Resetting ECU in 2002 Toyota Celica

I own a 2002 Celica Toyota GT with 416,736 miles yes, you read it right. For 3 years run car with engine light on, knew was the catalytic converter, need a new one but couldn’t afford it so I let it go. Just change catalytic converter and oxygen sensors but light still on. I google and find out I have to run my car 50-100 miles so computer starts to read new catalytic functions. Would the engine light turn off itself or have to take it back to reset ECU?

My interpretation is that the light will go off after you get the hundred miles on it. If the CEL is still on, have the codes read and see if there are other error codes.

Thank you, would do it. It’s 37 miles so still have to wait and see.