Nice work.
Current operation?
* 12v Power Applied
* Module waits for a preset timeout period
* Module simulates button press for TC off, simulates five second button hold for SC off
You may be able to modify the programming as so...
* 12v power applied
* module immediately checks for button being held
* If held it checks non-volatile memory and toggles between one of three defaults: Auto TC Off / Auto TC+SC Off / Leave TC+SC On
* Module waits for a preset timeout period
* Module simulates button press according to the default; whether TC Off (single press), TC+SC Off (hold for five seconds), leave TC+SC on (no button presses simulated).
So in a nutshell, to change the default, one would hold the button for at least a full second (or two) after ignition on.
(note: SM = Sport Mode = SC = Stability Control ; TC = Traction Control)