This wasn't on an me7, but the last time I did this I just stole the pin away from the main program and kept setting the output at the top of my function. So if the main did reset the pin(s), it would just be set back on next function call.
A bit crude, but it worked for me. Just depends on if the me7 program is agressive about pin setting.
Well in this case I will need a more secure output. But sure, since the ME7 function will be disabled by codeword or patch but it might keep output reset every cycle. I might need to use a logic analyzer or oscilloscope to be sure that i don't get faulty output.
It does not need to be info about the specific 551m ecu.
Dd: