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Sub-Zero Refrigerator error codes
Current records for this brand and appliance type, grouped by verified code pages and common symptom patterns.
Coverage status
Display-code format
This first Sub-Zero batch is limited to United States support pages for 600 Series refrigeration. Codes 05, 06, 07, and 20 provide no customer troubleshooting, while 21 and 24 permit one temperature-gated clear path. Every record keeps food-temperature checks, electrical access, defrost parts, and sealed-system work behind explicit safety boundaries.
Official display-code reference · Verified 2026-07-30
Common themes
These themes help you choose the closest code record, but they are not a diagnosis by themselves.
Before checking a code
Match the exact brand, appliance type, and display code first. Stop if there is water near electrical parts, burning smell, or any visible damage.
Codes
05Error code
Sub-Zero documents 05 on 600 Series refrigeration as a refrigerator-cabinet thermistor reading that is open, shorted, or repeatedly erratic.
06Error code
Sub-Zero documents 06 on 600 Series refrigeration as a refrigerator-evaporator thermistor signal that is open, shorted, or inconsistent.
07Error code
Sub-Zero documents 07 on 600 Series refrigeration as a freezer-cabinet thermistor reading that is open, shorted, or repeatedly erratic.
20Error code
Sub-Zero documents 20 on 600 Series refrigeration as a freezer-defrost underheat condition with missing feedback at defrost start.
21Error code
Sub-Zero documents 21 on 600 Series refrigeration as a defrost-overheat warning whose owner path depends on actual compartment temperature.
24Error code
Sub-Zero documents 24 on 600 Series refrigeration as a defrost-underheat warning with an owner response only near normal temperatures.