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

Bewy said
Does anyone have a circuit diagram of the ECU?

Unknown Q3 (case transistor?) could be a MJ150001 NPN
20 AMPERE POWER TRANSISTOR SILICON 140 VOLTS, 250 WATTS
https://www.onsemi.com/pdf/datasheet/mj15001-d.pdf