ABS CTIS ect...

And got to ask what is a battle kill switch?

and do you know your ECU part number...

319cssb · May 11, 2018

My truck is a M1089a1 and the tire pressure is 81psi. The normal lmtv highway tire pressure is a lot less. I can set the tire pressure for the ECU with my DANA diagnostic software, also the over speed - speed.

spankybear · May 11, 2018

319cssb said:
My truck is a M1089a1 and the tire pressure is 81psi. The normal lmtv highway tire pressure is a lot less. I can set the tire pressure for the ECU with my DANA diagnostic software, also the over speed - speed.
View attachment 727916 View attachment 727917 View attachment 727918

It looks like your software is using SAE J1708 protocol? That would explain why pins a and N have 1708... and pins D and A might be SAE J1939? I believe J1708 uses RS485 hardware to receive... Wouldn't think it would be too hard to make an adapter. Where did you get the software? Maybe a way to bench test the ECU? There is really not much info out there on these units.

Also when you get a chance can you look at the bottom of your ECU and get the part number. It maybe 673204, 673990 or 676486.

Thanks

319cssb · May 11, 2018

It's at 204 number. But it doesn't matter what my part number is.
if you have a CTIS ECU with codes you can send it to me, I can read and erase the codes.

Suprman · May 11, 2018

Does the software allow you to make permanent changes to the pressure settings in each mode?

319cssb · May 11, 2018

It allows me to set the target tire pressure for each mode and stores it in the ECU until changed . It also lets me set the over speed speed and set it to memory

319cssb · May 11, 2018

To illustrate it I changed the tire pressure from 81.0 to 74.0 and confirmed it. The program writes it to the ECU, which then lowers the pressure. It stays programmed even if I unplug the CTIS and only changes when I change the value with the Dana diagnostic program.

in other words if you have a problem with your CTIS I can not just check the errors but can also change the tire pressure . In case you bought an ECU from a FMTV for instance

spankybear · May 11, 2018

319cssb said:
To illustrate it I changed the tire pressure from 81.0 to 74.0 and confirmed it. The program writes it to the ECU, which then lowers the pressure. It stays programmed even if I unplug the CTIS and only changes when I change the value with the Dana diagnostic program.

in other words if you have a problem with your CTIS I can not just check the errors but can also change the tire pressure . In case you bought an ECU from a FMTV for instance

Can you screen shot the "info" tab? Is there anything that talks about config or what configurations is set? There are 2 pins that set the config of the unit.

On a side note is there a wire drawing of a 5 ton FMTV? I would like to see what config pins connected and how. Also is there an M939 wiring diagram around? I haven't looked for one of them.

Stellaevil · May 16, 2018

spankybear said:
Bummer.

I think I read that you said all lights on steady is a corrupted memory. Is the memory Non-volatile or is there a battery for the memory? The reason I am asking is that if there's a battery I would not want to get an older replacement unit. Also is there a decoder for the date on the bottom?

Novram no battery.

Stellaevil · May 16, 2018

Suprman said:
Does the software allow you to make permanent changes to the pressure settings in each mode?

You can make pressure adjustments but if you go too far the system will not function correctly. Valves will not close at high tire pressures in the cold and may not deflate farther then designed.

Stellaevil · May 16, 2018

https://www.steelsoldiers.com/showt...l-Tire-Inflation-System-(CTIS)-AXTS-0015-2018

You cannot replace a 939 ECU with an FMTV ECU. Older FMTV ECUs use J1708 and newer ones use both 1708 and 1939. Changing a trucks CTIS configuration is not recommended. It could generate faults from altered performance. Currently all 4x4s from 2006 are incorrectly configured as 6x6 Wreckers, they over inflate and the higher tire pressures will not be maintained below 50 deg.F. As long as you understand these things changing the tire pressures with the DDT tool could work for some conditions.

coachgeo · May 16, 2018

Stellaevil said:
.... Changing a trucks CTIS configuration is not recommended. It could generate faults from altered performance.

What faults do you suspect would appear??

...Currently all 4x4s from 2006 are incorrectly configured as 6x6 Wreckers, they over inflate and the higher tire pressures will not be maintained below 50 deg.F.

Overinflate? Based on what? As in not the 50ish-lb the previous trucks were set for??? But then again.... maybe those were under inflated thus decision to change to the 6x6 settings? How much you suspect the pressure will drop in temps below 50 and wouldn't the ctis adjust as the tires got warm while driving?

Thanks.

LMTV CTIS Question

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