Mitsubishi Error Code 6: Indoor Freeze/Overheat
Warning: Your Mitsubishi HVAC system has detected an indoor unit temperature issue. It's safe to operate, but needs professional attention.
LED Blink Pattern
LED blinks 6 times.
How to Fix Mitsubishi Code 6
- Check and replace your air filters if they're dirty
- Ensure all vents are open and unobstructed
- Try adjusting your fan speed or air direction
- If no improvement, call a professional HVAC technician
How to Reset Mitsubishi Code 6
- Turn off the unit using the remote control or wall controller.
- Turn off the circuit breaker for the outdoor and indoor units. Wait 60 seconds.
- Restore power at the breaker.
- Turn the unit on with the remote control. If the error returns, the fault needs professional diagnosis.
Resetting clears the code from the display but does not fix the underlying fault. If the code returns after reset, proceed to the diagnostic steps above.
What Does Mitsubishi Error Code 6 Mean?
Mitsubishi's error code 6 indicates that your indoor unit's temperature has either dropped too low (freeze) or risen too high (overheat). This could be due to airflow obstruction, refrigerant issues, or a faulty temperature sensor. The system will continue to operate, but with reduced performance to prevent further damage.
Common Causes
- Blocked airflow due to dirty filters or closed vents
- Low refrigerant levels or a refrigerant leak
- Faulty temperature sensor in the indoor unit
- Incorrect fan speed or air direction
Diagnostic Steps
| If... | Check | Expected |
|---|---|---|
| Indoor unit is covered in ice | Refrigerant pressure using a manifold gauge set | Low pressure |
| Indoor unit feels excessively hot | Temperature of the indoor unit's heat exchanger | Below 120°F (49°C) |
Applicable Mitsubishi Models
- City Multi (VRF)(electric)
- City Multi (Y)(electric)
- Diamond (PJ)(electric)
- Diamond Plus(electric)
- Diamond Series(electric)
- Ducted Systems(electric)
- M-Series(electric)
- MSZ(electric)
- MSZ Series(electric)
- MSZ-AP(electric)
- MSZ-AP Series(electric)
- MSZ-AP5 Series(electric)
- MSZ-AS(electric)
- MSZ-FD(electric)
- MSZ-FE(electric)
- MSZ-FS(electric)
- MSZ-FS/FD Series(electric)
- MSZ-FT(electric)
- MSZ-FY(electric)
- MSZ-GE(electric)
- MSZ-LV(electric)
- MUZ-FE Series(electric)
- P-Series(electric)
- PUMA(electric)
- PUMY(electric)
- Puff (P-Series)(electric)
Replacement Parts
| Part | OEM Number | Est. Cost | Where to Buy |
|---|---|---|---|
| Indoor Unit Temperature Sensor | 53000-00000 | — | Find Part |
| Refrigerant (R410A) | — | — | — |
Related Codes on Same Models
Other codes that affect the same Mitsubishi model families as 6.
| Code | Description | Severity |
|---|---|---|
| 1 | Indoor/Outdoor Mismatch | Warning |
| 2 | Power Supply Phase Error | Warning |
| 3 | Communication Error | Warning |
| 4 | Inverter Error | Warning |
| 5 | Outdoor Thermistor Open/Short | Warning |
| 7 | Outdoor Freeze/Overheat | Warning |
| E6 | Indoor/Outdoor Communication Error | Warning |
| E9 | Indoor/Outdoor Communication Fault | Warning |
| P1 | Intake Sensor Error | Warning |
| P2 | Indoor Pipe Thermistor Error | Warning |