Sub-Zero Refrigerator Freezer Error Codes – How to fix? by KatyApplianceRepair.com 

Sub-Zero refrigerators and freezers use built-in error codes
to signal specific issues. Use the table below to identify your
code and click through for detailed troubleshooting.

Sub-Zero Error Code Reference

Code	Indication	Details
EC 05	Thermistor fault — inconsistent temperature readings in the refrigerator cabinet	View fix
EC 06	Thermistor fault — inconsistent temperature readings from the evaporator sensor	View fix
EC 07	Thermistor fault — inconsistent temperature readings in the freezer cabinet	View fix
EC 08	Thermistor fault — inconsistent temperature readings from the freezer evaporator sensor	View fix
EC 10	Refrigerator too warm — possible door left open or temperature rising	View fix
EC 11	Upper cabinet door has been open too long — temperature rising	View fix
EC 12	Refrigerator compartment temperature too warm — similar to EC 10	View fix
EC 13	Refrigerator compartment temperature too warm — similar to EC 10	View fix
EC 15	Sealed-system fault — unit not maintaining temperature	View fix
EC 20	Defrost underheat — no voltage feedback through Gray/White wire at defrost start	View fix
EC 21	Defrost overheat — evaporator temperature exceeding safe limits during defrost	View fix
EC 22	No voltage feedback through Gray/White wire at defrost start — wiring or defrost fault	View fix
EC 23	Defrost overheat combined with no voltage feedback — similar to EC 21 + EC 22	View fix
EC 24	Defrost underheat — heater not reaching required temperature	View fix
EC 30	Icemaker not working — water valve or mechanical jam detected	View fix
EC 38	Multiple excessive compressor run times or evaporator thermistor fault	View fix
EC 40	Excessive freezer compressor run — freezer not reaching set temperature efficiently	View fix
EC 50	Excessive refrigerator compressor run — refrigerator not reaching set temperature efficiently	View fix
EC 55	Zone/compartment thermistor shorted — temperature sensor failure	View fix
EC 80	Variable-speed compressor — high differential pressures or low supply voltage	View fix
EC 85	Variable-speed compressor overheating — excessive current draw or refrigerant leak	View fix
EC 86	Communications failure — wiring fault between the variable-speed compressor and the main control board	View fix
EC 90 5 80	Communication fault between the display board and main control board	View fix
EC 90 H 80	Communication fault between the display board and main control board	View fix
EC 90 H 82	Communication fault — variant of EC 90 series indicating board communication failure	View fix
EC 90 H 83	Communication fault — variant of EC 90 series indicating board communication failure	View fix
EC 90 H 84	Communication fault — variant of EC 90 series indicating board communication failure	View fix
EC SU	Display cable fault (blue wire) — wiring or defrost-related issue	View fix
Flashing Service	Service indicator flashing — the control board has detected a persistent fault	View fix

Error Code Groups

• EC 05–08: Temperature sensor (thermistor) faults
• EC 10–13: Temperature / door warnings
• EC 15–24: Defrost and sealed-system issues
• EC 30–55: Compressor, icemaker, and thermistor faults
• EC 80–86: Variable-speed compressor issues
• EC 90 series: Main board communication faults