Fujitsu AOU18RLXFZH 18,000 BTU Multi-Zone Mini Split System with Inverter Compressor 45 Error Fix: DC Peak Detection Error

Error code 45 on the Fujitsu AOU18RLXFZH 18,000 BTU Multi-Zone Mini Split System with Inverter Compressor means: DC Peak Detection Error. A DC voltage spike has been detected in the inverter circuit — this can be caused by an unstable power supply, voltage surges from the utility, a failing DC bus capacitor on the outdoor PCB, or a short circuit in the compressor motor; check the incoming power supply voltage for stability; inspect the DC bus capacitor for bulging or leaking; this error may occur during startup when the DC bus charges

The most successful fix is "Replace DC Bus Capacitor on Outdoor PCB" (hard difficulty, ~90 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 ("Replace DC Bus Capacitor on Outdoor PCB") is rated hard difficulty and takes about 90 minutes. Tools needed: T20 Torx screwdriver, Digital multimeter, Soldering iron, Desoldering pump.

DIY cost: $15-$25. Professional repair typically costs $120-$180. Many homeowners save money by trying the top-ranked community fix first.

The Fujitsu AOU18RLXFZH 18,000 BTU Multi-Zone Mini Split System with Inverter Compressor 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 45 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, 15,000 BTU 25 SEER Halcyon Wall-Mount Mini Split with Energy Saving Mode, 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, and 2 more. The fix may vary by model, so check each model's specific page for tailored repair steps.