I need help- The service engine soon light is on solid and reduce engine power

What is your question?

light is on solid and car goes 5mph- took it to shop, changed out throttle body for $400.00...now he says the bad throttle body burned the ecu unit and I have to replace that now...costs around $300 for ecu at autozone and labor no idea- can a bad throttle body cause a ecu to burn out? or was It the ecu the whole time and he misdiagnosed it? any help is much appreciated...:)