Error Code E6
Mitsubishi Electric Air Conditioner
Severity:What Does This Error Mean?
Mitsubishi Electric Error E6 means the indoor unit has lost communication with the outdoor unit. A power reset often clears transient E6 errors. If E6 returns, the communication wiring or indoor/outdoor PCB needs professional inspection.
Affected Models
- Mitsubishi Electric MSZ Series
- Mitsubishi Electric SRK Series
- Mitsubishi Electric MSZAP Series
- Mitsubishi Electric MSZEF Series
Common Causes
- Communication wiring between indoor and outdoor units damaged or loose
- Indoor unit PCB communication chip failed
- Outdoor unit PCB failed
- Power interruption or surge corrupted communication settings
How to Fix It
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Perform a power reset.
Turn the AC off at the indoor controller or remote. Turn off the circuit breaker or isolator for both the indoor and outdoor units for 5 minutes. Restore power and switch the system on. E6 caused by a communication glitch will clear and not return.
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Check the communication cable.
The indoor and outdoor units are connected by a 3-core or 4-core communications cable in addition to the power wiring. If the cover of the indoor unit can be safely removed, check that all wiring connectors are firmly seated. Do not work on live wiring — isolate both units first.
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Look for storm or power surge damage.
Lightning strikes and power surges can damage the communication PCB in either unit without any visible burn marks. If E6 appeared after a storm, mention this to the technician — it helps narrow down which board to test first.
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Note the full diagnostic code.
Some Mitsubishi Electric models append a sub-code to E6 (e.g. E6-01, E6-02) which identifies whether the fault is indoor-side or outdoor-side. Note the sub-code if displayed and provide it to the service technician.
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Book a Mitsubishi Electric authorised technician.
Use the Mitsubishi Electric website's service locator to find an authorised agent. Unauthorised repairs may void the manufacturer warranty. Mitsubishi Electric split systems typically carry a 5-year parts and labour warranty when installed by a licensed contractor.
When to Call a Professional
If a power reset does not clear Error E6, the communication wiring or a PCB has failed. Call a Mitsubishi Electric-authorised service agent — do not attempt wiring repairs without electrical qualifications.