ERROR CODE EXPLAINED
Sub Zero 600 Series Refrigerator
Sub Zero 600 Series Refrigerator EC 20 Error Code
What it means
Sub-Zero identifies 600 Series error 20 as defrost underheat with no voltage feedback through the gray/white wire at defrost start, and its troubleshooting guidance identifies an issue with the freezer defrost terminator.
Try this first
- Sub-Zero provides no customer troubleshooting procedure for error 20.
- If the issue remains, contact Factory Certified Service to schedule a repair appointment.
Can I keep using it?⚠ Sub-Zero identifies 600 Series error 20 as defrost underheat with no voltage feedback through the gray/white wire at defrost start, and its troubleshooting guidance identifies an issue with the freezer defrost terminator.
Repair usually required?⚠ Follow only the manufacturer-backed checks listed below before further repair diagnosis.
If the error keeps returning
Use the linked official Sub-Zero, Wolf, and Cove support article and contact Factory Certified Service if the issue remains.
Official source
Troubleshooting information verified against manufacturer support documentation.
View manufacturer support page →Safety note:ApplianceSignal provides general troubleshooting information. Always follow the appliance manufacturer's safety instructions and disconnect power when required.