Mitsubishi Error Code and Repair Guides - 37 Guides
Mitsubishi HVAC troubleshooting hub with 37 guides for fault codes, alarms, symptoms, parts checks, and repair decisions.
Use this page when your Mitsubishi furnace, air conditioner, heat pump, or mini split is flashing a fault. Start with the exact code, then open the fix guide to diagnose airflow, ignition, sensor, pressure switch, board, or communication problems before you order parts or book a service call.
Tip: search the exact brand, model, and code together, for example "Mitsubishi error code 13" or "Mitsubishi pressure switch fault".
Start With These Mitsubishi Guides
Mitsubishi FAQ
Where should I start with Mitsubishi error codes?
Start with the exact Mitsubishi model and displayed code or alarm, then open the closest guide on this page. Match the symptom, recent service history, and any secondary codes before resetting the equipment or ordering parts.
Do Mitsubishi fault codes always mean a bad control board?
No. Many Mitsubishi codes point to airflow, water flow, sensors, wiring, power quality, filters, switches, or operating conditions. Check the simple causes in the guide before replacing an expensive board.
When should I stop troubleshooting a Mitsubishi fault myself?
Mitsubishi HVAC equipment can hide unsafe ignition, refrigerant, high-voltage, or combustion problems behind a simple blinking code. Stop and use the repair checklist or compare service options when the guide points to gas, refrigerant, line voltage, sealed-system work, food-safety temperatures, or repeated faults after a reset.
| Error Code | What It Means | Guide |
|---|---|---|
| Mitsubishi Mini Split Error Codes | Complete Guide | Fix → |
| Mitsubishi FR-D700 VFD Fault Codes | Mitsubishi FR-D700 guide for OC1, OV3, THT, THM, GF, PE, UVT, cooling fan, braking, motor cable, and parameter faults. | Fix → |
| Mitsubishi P1 Error Code | Mini Split Freeze Protection | Fix → |
| Mitsubishi P5 Error Code | Drain Pump Fault | Fix → |
| Mitsubishi Electric Lift Troubleshooting | Elevator Fault Guide | Fix → |
| Mitsubishi FR-A800 E.OC1 Overcurrent Fault | Mitsubishi FR-A800 E.OC1 fault guide for acceleration overcurrent, ramp time, motor cable insulation, output reactors, load jams, and motor data. | Fix → |
| Mitsubishi MR-J4 Servo Alarm Codes | Mitsubishi MR-J4 servo alarm guide for AL.10, AL.16, AL.30, AL.50, overload, encoder, regenerative, voltage, and amplifier faults. | Fix → |
| Mitsubishi Mini Split E6 Error Code Fix | Diagnose Mitsubishi Mini Split E6 Error Code Fix: likely causes to check, measurements to verify, and repair decisions before parts replacement. | Fix → |
| Mitsubishi Mr. Slim Error Codes: Complete Guide | Complete Mitsubishi Mr. Slim error code guide. Covers all P, E, and U-series fault codes for commercial Mr. Slim PUHZ, PEA, and PKAA series units. | Fix → |
| Mitsubishi City Multi P8 / E6 Error Codes | Causes & Fix | Fix → |
| Mitsubishi CNC Alarm 500 | Causes & Fix | Fix → |
| Mitsubishi CNC Alarm Y96 | Causes & Fix | Fix → |
| Mitsubishi E1 Communication Fault | Mitsubishi E1 means indoor and outdoor units lost communication. Check S-terminal wiring, zone wiring, power supplies, and indoor or outdoor PCBs. | Fix → |
| Mitsubishi E3 Error Code | Indoor Fan Motor Fault Fix | Fix → |
| Mitsubishi E4 Error Code | Causes & Fix | Fix → |
| Mitsubishi E5 Error Code | Drain Pump or Float Switch Fault | Fix → |
| Mitsubishi E6 AC Error Code | Causes & Fix | Fix → |
| Mitsubishi E7 Error Code | Refrigerant Cycle Fault | Fix → |
| Mitsubishi FR Series VFD Fault E6 | Causes & Fix | Fix → |
| Mitsubishi FR-A800 Fault E7 | CPU Error Causes & Fix | Fix → |
| Mitsubishi FR-E800 Fault E6 | Causes & Fix | Fix → |
| Mitsubishi Mini Split E1 Indoor Thermistor Fault | Mitsubishi E1 guide for indoor room thermistor faults, sensor resistance checks, wiring issues, MSZ/MXZ units, and control-board decisions. | Fix → |
| Mitsubishi Mini Split E6 Communication Fault | Mitsubishi E6 means the indoor and outdoor units lost communication. Check S-Bus wiring, fuses, boards, and interference before replacing parts. | Fix → |
| Mitsubishi Mini Split E9 Error Code | Outdoor Thermistor Fault | Fix → |
| Mitsubishi Mini Split P6 Error Code Fix | Diagnose Mitsubishi Mini Split P6 Error Code Fix: likely causes to check, measurements to verify, and repair decisions before parts replacement. | Fix → |
| Mitsubishi Mini Split P8 Overheat Fault | Mitsubishi P8 means the outdoor heat exchanger is overheating. Check coil airflow, fan operation, clearance, refrigerant issues, and thermistors. | Fix → |
| Mitsubishi Mini Split U4 Error Code | Causes & Fix | Fix → |
| Mitsubishi Mini-Split U0 Error Code: Refrigerant Shortage | Mitsubishi U0 guide for refrigerant-shortage faults, leak signs, pressure-sensor issues, service-valve checks, and certified HVAC repair decisions. | Fix → |
| Mitsubishi P4 Error Code | Drain System Fault: Causes & Fix | Fix → |
| Mitsubishi P8 Error Code | Causes & Fix | Fix → |
| Mitsubishi PEX City Multi Error Codes | Mitsubishi PEX City Multi indoor-unit guide for P1, P2, P4, P5, P6, P8, drain, thermistor, float-switch, and coil-freeze faults. | Fix → |
| Mitsubishi PUY Air Handler Error Codes | Mitsubishi PUY guide for City Multi air-handler codes, remote communication, fan faults, drain sensors, EEV errors, and pipe sensors. | Fix → |
| Mitsubishi U1 Error Code | Causes & Fix | Fix → |
| Mitsubishi U2 Error Code | Causes & Fix | Fix → |
| Mitsubishi U3 Error Code | Causes & Fix | Fix → |
| Mitsubishi U6 Error Code | Causes & Fix | Fix → |
| Mitsubishi U7 Error Code | Refrigerant System Fault | Fix → |