P0753 Hnda Civic 96- solenoid and d4 flashes

Question

I change the upper shift solenoid cause the mechanic told me it was the one, to fix, now I checked the resistance, the wires, the ecu, the connectors, the plugs, the fuse box, the main relay and still the same thing. now, I kept cheking and browsing, and I am 100% percent sure that there is nothing wrong with all of that . But my car is not shifting to overdrive, now I started to look and focus, now is it possible that the problem is related with the lower solenoid? Because, I have not paid attention to it. Is it the cause?

Answer 1

 

P0753 Shift solenoid A