Sub-Zero error code · 20 2 05
Sub-Zero Code 20 2 05: Mis-Wired Defrost Bi-Metal
Sub-Zero code 20 2 05 means the defrost bi-metal responded inappropriately at normal defrost temps. Check the bi-metal wiring and mounting; correct or replace.
Sub-Zero code 20 2 05 means the defrost bi-metal gave an inappropriate response during defrost even though temperatures were normal, pointing to a wiring or mounting problem. Check the bi-metal wiring and mounting, and correct or replace as needed.
What 20 2 05 indicates
During defrost the board saw normal evaporator temperatures but the bi-metal switch did not respond the way it should, which indicates the bi-metal is mis-wired or not mounted correctly rather than a temperature problem. Because temperatures were in range, this is logged without the SERVICE light. Sub-Zero directs checking the wiring and the bi-metal mounting.
Symptoms you may notice
- No SERVICE light, but fault code 20 2 05 stored in service mode
- Defrost cycle completes but logs an inconsistency
- Intermittent or borderline frost behavior on the evaporator
- Symptom often follows recent service or a disturbed wiring harness
- Otherwise normal cooling temperatures
What causes 20 2 05
Incorrect routing or swapped connections at the bi-metal, a connector on the wrong terminal, or a switch that lost firm thermal contact with the evaporator all cause the response to disagree with the measured temperature. This often appears after a prior repair, a disturbed harness, or a loosened mounting clip.
Likely causes
- Bi-metal wiring routed or connected incorrectly
- Connector on the wrong terminal or loose at the bi-metal
- Bi-metal not mounted with proper thermal contact to the evaporator
- Pinched or chafed harness altering the bi-metal signal
Parts typically replaced for 20 2 05
- Defrost bi-metal (defrost termination thermostat) — Replace only if the switch or its mount is damaged; first correct the wiring and remount per spec
- Bi-metal wiring or connector — Repair or reseat connections found mis-wired or loose during inspection
Owner-safe checks for 20 2 05
- Power the unit off at the breaker for two minutes, then restore power to see if the code clears
- Note whether the code appeared after a recent repair or service visit
- Confirm cooling temperatures still seem normal in both compartments
- Record the exact code for the technician
When to call a technician
Diagnosing mis-wiring and verifying correct bi-metal mounting requires accessing the evaporator harness and tracing connections, which a technician should perform.
Frequently asked
Sub-Zero 20 2 05: people also ask
What does Sub-Zero code 20 2 05 mean?
Code 20 2 05 means the defrost bi-metal gave an inappropriate response during the defrost cycle even though evaporator temperatures were normal. Because the temperatures were in range, the board reads this as a wiring or mounting problem with the bi-metal rather than an actual temperature fault, which is why there is no SERVICE light, just a stored code.
Why did 20 2 05 appear right after a service visit?
This code very often follows recent service or a disturbed harness. Leads can be swapped, a connector can land on the wrong terminal, or the mounting clip can be loosened so the bi-metal loses firm thermal contact with the evaporator. Any of these makes the switch response disagree with the measured coil temperature and triggers 20 2 05.
How is 20 2 05 different from 20 2 06?
Both are mis-wired or misplaced defrost bi-metal faults, but 20 2 05 logs quietly with normal temperatures and no SERVICE light, while 20 2 06 fires with the SERVICE light on because evaporator temperatures actually climbed too high during defrost. In short, 20 2 05 is the low-severity, in-range version of the same wiring or mounting problem.
Can I fix 20 2 05 myself?
Owner-safe checks are a two-minute breaker power cycle to see if the code clears, noting whether it appeared after a recent repair, and confirming cooling still seems normal in both compartments. Correcting mis-wiring or remounting the bi-metal means accessing the evaporator harness and tracing connections, which a technician should do.
Is it urgent to address 20 2 05?
It is a low-severity fault. Cooling temperatures are usually still normal and the defrost cycle completes, just with a logged inconsistency and possibly borderline frost behavior. It is not an emergency, but correcting the wiring or mounting prevents it from progressing into a worse defrost fault later.
What gets fixed for 20 2 05 and what does it cost?
The technician first corrects the bi-metal wiring and remounts it to spec, repairing or reseating any mis-wired or loose connector; the defrost bi-metal itself is replaced only if the switch or its mount is damaged. We charge a flat $89 diagnostic, back the work with a 365-day warranty, and can be reached at (650) 668-1554.
Subzero Repair · Open 24/7 · 365-day warranty
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