Walkernk

I have a 77 Datsun 280z with a 2005 LQ4 (stock pistons, 228/232 112LSA cam, trunnion upgrade, PRC heads...), a 2003 4L60e that has been rebuilt (upgraded with all new everything molded pistons, BW internals and clutches...)

about a month ago I was driving to work and all the sudden it popped out of OD and shifted into 3rd. When i got home I ran the scanner and got the code P0785 and P0706. Based on searching and reading I pulled the pan and replaced the wiring harness, 1-2 valve, 2-3 valve and the 3-2 valve. After putting everything back together, the P0706 code has gone away but I am still having the P0785 code.

I figured it might be wiring in between the ECU and the transmission I pulled the wiring harness and tested it via HP tuners. Below is the results of my testing.

Transmission pin A > 1-2 shift solenoid > Pin A is grounded when I activate the 2-3 solenoid in HP Tuners
Transmission pin B > 2-3 Shift solenoid > Pin B is grounded when I turn the 1-2 solenoid off in HP Tuners
Transmission pin S > 3-2 Shift solenoid > Pin S is grounded when I activate the 3-2 Solenoid in HP Tuners

Based on these findings I believe the ECU to be working fine and the wiring between the ECU and the transmission to be fine (my wiring is wrapped in abrasion resistant sheathing and looks to be in perfect condition).

My only thought is the replacement harness I put in or the replacement 3-2 valve is faulty. I am not sure if there is anything else that could cause the 3-2 P0785 issue (was thinking last night it could just have needed a new tune flashed...)

If you have any other ideas as to what else to do please let me know.

FranksCustomTrans

This is an electrical code for the 3-2 .It can be the harness, harness plugs, wiring , pcm, or low battery/ charging voltage or Ground and of course the Solenoid itself. But is an electrical code, You a have changed the 3-2 and internal harness, So a few possibilities exist .
1- Wrong 3-2 solenoid from 93 through 95 aftermarket harnesses will accommodate this.
2- Harness issue trans plug to PCM or wiring
3-PCM itself.
4-Low voltage at PIN E and or poor ground for body or PCM (This is what I would look into first based on the things you have done thus far unless you think you may have gotten hold of an early style solenoid )