Mitsubishi Air Conditioner Error Code MT2

MT2 is a maintenance signal output indicating that the inverter's cumulative energization time has reached or exceeded the threshold set in parameter Pr.687. It is a scheduled maintenance reminder, not a system fault or component failure. The code is designed to alert technicians that a preset operating hour interval has elapsed and that service is due. Once appropriate maintenance is performed and the timer is reset, the signal clears.

The MT2 signal is a maintenance reminder and does not indicate an active component failure, so the unit will typically continue to operate. However, running the system beyond the maintenance interval without servicing it can lead to reduced efficiency or undetected wear. It is advisable to schedule a service visit promptly to address whatever maintenance the timer was set to flag.

Service costs following an MT2 alert vary depending on what maintenance tasks are required and local labor rates, but a routine maintenance visit typically ranges from $80 to $250. If the service reveals additional issues such as refrigerant recharge needs or component wear, costs can range higher, potentially from $150 to $500 or more depending on parts and labor involved. Getting a detailed estimate from a certified technician before work begins is recommended.

Fixing MT2 involves completing the maintenance tasks that correspond to the purpose for which the timer was originally configured, such as filter cleaning, refrigerant checks, or electrical inspections. After completing the required service, the cumulative energization timer must be reset and parameter Pr.687 should be reviewed to confirm the next interval is set correctly. A qualified technician with access to the inverter parameter settings should perform this process.

A simple power cycle or reset of the unit will generally not clear MT2 because the cumulative energization timer in the inverter continues to reflect that the Pr.687 threshold has been met. Clearing the code requires resetting the maintenance timer through the inverter parameter settings, typically after completing the required maintenance work. Resetting without performing the maintenance is not recommended.