Fujitsu 15,000 BTU 25 SEER Halcyon Wall-Mount Mini Split with Energy Saving Mode 11 Error Fix: Indoor Room Temperature Thermistor Error

Error code 11 on the Fujitsu 15,000 BTU 25 SEER Halcyon Wall-Mount Mini Split with Energy Saving Mode means: Indoor Room Temperature Thermistor Error. The indoor room temperature sensor has failed or is reading out of range — on newer systems this code may also indicate a serial communication error between indoor and outdoor units (code 11.2 sub-variant); check the thermistor connector on the indoor PCB; measure resistance (typically 10K ohms at 77°F/25°C); a disconnected or corroded connector is a common cause; if the sensor tests good, check for communication issues between units

The most successful fix is "Test and Replace Indoor Room Temperature Thermistor Sensor" (medium difficulty, ~45 minutes). Estimated DIY cost: $15-$25. HomeMD has 2 community-ranked fixes for this error.

This error is rated medium severity. It should be addressed soon, but your appliance may still function in a limited capacity.

Yes — the top-ranked community fix ("Test and Replace Indoor Room Temperature Thermistor Sensor") is rated medium difficulty and takes about 45 minutes. Tools needed: Phillips screwdriver, Digital multimeter.

DIY cost: $15-$25. Professional repair typically costs $110-$140. Many homeowners save money by trying the top-ranked community fix first.

The Fujitsu 15,000 BTU 25 SEER Halcyon Wall-Mount Mini Split with Energy Saving Mode has 8 other known error codes, including: 01 (Indoor Unit PCB Error), 02 (Communication Error — Indoor to Outdoor Unit), 03 (Communication Error — Remote Controller to Indoor Unit), 04 (Outdoor Unit PCB Error), 05 (Outdoor DC Fan Motor Open/Short Circuit), and 3 more.

Error code 11 also appears on 8 other Fujitsu models: 12,000 BTU 18 SEER Slim Duct Mini Split, 8 in Height, Quiet Operation, 12,000 BTU 25 SEER Halcyon Wall-Mount Mini Split with WiFi Control, 24,000 BTU 19 SEER Wall-Mount Mini Split with Low Ambient Cooling, 36,000 BTU 18 SEER Multi-Zone Heat Pump Outdoor Unit, 48,000 BTU Multi-Zone Heat Pump Outdoor Unit, 9,000 BTU 33 SEER Halcyon Wall-Mount Mini Split, WiFi Ready, and 2 more. The fix may vary by model, so check each model's specific page for tailored repair steps.