What parts would require more fancy equipment? Induction motors are pretty dead simple and probably built to lower tolerances than the average ICE. An EV has more reliance on fancy electronics, which would be hard to replicate, but that applies to any modern day car too. Think of the engine ECU that controls fuel flow, spark timing, etc. You aren't going to pick one of those up at sparkfun.

Think of a Tesla as a laptop computer with a very large battery bank, some powerful inverters and electric motors.

It has all the complexities of a cluster on wheels, tons of software systems and as a result is hard to diagnose properly.

So the first 'fancy equipment' you will need is a set of proper diagnostics equipment, which is - given the complexity involved - most likely supplied by the manufacturer or not at all.

What Tesla could do - but which they would hate because it is part of their competitive edge - is to release full schematics and software listings, but no other ordinary car manufacturer does this, nor are they required to by law.

Good thing too because if the Toyota ECU was anything to go by the industry would look pretty dumb.