Throw that harness away and just swap 2 pins. Ive had nothing but trouble out of those adapter harnesss.

 

Did you follow the diagnostic i posted?

 

I attempted to, I don't fully grasp everything outlined in it. Automotive wiring isn't my strongest skill. I feel like it has to be wiring related at this point.

 

I need to look for that diagram again on which pins to swap. At this point it's my best option I think.

 

Just swap S and U at the Trans 20 pin connector.
And that code is a wiring/solenoid code.
If you can put ground to pin S and the TCC noid doesnt click, then you have a internal wiring issue or a bad solenoid.

 

Thank you, that makes more sense to me.

This was the diagram I had saved:

https://lt1swap.com/4l60e_4l80e_harness.htm

 

I am forever in your debt. Got rid the harness, moved pins in factory connector. Works like it should. Im slipping in my old age, I am kind of pissed at myself for not verifying that all the pin locations were correct. Lesson learned.

For anyone else following along, or who might stumble across this thread in the future...

Cliff notes: that cheap adapter harness was pinned incorrectly.

 

And now you understand why i dont trust that junk.
Its much easier to just swap those 2 pins than it is to use the adapter.

 

I'm also a believer of simply swapping the wiring/pins. The wiring for the additional speed sensor is basically already there, might as well take advantage of it. Costs nothing but a bit of time and electrical tape.

'm glad you figured it out. Great job! 👏🙏

 

It 100% is. When I didn't know any better, I used a similar kit from Speartech on my 2001. It never gave me trouble. However it wasn't cheap, and now 9+ years later it's almost double what I paid. I have enough junk harnesses I keep around for connectors and such, I literally could have grabbed a speed sensor plug and the two wires with the pins and added it to my existing harness. Then swapped pins in the connector. That would have been free.99

Live and learn...

THIS right here is why I prefer the forums. If I had asked on FB, I would have gotten 50+ replies telling me to hit it with my purse.