Sub-Zero error code · 20 2 01
Sub-Zero Code 20 2 01: Defrost Bi-Metal Stuck Closed
Sub-Zero code 20 2 01 means the defrost bi-metal is stuck closed. Verify it is closed above 70F, then replace the defrost bi-metal thermostat if faulty.
Sub-Zero code 20 2 01 means the defrost bi-metal (defrost termination thermostat) is stuck closed. Verify the bi-metal is closed above 70F (21C), and replace the defrost bi-metal if it is faulty.
What 20 2 01 indicates
The defrost bi-metal senses evaporator coil temperature and is expected to be closed at warm temperatures and open when cold. With this fault the board sees the bi-metal closed when it should have opened, indicating it is stuck closed. Sub-Zero directs verifying the bi-metal is closed above 70F and replacing it if necessary.
Likely causes
- Defrost bi-metal contacts welded or stuck closed
- Aged or contaminated bi-metal that will not open at temperature
- Wiring short across the bi-metal terminals
- Bi-metal mounted poorly so it reads incorrect coil temperature
What causes 20 2 01
Bi-metal contacts can weld or fail to open after repeated defrost cycles and thermal stress. Contact pitting, aging, and contamination keep the switch closed past its set point. A wiring short across the bi-metal can also mimic a permanently closed circuit.
Symptoms you may notice
- SERVICE light on
- Defrost heater may run longer than intended, raising compartment temperature
- Inconsistent freezer or refrigerator temperatures
- Possible odors or slight warming during prolonged defrost
- Fault code 20 2 01 stored or shown in service mode
Parts typically replaced for 20 2 01
- Defrost bi-metal (defrost termination thermostat) — Replace if it does not behave as a closed switch above 70F (21C) and open when cold, or is otherwise faulty
Owner-safe checks for 20 2 01
- Power the unit off at the breaker for two minutes, then restore power to see if the code clears
- Note any unusual warming or temperature swings in the freezer
- Confirm doors seal fully and the unit has normal airflow clearance
- Record the exact code for the technician
When to call a technician
Confirming the bi-metal opens and closes at the correct temperatures and replacing it requires ohm-testing and access to the evaporator area, which a technician should handle.
Frequently asked
Sub-Zero 20 2 01: people also ask
What does Sub-Zero code 20 2 01 mean?
Code 20 2 01 means the defrost bi-metal, the defrost termination thermostat, is stuck closed. The switch should be closed when the evaporator coil is warm and open once it cools, but here the board sees it still closed when it should have opened. With the SERVICE light on, the board flags the bi-metal as stuck closed.
How does a technician verify the 20 2 01 fault?
The defrost bi-metal should read closed above 70F (21C) and open when cold. A technician ohm-tests the switch across that temperature range after accessing the evaporator; if it stays closed past its set point or a wiring short bridges the terminals, the bi-metal is replaced. A short across the bi-metal can mimic a permanently closed switch, so that is checked too.
How is 20 2 01 different from 20 2 00?
They are mirror-image failures of the same bi-metal. 20 2 01 is stuck closed, confirmed by remaining closed above 70F, while 20 2 00 is stuck open, confirmed by reading open below 40F. The stuck-closed case in 20 2 01 can let the defrost heater run longer than intended, raising compartment temperature, rather than leaving the coil iced.
Is there anything I can safely do about 20 2 01 myself?
Owner-safe steps are limited to a two-minute breaker power cycle to see if the code clears, noting any unusual warming or temperature swings in the freezer, and confirming the doors seal and airflow clearance is normal. Confirming the switch behavior and replacing it needs ohm-testing and evaporator access, so leave the repair to a technician.
Is it safe to keep using the refrigerator with 20 2 01?
This is a medium-urgency fault. The unit keeps running, but a bi-metal stuck closed can let the defrost heater run too long, causing inconsistent freezer and refrigerator temperatures and possible slight warming or odors during prolonged defrost. It will keep cooling short term, but schedule service to avoid temperature swings.
What part is replaced for 20 2 01 and what is the cost?
The part is the defrost bi-metal (defrost termination thermostat), replaced if it does not act as a closed switch above 70F and open when cold, or is otherwise faulty. Our diagnostic is a flat $89 to verify the switch behavior, the repair carries a 365-day warranty, and you can call (650) 668-1554 to book.
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