Transmission overheating code

Thanks for taking the time to read my post!
So I get the code that my transmission is overheating. I changed the fluid, still get the code. Changed the sensors which means dropping the pan again and change the whole harness, which I got from the factory. Still get the code. I can’t find a bad wire anywhere. I even installed an aftermarket gauge and after installing a trans cooler, the temp stays around 130-135 when hot.
Anybody else have this issue? Could it be a bad ECU?

 

It could potentially be a faulty ecu but you're getting into the realm of just throwing parts at the problem until it's fixed now. Might make sense to take it to a dealer or find a good Toyota mechanic so they can hook it up to Techstream and check the issue with that. Or you could do that yourself if you have a laptop and want to invest the time into getting Techstream to work. I've done it before, it can be a real pain but it's a handy tool to have. Requires purchasing a special cable as well. Google Toyota Techstream and do a little research on it.