FoxESS
Error 11
SCI Fault / Internal Communication Error
Internal serial communication fault within the inverter.
Common causes
Firmware issueInternal hardware faultPower supply instability causing comms reset
What to check
STEP 1
Power cycle the inverter (AC off, DC off, wait 5 minutes). Check if fault clears on restart
STEP 2
Check firmware version and update via Fox ESS app if newer version is available
Escalate if
Fault returns after power cycle and firmware is up to date — internal hardware fault, escalate
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