Unfortunately, electrical schematics for the ECU are not available from any known source. No one has seen fit to release such documentation from within Mitsubishi, and the ECU is too complex to be easily traced out by hobbyists. If someone does have such diagrams, they are keeping them a secret.
One small consolation may be that the ECU pinout is available in every shop manual.
You can check http://www.lilevo.com/mirage/