Hi

Background; I am planning to use megasquirt instead of the original ecu, and I am trying to use as much as possible of the original wiring harness with as little as possible butchering of it...

Question
Does anybody know if the security module and ecu serial communication is two way? Meaning is the security module expecting acknowledgement from ECU on fuel inhibition on/off message or not?

CEL signal for cranking control should not be that big of issue, either programmable out put from mega or timerelay should do the trick.

I attached the wiring diagram to clarify the issue.
Antti