1) considering the fault, you really are at a great disadvantage if you can't read a w/diagram - perhaps your neighbour could help out?
2) sorry, ECM = ECU = ECM - i live in ireland.
3) you said initially that you replaced the ECM/ECU when your neighbour tested with a reader - he must have detected something(??).
you will find wiring schematics, ignition testing procedures etc & a wealth of other hyundai tech info
here [inc DTC (dianostic trouble codes) codes detected by the reader].
this type of fault can ultimately damage your wallet by replacing uneccessary parts.
the relevant wiring diagram & a simple digital multimeter are
nearly always your best friends.