Mitsubishi Error Code 1: Indoor/Outdoor Mismatch
Warning: Your Mitsubishi HVAC system has detected an indoor/outdoor unit mismatch, which could lead to system damage if not addressed.
LED Blink Pattern
LED blinks 1 time.
How to Fix Mitsubishi Code 1
- Check the batteries in your remote control and replace them if necessary.
- Ensure that the remote control is properly paired with your HVAC system.
- If the issue persists, call a professional HVAC technician to diagnose and repair the problem.
How to Reset Mitsubishi Code 1
- 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 1 Mean?
Mitsubishi's error code 1 indicates that the indoor and outdoor units are not communicating properly. This could be due to a faulty communication wire, a problem with the control board, or an issue with the remote control. The system is designed to prevent damage by displaying this error and shutting down. However, it's important to resolve the issue to restore full functionality.
Common Causes
- Faulty communication wire between indoor and outdoor units
- Issue with the control board in either the indoor or outdoor unit
- Problem with the remote control or its batteries
Diagnostic Steps
| If... | Check | Expected |
|---|---|---|
| The remote control is not working | Replace the batteries and try pairing the remote again. | Remote should work properly after replacing batteries and re-pairing. |
| The remote control is working but the error persists | Inspect the communication wire between the indoor and outdoor units for any damage or disconnection. | Wire should be intact and properly connected. |
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 |
|---|---|---|---|
| Communication Wire | 72010-00-00 | — | Find Part |
| Control Board | 72008-00-00 | — | Find Part |
Related Codes on Same Models
Other codes that affect the same Mitsubishi model families as 1.
| Code | Description | Severity |
|---|---|---|
| 2 | Power Supply Phase Error | Warning |
| 3 | Communication Error | Warning |
| 4 | Inverter Error | Warning |
| 5 | Outdoor Thermistor Open/Short | Warning |
| 6 | Indoor Freeze/Overheat | 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 |