Transmission will not go on reverse only first gear, codes P0891, P1775, P0731, P0732, P0841and P0846

1. When I put the red lead on the 2/4 pressure switch pin1 and the black lead on the return wire, look at the readings on this video.

When I put the red lead on the o/d pressure switch pin3 and the black lead on the return wire, look at the readings on this video.

What can you say about this situation? Because I said let me do the test first before proceeding to body valve if it pass the test?

Which one supposed to be 12volts, Is it the pin 1, 2and3?
Note: the procedure says:
Turn ignition to lock position
Disconnect PCm harness connector
Disconnect solenoid/pressure switch connector
Remove transmission control relay
Connect a jumper wire between B+ and control relay output circuit,
Turn ignition on, engine not running
Measure the voltage of 2-4 pressure switch circuit.
Is the voltage above 0.5volts?
If Yes: repair 2-4 pressure circuit for short to voltage
If No:Go to next

Check and see if any of the wires have 12 volts: the return wire pin4 has 12 volts.
How many volts does the 3 sensor wire supposed to have?

Red lead into pin4 and black lead to pin 1. Tell me the voltage.

That indicates an open circuit on the 2-4 sense wire. That is ghost voltage as it is not constant voltage. This indicates an open circuit. Thank you very much. It is the same way on O/D sense wire, except L/R sense wire(Red lead into pin4 and black lead to pin2) reads 0.4 to 0.5volts and this could be the reason why only first gear works on the vehicle. So I need to uncover the wire harness and repair 2-4 and O/D sense wire?

Good evening! Correct. There is either a broken worn or corrosion in the harness: I disconnected PCM connector and Solenoid/Pressure Switch Assembly, I check resistance on each pin. There was continuity and I removed transmission control relay and used jumper wire to connect fused B+ and transmission control relay output, as I put the red lead on pin1 and black lead on pin4 to measure voltage, it reads 10.16 volts on all the pin1(2-4 pressure switch) =10.16volts, pin2(L/R)=10.16 volts and pin3(O/D)=10.16 volts, so I guess the 3-sensor wires are short to voltage. Am I correct?

Alright, thank you. Tomorrow I will change the wires and still run the vehicle, whatever result I get, I will let you know.

Hello! Good evening sir!
I am getting more confused about this situation. I remove the feedwire from the C3(5) on the IPM and Pin4 of solenoid connector and put another wire, I connect the jumper wire between B+ and the return wire in the IPM. I put red lead on the Pin1 and black lead on pin4, it reads 1.9volts, the pin2 and pin3 readings are between 1.9. To 2. Volts. I am totally confused now. Please help.

How do I measure resistance between ground and the 2/4 pressure switch sense circuit?

Is it not better that I replace ECM and check since I have changed 3-different solenoid packs and it was still doing the same thing?

It is not a component problem. It is a wiring harness issue: yes I have now agree with you because I disconnected the transmission control module connector c4 and I set my multimeter on resistance mode, I place the red lead on c4(38)(28)(19) transmission control relay output feedwire(y/or) and black lead on c4(13)(14) transmission ground wire(bk/lg), the multimeter began to beep showing that the feedwire and ground are shorted together somewhere in the harness.