We bought our kid an 05 honda civic ex. The bolt that holds the battery connect on to his alternator broke off so we replaced the alternator. Car ran fine for 24 hours no issues. The next day on his way home from work a green flashing key appeared, he lost his rpms, temp gauge, and we can't hook up the code reader it just reads error. The car still starts and drives. We tried resetting the ecu by unhooking the battery after the car driving for 20 minutes. We're lost on what it could be. All the fuses are fine those have been checked.