What was the donor vehicle for the trans ECU? Exact same model/year/configuration as yours? You say you are getting a message that it cannot be "reset" and I'm not sure what that means. I think you may need to do more than just remove the learned adaptions in that ECU (which would happen when you disconnect the battery) but instead reprogram it, Does your Techstream set up and cable supposedly have the ability to program the ECU? It appears you are running a clone, not the official Toyota version Techstream Lite with the Mongoose cable? Assuming your 2nd hand ECU is compatible and not smoked, you could pay to access the actual Techstream site, pull down the correct calibration file and reflash that transmission ECU - might need the Mongoose cable. Or, you take it to Dealership and pay to have them flash it (if they would agree) which would likely be cheaper and less likely to damage your ECU. My thoughts but no guarantee it will fix your problem.