It looks like we've missed each other.
If it is the circled item above (if not let me know and I can address the correction), then that would be the ignition failure sensor.
The ignition failure sensor is not very well known particularly among independent shops and auto parts stores... you pretty much have to talk to a Mitsubishi person to get any familiarity with it. The reason for this is that it was only used for about 3 years with the 2.4 engine (~98-~01), so there isn't a lot of exposure to general mechanics and parts jockeys etc.
The purpose of the ignition failure sensor is not exactly what it sounds... it is more like a fusible link for the ignition system. If the ignition failure sensor picks up a heavy load from one of the coils (indicating a shorted coil) the ignition failure sensor will blow out preventing current from reaching the coils, in turn protecting the computer from a dead short. This was later replaced with just a traditional fuse protection for 2002+ models.
Testing the sensor is pretty easy for the most part.... if the engine runs, you know it is good of course. If the engine does not run, then unplug an ignition coil and check for voltage with the key on... if there is voltage, the ignition failure sensor is working; if there is no voltage, it may be blown out.
Basically.... it interrupts the 12V supply to the two coils, so as long as your coils have 12V with the key on, the ignition failure sensor is OK.