Mitsubishi Electric · PAR-21MAA MA Remote Controller
The indoor unit has detected an error in transmitting signals to the remote controller. This suggests a problem with the indoor unit's communication circuit or the wiring between the indoor unit and the remote controller, preventing it from sending status updates or acknowledgments.
Click steps to track your progress.
Verify the connecting wire between the indoor unit and remote controller is connected correctly at both ends.
Inspect the transmission wire of the remote controller for signs of electrical noise interference.
Cycle power to the unit (turn off, then on again) to re-check for the error.