I found this on another Mitsubishi forum and wanted to pass it along. It is instructions on how to reset the maintenance reminder (look like a little wrench on the LCD display). Here is an example picture:
I can confirm that it works for the North American Mirage 1.2 liter manual. I experimented with and can confirm that the ''OFF Display'' setting works as described below. I cannot confirm if the NAS codes work or are displayed as described below but I imagine they would at least be similar enough to figure out.
Taken from:
http://www.evolutionm.net/forums/09-ralliart-how-installations/450643-how-reset-mileage-counter-service-inspection.html
Some useful info from the service manual - here is how to reset your Service Reminder, Change the Maintenance Schedule (factory default is 6 months/7,500 miles but those of us requiring the "Severe Maintenance" schedule can change it as outlined below), or inactivate it altogether:
HOW TO CANCEL THE SERVICE REMINDER WARNING
1. Turn the ignition switch to the "OFF" position.
2. By operating the meter information switch, the warning period is displayed on the multi information display.
3. Press the meter information switch once for 1.2 seconds or longer.
4. The service reminder indicator flashes.
5. While the service reminder indicator flashes, press the meter information switch once for less than 1.2 seconds.
6. The service reminder indicator is turned ON, and "CLEAR" is displayed on the multi-information display for 3 seconds.
7. After "CLEAR" is displayed for 3 seconds, the warning period to the next time is displayed.
HOW TO SET THE SCHEDULE
1. Turn the ignition switch to the "OFF" position.
2. By operating the meter information switch, the warning period is displayed on the multi information display.
3. Press the meter information switch once for 1.2 seconds or longer.
4. The service reminder indicator flashes.
5. While the service reminder indicator flashes, press the meter information switch 3 times consecutively for 1.2 seconds or longer (per press).
6. The service reminder indicator is turned ON, (may display NOR) and the current schedule is displayed on the multi information display.
7. While the current schedule is displayed, press the meter information switch 3 times consecutively for less than 1.2 seconds.
8. The multi information display is shifted to the schedule selection mode.
9. When the meter information switch is pressed for less than 1.2 seconds, the schedule is shifted, and when the switch is pressed for 1.2 seconds or longer, the displayed schedule is set.
10. The schedule set in Step 9 is displayed for 3 seconds, and the warning period to the next time is displayed.
ScheduleWarning types Warning criteria
NAS 10 (initial setting) Elapsed time (month) Every 6 elapsed months
Driving distance (miles) Every 7,500 miles of driving distance
Driving distance (km) Every 12,000 km of driving distance
NAS 11 Elapsed time (month) Every 3 elapsed months
Driving distance (miles)Every 3,750 miles of driving distance
Driving distance (km) Every 6,000 km of driving distance
NAS 20 Elapsed time (month) Every 5 elapsed months
Driving distance (miles) Every 5,000 miles of driving distance
Driving distance (km) Every 8,000 km of driving distance
NAS 21 Elapsed time (month) Every 4 elapsed months
Driving distance (miles) Every 3,750 miles of driving distance
Driving distance (km) Every 6,000 km of driving distance
HOW TO INACTIVATE THE SERVICE REMINDER
FUNCTION
By setting to "OFF Display" or "Function OFF" when the schedule is set, the service reminder function can be inactivated.
When "OFF" is selected
_ Even when the check warning period is reached, the service reminder display is not displayed.
_ Even if the service reminder screen is displayed by the meter information switch
operation, "OFF" is displayed.
.
Hope this helps.