How to tell a "fake" ECU from a real one

This is why I asked if anybody had a cct diagram. Don't think you can 'just bolt the transistor to the metal case'. The metal body of this type of transistor is the Collector, one of the three electrical connections of the transistor, & is part of the electrical cct. I am almost sure it is electrically 'hot' & cannot be connected to the case because the case is grounded.