Problem started with a check engine light, Code p0745 and an intermittent hard shift in 1st and second gear.
You are looking at the pressure control solenoid inside the transmission. One wire is the control wire and the other 1 inch wire, going to an eyelet, is the ground. That crimp had failed over time and started causing an intermittent hard shift from maxed out line pressure. We were able to see a perfect looking control signal on our scope even during the failure but found the current would drop to zero. After pulling the pan and inspecting we found we could grab the wire and lightly pull it right out of its crimp. A little solder and a re-crimp and all is well. Suspect the crimp was never tight enough and over time the arcing eroded away enough wire until it completely failed. This is similar to a spark plug electrode wearing away and at some point causing a misfire.
At Nelsons Automotive of Pewaukee, we specialize on hard to fix Japanese car repairs just like this one.