Mitsubishi Error Code U1: High Pressure Trip
Warning: Your Mitsubishi HVAC system has experienced a high pressure trip. It's safe to operate, but you should schedule a professional repair soon.
How to Fix Mitsubishi Code U1
- Check and replace your air filter if it's dirty.
- Turn off your HVAC system and wait for the pressure to equalize (about 24 hours).
- If the system still doesn't work, call a professional HVAC technician.
How to Reset Mitsubishi Code U1
- 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.
What does U1 mean?
The U1 error code on your Mitsubishi HVAC system indicates that the high pressure switch has been activated, causing the system to shut down. This is a safety feature designed to prevent damage to the compressor. The most common causes of this error are a refrigerant leak, a faulty expansion valve, or a clogged air filter.
Affected Models
Replacement Parts
| Part | OEM Number | Est. Cost |
|---|---|---|
| High pressure switch | 510140-0000 | — |
| Expansion valve | 510180-0000 | — |
| Refrigerant | — | — |
Related Codes on Same Models
| 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 |
| 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 |