It takes correct timing which is easy to stuff up lol
The codes will display by the engine check light flashing 1-10 times then a pause, then again 1-10 times, pause, flash again, pause, flash again.
Each time it flashes, write down how many times it flashed before the pause (if it flased 10 times, write down a zero).
This will give you your error/s in a four number sequence.
The Ecu is behind/above the glovebox but it is quite uneventful to look at.