Fujitsu · Heat pump

41 Room (intake air) temperature sensor error

Medium severity Fujitsu ductless split/multi/VRF (general code list)Fujitsu wall-mounted 7-15 (NA ASU/AOU type)Fujitsu slim duct ARU 7-18 (LL type)

What the control is telling you

The room thermistor reads open or shorted. Indoor lamps: OPERATION (green) flashes 4x, TIMER (orange) flashes 1x, ECONOMY (green) flashes fast nonstop; wired remote shows 41.

Applies to: Fujitsu ductless heat pumps: Fujitsu ductless split/multi/VRF (general code list), Fujitsu wall-mounted 7-15 (NA ASU/AOU type), Fujitsu slim duct ARU 7-18 (LL type)

Likely causes

Plug loose or on wrong header
Thermistor failure
Main PCB failure

Test and repair steps

Check the sensor plug on the board is seated and on the right connector, and the lead is not cut or pinched.
Unplug the thermistor and measure its resistance; compare with the resistance/temperature chart in the service manual. Open or shorted = replace.
With the plug connected, check for about DC 5.0 V across the thermistor terminals on the board; no voltage = board fault.
Cycle power after any repair and confirm the code does not return.

Settings for these units

Operating range and service space · Fujitsu multi-zone outdoor 18/24 type

Other codes on the same units

32 Indoor main PCB error (EEPROM / model info)
33 Indoor fan motor power consumption error
35 MANUAL AUTO button error
39 Indoor fan motor power supply error
42 Indoor coil (heat exchanger middle) sensor error
44 Human (occupancy) sensor error
51 Indoor fan motor error
52 Indoor electronic expansion valve error

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Source: Fujitsu All Fujitsu split - multi - VRF (generic code list) codes.pdf - section error code table (indoor LED flashes); Fujitsu Wall-mounted 7-9-12-15 (North American trilingual, UTY-RNNUM remotes; e.g. ASU9-12-15 RLF1-RLS familie.pdf - section 14 Error codes; Fujitsu Wall-mounted KMCG (ASEH-AOEH 07-14) - Fujitsu UK; same error-code scheme as NA ASU-AOU units service S.pdf - section 3 Troubleshooting, 2 Troubleshooting with error code; Fujitsu Slim duct AR07-09-12-14-18 (ARU-ARYG LL-type equivalent) installation P-N 9381858064.pdf - section 14 Error codes. Summarized in our own words; check the original manual for your model.

Homeowner looking at this code? See what it means for you and when to call a technician.

For licensed technicians. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Shut off power and gas before servicing, never bypass a safety control, and follow the manufacturer’s manual for the exact model; it and local codes always take priority. HVACopedia is not affiliated with any manufacturer; brand and model names only identify the equipment.