95' t444e vpm wiring

skylerm · 01-03-2025, 12:21 PM

I got my hands on a 1995 t444e to swap in but it did not come with VPM or ECU, I ordered them online and they are arriving soon, my harness has the ECU connector, but it looks like I'm going to need to create a plug for the VPM does anyone have the pinout for it, as well as what wires I need to run to the j1708 port to run diagnostics/ change defaults. Any help would be much appreciated,

nikitis · 01-07-2025, 06:17 AM

The T444E eges-125 manual has the wiring diagram in it. It's is crude but should give you an idea of The pins layout. To the vpm it's basically two DCL LINES and two ACL lines. For data in and out, and they are twisted pairs and require under 2.0 ohms of resistance on them to work right. Then there is ground and power lines for the VPM

So I would ask why your VPM harness is missing? Seems highly unlikely it would be removed. VPM's are removed to use in other bus projects like my bus. My BUS took 4 VPMs out of 4 buses because 3 of them didn't work. The 4th one did. But the wiring shouldn't be removed and you should be able to just plug in the ECM and VPM to existing harnesses. I can send pics later.

Additionally once all of the wiring and hardware is plugged in, you'll need to take to dealership to flash via NavCal to program in the VIN and specifications and get the initial calibrations. After that service Maxx with Godmode can edit them to enable or disable features but you gotta have that initial sync and upgrade to put both the ECM/VPM within a software version range or they won't talk to each other as protocols changed in certain versions so paying the dealer is necessary for the initial program unless you just happen to have ripped an ECM/VPM together from another bus and they are already compatible software wise.

cadillackid · 01-07-2025, 08:29 AM

if i were doing a T444E swap into a custom project, I would totally *NOT* do a 3 box..
I would getthe setup for a single box, and then buy an Orion buiolt to work with the AA, AB (or if lucky enough the AC ) injectors...

nikitis · 01-07-2025, 09:24 PM

Quote:

Originally Posted by cadillackid

if i were doing a T444E swap into a custom project, I would totally *NOT* do a 3 box..
I would getthe setup for a single box, and then buy an Orion buiolt to work with the AA, AB (or if lucky enough the AC ) injectors...

Agree except it sounds like hes already got the 3box harness. It may be worth the price of a 1 box harness though. Also the 1box setup would have J1939 already, and could save you money with being able to have better options for transmission upgrades now and down the road.

One thing I dislike about the 1box and its a small thing, is the location. 2 of the 3box computers are in-dash. The IDM is up top on the 3box where all the engine heat is, but is at least somewhat cooled via the heatsink that is the firewall.

The 1box computer placement next to the hot engine seems like a terrible design choice. I dont know the history of why they made those choices but i know international understood in the 3box era to take what they could computer wise and stuff it behind the dash, so if they knew in the prior generation to do that then why did they cut corners with the 1box?

The 3box common failure was the IDM usually.

cadillackid · 01-08-2025, 07:32 AM

Quote:

Originally Posted by nikitis

Agree except it sounds like hes already got the 3box harness. It may be worth the price of a 1 box harness though. Also the 1box setup would have J1939 already, and could save you money with being able to have better options for transmission upgrades now and down the road.

One thing I dislike about the 1box and its a small thing, is the location. 2 of the 3box computers are in-dash. The IDM is up top on the 3box where all the engine heat is, but is at least somewhat cooled via the heatsink that is the firewall.

The 1box computer placement next to the hot engine seems like a terrible design choice. I dont know the history of why they made those choices but i know international understood in the 3box era to take what they could computer wise and stuff it behind the dash, so if they knew in the prior generation to do that then why did they cut corners with the 1box?

The 3box common failure was the IDM usually.

well the 1 box design definitely had the issue of a bad IDM not being field replaceable.. it was enough of an issue that the VT365 and DT466E EGR went back to a 2 box design (for PCM control)..the ECM and IDM were separated... of course a BCM was added into the mix for peripheral control ..
if not taken care of those special connectors on the singble box could get damaged too.. following the torque specs is pretty crucial.. this why they have a plastic thumbwheel .. designed to strip out on its back side if you over torque the connector bolts..

skylerm · 01-10-2025, 05:54 PM

Yes it is going into a custom project, I wonder if there is a way to bypass needing to get the boxes programmed together to communicate, I'm going to try and monkey together some sort of j1708 port to connect my nexiq USB link, give the computers some 12v and start tinkering on it, gonna keep looking for ways to flash the software myself. thanks for the advise fellas.

cadillackid · 01-10-2025, 06:31 PM

Quote:

Originally Posted by skylerm

Yes it is going into a custom project, I wonder if there is a way to bypass needing to get the boxes programmed together to communicate, I'm going to try and monkey together some sort of j1708 port to connect my nexiq USB link, give the computers some 12v and start tinkering on it, gonna keep looking for ways to flash the software myself. thanks for the advise fellas.

you can try just connecting them all up with their harnesses.. power and ground lines.. (there are multiples) are important...

the god mode servicemaxx.. somepne prob has the current link can program things such as horsepower rating but cant program the base cal.. the base calibrations have to use NavKal wit han active subscription...

of course without a real engine you'll set a zillion codes... the important ones would be related to communications between IDM / VPM / ECM.. upper 500s and 600s i think in the code numbers..

if you dont get any comms codes then chances are you can just put the thing together and run it..

skylerm · 01-11-2025, 12:52 PM

Quote:

Originally Posted by cadillackid

you can try just connecting them all up with their harnesses.. power and ground lines.. (there are multiples) are important...

the god mode servicemaxx.. somepne prob has the current link can program things such as horsepower rating but cant program the base cal.. the base calibrations have to use NavKal wit han active subscription...

of course without a real engine you'll set a zillion codes... the important ones would be related to communications between IDM / VPM / ECM.. upper 500s and 600s i think in the code numbers..

if you dont get any comms codes then chances are you can just put the thing together and run it..

See.. that's that blind optimism I like, Ill keep yall updated if it works out

skylerm · 01-11-2025, 01:45 PM

Also, let me know what you guys think about the Hydra Chip, is it possible this could make them happy to work together

cadillackid · 01-11-2025, 06:24 PM

the hydra chip wont make the VPM talk to the system.. if I remember right the hydra chip alters the calibrations that are in the ECM.. youd have to talk to powerhungry to see what all the hydra does but I think oyu need your VPM to communicate correctly for various functions to work like your speedometer and some of your gauges..

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