T87 8L90E TUTD tap shift what pin to enable?

[04colyZQ8]

I see that there is hardwire and TUTD enable, but what pin? I have a the resistive ladder diagram needed to make it work, from a GMPP connect and cruise 8 speed kit. But I don't have the harness or diagram for it? All it says is blunt cut, wire to trans harness. If anyone has a harness they could use a multi meter to find the pin?? GM harness kit 24284055

[radrace19]

It is pin #39 on the Chevrolet Performance transmission controller.
The OS on that TCM is 2016 CTS-V and all available transmission variables are the same except for the TUTD type is hardwired instead of Serial.

Let me know if making this switch allow TUTD to function when hardwired.
-Greg

[04colyZQ8]

Great thanks so pin 39 on the t87 controller? That's amazing how'd you find that out? I've called the dealer, gm help line, helms and searched. Everywhere. No one has wirring info for gmpp they all ask me for what vin? I seriously appreciate your help Greg!

I won't be testing for a while still got to figure out a way to get class 2 gauges, to work, cruise to work, reverse lights? And what's up with the 8speeds having a different pedal in every application except the gmpp setup? Gm service manual says for 2nd gear downshift there is a heavier spring at the bottom of the pedal? And a dedicated signal for down shift. Yet every pedal I've looked at only has the standard 6 wires? And no diagram or trouble shoots for the "8speed" pedals seem to state the wire location? Every vehicle that runs a 8l90e has a dedicated gas pedal part number for the 8speed.

[radrace19]

I ordered the harness in the day it was available to look at it.
I didn't make note of any other wires in that harness since TUTD was all I was concerned with.

I've never looked at the pedal difference in the parts catalog.

-Greg

[04colyZQ8]

That's pretty cool! Did you sell the harness after? So I wasn't the only one that noticed the connect and cruise had tutd

What to poeple typically do for cruise with the gmpp kits?

[radrace19]

Yes I sold the harness shortly after I received it. I seem to remember it going to Ford R&D or something like that.
So your are correct in thinking your were not the only one interested.

Most are using the Dakota Digital cruse control units with the Chevrolet Performance Kits.

I was mistaken. It is pin 39 on the trans controller that GM uses for TUTD functions.
See this 2016 CTS-V schematic
CTS-V TUTD.jpg

2017 CTS-V schematic
2017 CTS-V TUTD.jpg

[04colyZQ8]

What year ctsv is that? Looks like it still uses the bcm??

[radrace19]

2016 & 2017 V is the schematic, but 2016 is the OS and TCM CPP uses. GM connects the TUTD to pin 39 on the TCM via 24284057 harness and has the software switched to hardwired instead of serial.
-Greg

Edit added 2016 and 2017 schematics

[radrace19]

Here this might help you out some. I dug it up for everyone interested.
CPP Harness schematic
Pin 39 was correct
-Greg