4L60E Transmission P0758 code

After overhaul this transmission goes to limp in and code P0758 pop up.
This happens after two days or one day or a week.P0758 is (Solenoid B Electrical).So I changed both A and B solenoids.After a couple of days limp
in again and same code.Checked in the internet for the problem,so I changed the transmission inner wiring and the post ignition switch and the same code pops up and goes to limp in.I have worked in transmissions for
years and this is the first time I see this problem.Any ideas would be nice.

My suspicion is a connection somewhere between the PCM and trans round connector. A poor connection may fool the PCM into thinking there is an open (or high resistance) solenoid connected.

You can try removing and reseating (and inspecting while disconnected) the two PCM connectors, but they are usually fairly well sealed. There may be another connector at the bulkhead, and then there is the harness (round) connector at the trans pan flange itself.

There are replacement trans wire harnesses available also, but you probably already know that having been involved in trans work.

I checked continuity from the PCM to the tranny and the readings were ok.