GM TCCM Plugs & Wiring

Wiring diagrams and questions
Sbornoe
Posts: 4
Joined: Sun Jun 22, 2025 12:22 pm
cars: Silverado 03, Hummer H1

Re: GM TCCM Plugs & Wiring

Post by Sbornoe »

More pictures, having problems uploading. Maybe because I am literally near the North Pole, North of Norway😅
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Sbornoe
Posts: 4
Joined: Sun Jun 22, 2025 12:22 pm
cars: Silverado 03, Hummer H1

Re: GM TCCM Plugs & Wiring

Post by Sbornoe »

Last one for now, maybe I have more relevant info for you. I have been working on this for many years now, now and then. So most likely I’ll have more info if you need, or we can share info. I forgot to mention, I am going to use a LB7/Allison 1000 transmission in front of my MP1626xhd and they don’t speak canbus language like the tccm from LML does, as my tcm and ecm only needs ground signal from tccm to understand 4low and reduce accordingly. And other way around, the NP263xhd (stock 2003) tccm request volt signal from neural before willingly allowing 4low. So I have to make analog signal to canbus language one way and canbus to analog the other way😳 or maybe I am wrong and it all works when I get the new tccm from the 2016 LML…
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Tre-Cool
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Joined: Tue Oct 16, 2012 2:17 am
cars: VY SS UTE, VX Drag Car
Location: Perth

Re: GM TCCM Plugs & Wiring

Post by Tre-Cool »

I did manage to order in a bunch of connectors for this project a couple of months back, but.. haven't dont anything with it yet.

Also got various transfer case adapters for the different gearbox's & transfer cases i have.
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Sbornoe
Posts: 4
Joined: Sun Jun 22, 2025 12:22 pm
cars: Silverado 03, Hummer H1

Re: GM TCCM Plugs & Wiring

Post by Sbornoe »

Tre-Cool wrote: Sun Apr 05, 2026 3:16 pm I did manage to order in a bunch of connectors for this project a couple of months back, but.. haven't dont anything with it yet.

Also got various transfer case adapters for the different gearbox's & transfer cases i have.
I also have a full wire harness from fuse box all the way through the switch to t-case from LML or similar. Little bit hacked but worked with tccm with only power and ground. Main issue is the canbus setup, for tccm to think its connected to tcm,ecm and or bcm. You have any ideas about that?
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Tre-Cool
Posts: 533
Joined: Tue Oct 16, 2012 2:17 am
cars: VY SS UTE, VX Drag Car
Location: Perth

Re: GM TCCM Plugs & Wiring

Post by Tre-Cool »

from what i have gathered and can see in the various can id broadcasts in the ecu/tcm it makes sense that the tccm is listening for engine rpm, speed, pedal position & gear state. which would be how it locks out a shift into 4 low without coming to a stop & placing into neutral.

I can probably upload some can logs from my Colorado & switching from 2wd to 4wd etc if that would help. Can point out what the id's are for.
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