M939 CTIS Reprogram, Anybody Done It?

[therooster2001]

I will retry the j1708 pins when I grab my 422 ECU, but I have been down this road. 74m is using a combox. I am just hitting it with an Rs485 connection and no terminators, I have no com box. Explain the "synced" part. If it send something, so can I.

 

[firefinder]

Stellaevil,

You mentioned "The original green ECU has no com capability and all the unused pins are internally traced to ground and could damage you com box."

Do you have a part number for the ECU that may damage the com box? Hope to stay away from those part numbers!

Thanks!!

 

[Stellaevil]

I will retry the j1708 pins when I grab my 422 ECU, but I have been down this road. 74m is using a combox. I am just hitting it with an Rs485 connection and no terminators, I have no com box. Explain the "synced" part. If it send something, so can I.

The DDT Software will send a request to the ECU, The ECU will not broadcast anything until it sees this request. So if you have a combox connected with a bus active light, and nothing else on the bus the light will not show traffic until you start the DDT software then you will see the traffic light from your computer trying to communicate with the CTIS. If it does not receive a response in a few seconds it will time out.

 

[therooster2001]

The DDT Software will send a request to the ECU, The ECU will not broadcast anything until it sees this request. So if you have a combox connected with a bus active light, and nothing else on the bus the light will not show traffic until you start the DDT software then you will see the traffic light from your computer trying to communicate with the CTIS. If it does not receive a response in a few seconds it will time out.

I am trying to create a monitoring program, so no combox. Any way to recreate the DDT request via program? That's the key to my project.

 

[74M35A2]

The DDT Software will send a request to the ECU, The ECU will not broadcast anything until it sees this request. So if you have a combox connected with a bus active light, and nothing else on the bus the light will not show traffic until you start the DDT software then you will see the traffic light from your computer trying to communicate with the CTIS. If it does not receive a response in a few seconds it will time out.

Just like my marriage.

 

[Stellaevil]

I am trying to create a monitoring program, so no combox. Any way to recreate the DDT request via program? That's the key to my project.

Yes, you can send the request message to the ECU and decode the response. The response will contain the current mode and fault codes active and historical.

 

[therooster2001]

Is there any special J1587 command to initiate it? MID or PID? I guess I could sniff it out if I had the cable connection and program that 74M does. Any docs on those things?

 

[Stellaevil]

Is there any special J1587 command to initiate it? MID or PID? I guess I could sniff it out if I had the cable connection and program that 74M does. Any docs on those things?

Here is enough to be dangerous. See how this goes, I may be able to send you the full spec.
Command: ECUs on Data Link
Display: MID & SAE J1587 MID Description for user selection
Global Request: 172 / 000 / 243 / CS
Specific Request: 172 / 128 / 243 / MID / CS
Response: MID/243/n/MID/b / b …. / CS
Reference: MID 166 = Tires, Power Unit Byte “n” is the number of bytes to follow.

Bytes “b” above are not used.
Note: Some earlier systems do not respond to the Global Request. After responses to the Global
Request, if MID 166 not found on the link, use the Specific Request to detect any remaining
systems.

Command: System Type
Request: 172 / 254 / MID / 000 / 121 / CS
Response: MID/254/172/121/a/CS
Reference: The system type, 1 byte in length shown above as “a”, will have one of the following values:

1=CTIS, 3=MTVR, 4=FMTVA1.

Determine system in this order:
1.) Request Component ID (PID 243), if no response then no controller is connected.
2.) If the part number does not match any of the above, then request the system type (PID 121).

Command: Vehicle Configuration
Request: 172 / 254 / MID / 000 / 209 / CS
Response: MID/254/172/209/x/a/b/c/d/e/f/g/h/i/j/k/l/m/n/o/CS
Reference: “x” is the number of bytes following (may vary in length depending on system)

“a” is the harness configuration in decimal format, range 0-255
“b” is the maximum number of channels (electrically connected), decimal format, range 1-4

“h” is a bit-mapped byte as follows:
bits 7,6,5 – not used
bit 4 – FS: Freescale 9S12XE based ECU (0 = not used, 1 = used)
bit 3 – PTM: pressure target matrix method (0 = not used, 1 = used)
bit 2 – atm press PID (0 = not available, 1 = available)
bit 1 – target limit PID (0 = not available, 1 = available)
bit 0 – deflate style (0 = pressure based, 1 = vacuum based)

“k” total_group number of tire groups, front to rear, range 1-4
“l” total_terrain, number of terrain selections, range 3-7
“m” total_load, number of load settings, range 1-6
“n” terrain_pattern, reference to terrain text as follows:

n=10 n=11 n=12
0 = Emergency 0 = Emergency 0 = Emergency
1 = Mud/Sand/Snow 1 = Mud/Sand/Snow 1 = Off Highway
2 = Cross Country 2 = Cross Country 2 = Highway
3 = Highway 3 = Highway
4 = Air Transport

 

[therooster2001]

Perfect, I have some coding to do, Thank you!

 

[The HUlk]

I knew somebody would eventually get some documentation on this, nice.

 

[dronsen]

Is this project dead? I was rooting for you guys!

 

[74M35A2]

It's not dead. I still need to add termination resistors and try communication again. Apology for the long delay.

 

[therooster2001]

Yeah, get on it alternator boy.

I need to get on the sending the enable code. I haven't even driven the truck for two months. Work is killing me.


Sent from my iPad using Tapatalk

 

[74M35A2]

You know, there is another name for a rooster...

 

[therooster2001]

A chicken?


Sent from my iPad using Tapatalk

 

[74M35A2]

Not really.

 

[Jbulach]

I put the newer ECU from my parts truck on todayit runs the updated 70PSI on Hwy, all other pressures stayed the same. It also has the blackout function as well, where the lights only come on when the normal lights are switched on.

If I can find a good deal on a 90psi transducer, I may try adding it, with switch and tee to my existing transducer, to see if I can toggle between 70 and 90psi.

I would like to also see what happens when mixing the old and new components?

 

[Smckerigan]

I belive there is a member named Superman that has them for sale..

 

[CARMAN]

Subscribed!

 

[mzak88]

Is this thread dead now?