A0
Daikin · FTXS12LVJU 12,000 BTU Wall Mount Mini Split Indoor Unit with Inverter and Quiet Operation
External protection device activated — an external safety device connected to the indoor unit has triggered, shutting down the system
Error A0 on the Daikin FTXS12LVJU 12,000 BTU Wall Mount Mini Split Indoor Unit with Inverter and Quiet Operation means: External Protection Device Activated. The top-ranked community fix is “Test and Replace External Protection Device Module” (medium difficulty, ~60 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.
Indoor Unit PCB Defect
Drain Level System Malfunction
Anti-Freeze Protection Activated
Indoor Fan Motor Malfunction
Swing Flap Louver Motor Malfunction
Air Filter Clogging Detected
Liquid Pipe Temperature Sensor Malfunction
Gas Pipe Temperature Sensor Malfunction
The Daikin FTXS12LVJU 12,000 BTU Wall Mount Mini Split Indoor Unit with Inverter and Quiet Operation has 8 other known error codes:
Error code A0 also appears on 2 other Daikin models:
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