Fujitsu General 11 fault code

What it means

Serial communication error (indoor ↔ outdoor)

The serial link between indoor and outdoor has failed. The manual splits this by direction: serial reverse transfer error is logged at the outdoor unit, serial forward transfer error at the indoor unit — the interconnect and both PCBs are the suspects either way.

Safety: Safe isolation before opening terminal covers — mains present on the interconnect.

UK models this code applies to

From the Fujitsu General service literature we hold (Fujitsu General ASEH07/09/12/14KMCG service manual (official UK webstore), error-code table + troubleshooting; cross-checked against SR_AS092EF_01. All 23 codes verified model-specific 2026-07-16.) — not a scraped list.

Now the harder half: proving what caused it

11 names a symptom, not a root cause. In the app, the same code opens a guided investigation: what to measure first, the expected values for your exact model, and an honest verdict — including “nothing in this machine is broken” when that's what the readings say.