Did the check engine light go away?
As to all this "shorted out" stuff, there's no engine code that says "it's shorted out."
The engine code basically points at a part and says "Something is wrong with what I'm being told by this part."
As an example, if you get an oxygen sensor code, it could be a bad oxygen sensor, or it could be that the oxygen sensor is working just fine and is detecting a problem, which is what it's there to do.
Too many mechanics these days see an engine code and immediately replace whatever part the code points to without doing any actual diagnostic work to see why the code was thrown in the first place.
It sounds to me like you've found one of these mechanics.
Start by telling us what car we're talking about here.