Pcm on 99 f-150 only sending 1.5 volts to crank

computers have numbers on them, and this for a very important reason. Even on same year model vehicles, sometimes the color coding, and pins do not match. I had problems from check engine lights to cars not starting at all. Unlike mechanical things where physicall appearance tells you they are the same. If you look inside the computer itself. There is no way for you to tell if they are the same or not. For one thing the main chip there are programmed, and which may look the same but with diffrent program. I suggest using a computer of the same year. At least there is a better chance of matching. It is a lot better than getting from a diffrent year which may have a diffrent program or even a diffrent circuit.