Mitsubishi MSZ-GL09NA 9,000 BTU Wall-Mount Ductless Mini-Split Indoor Unit U2 Error Fix: Power Supply Voltage Error / Phase Unbalance

Error code U2 on the Mitsubishi MSZ-GL09NA 9,000 BTU Wall-Mount Ductless Mini-Split Indoor Unit means: Power Supply Voltage Error / Phase Unbalance. The supply voltage is outside the acceptable operating range (typically +-10 percent of rated voltage) or the phases are significantly unbalanced on 3-phase units. Overvoltage or undervoltage can damage electronic components. Measure voltage at the unit disconnect — should be 208-230V single phase for most residential models. Check for voltage drop on long wire runs. Correct any wiring issues or contact the utility company if voltage is consistently out of range.

The most successful fix is "Correct Wiring Issues and Coordinate with Utility for Voltage Stabilization" (hard difficulty, ~180 minutes). Estimated DIY cost: $0-$50. HomeMD has 2 community-ranked fixes for this error.

This error is rated critical severity. It is generally not urgent and can often be resolved with a simple DIY fix.

Yes — the top-ranked community fix ("Correct Wiring Issues and Coordinate with Utility for Voltage Stabilization") is rated hard difficulty and takes about 180 minutes. Tools needed: Clamp meter, Digital multimeter, Insulated screwdrivers, Wire strippers.

DIY cost: $0-$50. Professional repair typically costs $300-$500. Many homeowners save money by trying the top-ranked community fix first.

The Mitsubishi MSZ-GL09NA 9,000 BTU Wall-Mount Ductless Mini-Split Indoor Unit has 8 other known error codes, including: E1 (Remote Controller PCB Error), E2 (Remote Controller Signal Receiving Error), E3 (Remote Controller Communication Error), E4 (Indoor Unit PCB Processor Error), E5 (Indoor/Outdoor Communication Error (Legacy)), and 3 more.

Error code U2 also appears on 14 other Mitsubishi models: MLZ-KP09NA 9,000 BTU One-Way Ceiling Cassette Indoor Unit, MSZ-EF15NA 15,000 BTU Designer Series (Kirigamine Zen) Wall-Mount Indoor Unit, MSZ-FH12NA 12,000 BTU Hyper-Heat H2i Wall-Mount Indoor Unit, MSZ-FS06NA 6,000 BTU Compact Wall-Mount Indoor Unit, MSZ-GL12NA 12,000 BTU Wall-Mount Ductless Mini-Split Indoor Unit, MUZ-GL09NA 9,000 BTU Single-Zone Outdoor Unit, and 8 more. The fix may vary by model, so check each model's specific page for tailored repair steps.