1998 Buick Regal ECM

Manual says that: To prevent the possibility of permanent control module damage, the ignition switch MUST always be OFF when disconnecting power from or reconnecting power to the module. This includes unplugging the the module connector, disconnecting the negative battery cable, removing the module fuse, or even attempting to jump your dead battery using jumper cables. The vehicle runs fine other than the noise and idling too fast. I have tested the voltage coming to all 3 of them and I know that the idle air control valve is alright from a trouble shooting guide. I had to read the resistance but it came up ok. So it all leads me to the ECM. Why would all 3 be bad on both motors? Unlikely huh?