Ud
Mitsubishi · MSZ-GL12NA 12,000 BTU Wall-Mount Ductless Mini-Split Indoor Unit
The M-NET or DIII-NET centralized building management controller is experiencing a network-level communication failure. Data packets are not being transmitted or received correctly on the management bus. Check M-NET bus wiring for proper termination, correct topology, and absence of shorts or opens. Not applicable to standard residential installations without centralized control.
Error Ud on the Mitsubishi MSZ-GL12NA 12,000 BTU Wall-Mount Ductless Mini-Split Indoor Unit means: M-NET Centralized Controller Transmission Error. The top-ranked community fix is “Test M-NET Bus Wiring Continuity and Replace Faulty Sections” (medium difficulty, ~45 min, DIY cost: $10-$20). 2 community-ranked fixes available below.
Published February 2026 · 2 fixes · mini split
Content is based on manufacturer service documentation, community repair experience, and OEM technical bulletins. Always verify with your owner's manual.Learn about our editorial standards.
While many mini split repairs can be done safely at home, consider hiring a qualified technician if:
Average professional repair cost for this issue: $150-$250.
mini_split · 2 fixes
mini_split · 2 fixes
mini_split · 2 fixes
mini_split · 2 fixes
mini_split · 2 fixes
heat_pump · 2 fixes
mini_split · 2 fixes
heat_pump · 2 fixes
heat_pump · 2 fixes
heat_pump · 2 fixes
mini_split · 2 fixes
mini_split · 2 fixes
heat_pump · 2 fixes
mini_split · 2 fixes
Remote Controller PCB Error
Remote Controller Signal Receiving Error
Remote Controller Communication Error
Indoor Unit PCB Processor Error
Indoor/Outdoor Communication Error (Legacy)
Indoor Unit EEPROM Error
Indoor Fan Motor Error
Indoor Unit Overcurrent Protection
The Mitsubishi MSZ-GL12NA 12,000 BTU Wall-Mount Ductless Mini-Split Indoor Unit has 8 other known error codes:
Error code Ud also appears on 14 other Mitsubishi models:
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