Trying to repair my ECU.

I took apart a "remanufactured" ECM once to see what they did to it. Description says they fully solder everything and perform any known updates. Reality is, they simply cut a tiny portion of the factory rubber coating to expose the one tiny transistor that failed. They replace only that one part, then squirted some RTV silicone into the void. It wasn't even sealed completely any more.
Definitely attempt that repair yourself, since you can see where the damaged part is.