E6-EF
Indoor/Outdoor Unit Communication Error
Mitsubishi Electric · PAR-21MAA MA Remote Controller
What does E6-EF mean?
This range of codes (E6 through EF) indicates a communication error between the indoor and outdoor units, as displayed on the remote controller LCD. For specific diagnostic details regarding the root cause, further reference to the detailed error code list in the manual is required.
Common Causes
- Disruption in the communication protocol between indoor and outdoor units.
- Incorrect wiring configuration for the communication lines (e.g., polarity reversed).
- Electromagnetic interference corrupting communication signals.
- Failure of the communication interface chip on either the indoor or outdoor unit.
Repair Steps & Checklist
Click steps to track your progress.
- 1
Refer to the 'Error code list' in section 'V.4.2.Error code list' of the complete manual for specific diagnostic information related to E6-EF codes.
- 2
Verify the S1, S2, S3 communication wiring between the indoor and outdoor units for secure connections, correct polarity, and continuity.
Verified technical data. Last updated: March 2026
Related Faults
Source: Mitsubishi Electric PAR-21MAA MA Remote Controller