Mitsubishi Air Conditioner Error UC

⚡ Quick Answer: The Mitsubishi Air Conditioner UC error code indicates a communication failure between the indoor and outdoor units, often triggered by the compressor... ✅ DIY Fixable

What Does Error UC Mean?

The Mitsubishi Air Conditioner UC error code indicates a communication failure between the indoor and outdoor units, often triggered by the compressor's self-protection mechanism due to abnormal electrical or mechanical conditions. This results in the unit stopping suddenly, with the compressor either not running or cycling frequently, leading to reduced cooling or heating performance.

Common Symptoms:

  • Unit stops suddenly with UC displayed on controller
  • Compressor not running or repeatedly starting and stopping
  • Possible reduced cooling/heating performance

Possible Causes

  • Compressor self‑protection activation due to abnormal electrical or mechanical conditions (medium)

How to Fix Error UC

DIY Fix Basic Checks & Power Reset

  1. Turn off the air conditioner from power at the breaker or main switch.
  2. Wait for 5–10 minutes to let internal protections reset.
  3. Turn power back on and restart the unit.
  4. Check if error persists.

Technician Only Compressor & Electrical System Diagnostics

  1. Inspect outdoor unit and compressor for signs of overheating, electrical faults, or wiring issues.
  2. Measure compressor current draw and verify it’s within specification.
  3. Check inverter and power module for faults or error logs.
  4. Test pressure sensors and safety switches related to compressor protection.

Parts needed: Compressor motor and protection module, Power/inverter module, Pressure and temperature sensors, Wiring harness

🛑 When to Call a Pro:
  • Unit continues to show UC after reset attempts
  • Unusual noises, burning smells, or no cooling/heating
  • Compressor overheats or trips repeatedly

Next step

Choose the next step for UC

Confirm the diagnosis before ordering. An error code can identify the system involved, but it does not prove that a specific part has failed.

Other parts options

Check related components first; use model search as a fallback.

Possible related component

Temperature Sensor

Monitors the internal temperature to ensure correct operation and prevent overheating.

$15 - $35 · Easy · 15-30 mins

Check fit & price
Possible related component

Wiring Harness

Connects controls, sensors, motors, and other electrical components inside the appliance.

$20 - $120 · Medium · 30-90 mins

Check fit & price
Model number required

Model-compatible Air Conditioner parts

Enter the complete model number to browse compatible replacement parts. This is a model-based parts search, not a diagnosis that a specific component failed.

Find a part that fits my model

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Optional routine care

Maintenance supplies

These products support cleaning or routine upkeep. They are separate from the possible repair components above and are not claimed to fix this error code or symptom.

Maintenance supply

Air Conditioner Fin Cleaner

For routine cleaning of accessible coil fins when permitted by the manufacturer. Disconnect power and follow product and appliance instructions.

View maintenance supply
Maintenance supply

Model-Compatible Washable AC Filter

A reusable filter option only where the appliance supports one. Match the full model, dimensions, and filter specification.

Compatibility check required: use the complete appliance model and compare the existing filter, bag, or specification before ordering.

Find one that fits my model

Affiliate disclosure: As an Amazon Associate I earn from qualifying purchases. Recommendations are based on routine-care relevance, not commission rate.

Technical Specifications

note The previous model-independent part specification was removed. Verify the full model number and diagnosis in the manufacturer's official parts catalog before ordering.
part_number None

Common Questions

What does UC error mean on Mitsubishi Air Conditioner?

The UC error indicates a communication failure between the indoor and outdoor units, often due to the compressor's self-protection function.

Can I fix Mitsubishi Air Conditioner UC error myself?

Yes, you can perform basic checks and a power reset by turning off the AC at the breaker for 5–10 minutes before restarting.

How much does it cost to fix UC error?

Repair costs vary widely, but replacing the compressor or inverter module can range from ¥30,000 to ¥150,000+.

When should I call a technician for UC?

Call a technician if the UC error persists after reset attempts, if you hear unusual noises, or if the compressor overheats.

Data last verified: 2026-07-31

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