Not for security reasons, but to reset the ecu for obd2 cars.
I have a h22a w/no cat and i get a check engine light everyother day after i reset.

my question is there a way that i can hook up a switch to reset the ecu without pulling the neg battery cable?? 1st its a PITA with the radio and poping the hood gets old.

with a multimeter i found more than 1 12v source going into the ecu, is there anyway to do this????

 

You could do it fairly easily. There should be only one 12 volt source to the ECU with the ignition off, that would be for the ECU memory. Put a switch on that wire and you are done.