Ok. I need to know if the Automatic cars have a Transmission Controller Unit? I'm pretty sure they do. I also need to know all the variables that the Transmission Controller Unit takes in to figure out when the shifting points occur. What I know so far is that it takes into account: Throttle Position, Speed. What else does the Transmission Controller Unit take into account? Thanks

On B13's it's built into the ecu.

The car has an SR20DE ECU and I need to know what inputs the ECU takes in to calculate correct shifting points. The thing is that we installed a Simple Digital Systems Programmable Engine Management into the 98 Sentra SE (Automatic) but the thing is...The Ecu is not reading the coreect variable (what i'm asking and need to know) to shift correctly. Also the stock ECU doesnt get any readings on what the engine is doing because it is not being used. Hence the use of the SDS system. So we are going to try and find out the right signals the ecu need to shift correctly. And what i know the ecu needs to shift are vehicle speed and throttle position. I need to know what other variables the ECU needs to figure out the correct shifting points.

This is just an educated guess but I would say RPM is a likely candidate.