It is very likely that it was just a loose wire.
A loose ground wire affects many things, as many things share a common ground wire.
A loose power or signal wire would affect just that item.

And it may shock you to know that the ground wire for the brakes ( regen brakes, anyway ) is not in the engine or fusebox. It is under the driver's seat!

Don't question why. Many very smart people put this car together, and there is a logical reason for this, just unknown to you and me and most dealer service techs.