GMPP LS3 with T42

Trying to troubleshoot why a GMPP LS3 and T42 cannot communicate properly to make the trans shift. I cannot read the trans cal from OB2 port. Assume I'll need to use the cord and GM software to make updates.

What should I be checking? Assume the MPH and RPM are going into the ECM.

Here is a download I found about it.

https://www.chevrolet.com/content/da...r-10302410.pdf

can you confirm the can wiring goes from obdi connector to t42 ecu, then from t42 ecu to engine controller. because if it's wired firect from obdi to engine ecu then it wont work.

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Originally Posted by LastCall

Trying to troubleshoot why a GMPP LS3 and T42 cannot communicate properly to make the trans shift. I cannot read the trans cal from OB2 port. Assume I'll need to use the cord and GM software to make updates.

What should I be checking? Assume the MPH and RPM are going into the ECM.

Here is a download I found about it.

https://www.chevrolet.com/content/da...r-10302410.pdf

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Are you running a T42 or the TC2 controller in the instructions?

Quote:

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Originally Posted by Tre-Cool

can you confirm the can wiring goes from obdi connector to t42 ecu, then from t42 ecu to engine controller. because if it's wired firect from obdi to engine ecu then it wont work.

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This is the TC2 kit, so I think the wiring may be a little bit different and that is why I cannot access any info from the OB2 port.

Quote:

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Originally Posted by gmh308

Are you running a T42 or the TC2 controller in the instructions?

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It is the TC-2, I made mistake in typing the T42.

We are going to check the VSS sensor, as everything else is plug and play.

Thought I would report back - it was the ECM, it was not communicating with the TCM properly. Changed the ECM, and all works perfectly.

Thanks for posting back, glad you got it sorted.