Why would I still have the same prob if I replaced ALL the Solenoids? on 2000 Ford Taurus

I have a 2000 Ford Taurus and it will not shift out of 1st gear. The light came on and said: Code PO750. Replaced all the solenoids and still the same problem and code came up. Replaced gear shift solenoid A. (All were replaced). Still same problem. Could it be wiring?

Get Your Car Fixed at a RepairPal Certified Shop.
We certify shops based on expertise, quality work, and verified customer reviews
1 answer
Is the diagnosis being done with a 'code reader or a scan tool with live data to observe? Need to know what the TCM is commanding the solenoids to do. go from there.