Mitsubishi Electric · PAR-21MAA MA Remote Controller
The indoor unit has detected an error in transmitting communication signals to the outdoor unit. This suggests a problem with the indoor unit's communication circuit or the signal path itself, preventing it from sending control commands or status updates.
Click steps to track your progress.
Verify the indoor/outdoor connecting wire terminations match the wiring diagram for correct connection.
Inspect the indoor/outdoor connecting wire and power supply for signs of electrical noise interference that could disrupt signal transmission.
Cycle power to the unit (turn off, then on again) to re-check for the error.