Sub-Zero 600 and 700 Series Code 05: Refrigerator cabinet sensor reading lost

What 05 means

On legacy 600 Series built-in units like the 650/F, and 700 Series integrated models such as the 736TCI, code 05 means the refrigerator cabinet thermistor has been open or shorted for 10 seconds or more, or is giving erratic readings. That sensor tells the control how cold the fresh-food section is. Without a believable reading, temperatures in the fresh-food section can drift too warm or too cold.

Common causes of 05

Refrigerator cabinet thermistor open or shorted
Damaged wiring to the cabinet thermistor
Loose connection at the control board

✓ One safe check you can try

1. Note code 05. 2. Check the fresh-food temperature with a thermometer. 3. Switch power off at the panel; after two minutes, switch it on. 4. Keep food from pressing against the back wall where the sensor sits. 5. Schedule service should the code return.

! Why to stop there

The thermistor and its wiring sit behind interior panels.
Testing resistance requires a meter and the right reference values.
Erratic readings can come from wiring, not just the sensor.

Opening a panel yourself does not automatically cancel a manufacturer warranty, but it can cause accidental damage, and some manufacturers set their own service conditions. Check your warranty terms, or ask us, before deciding.

→Same appliance

Other Refrigerator codes

deSub-Zero 600 and 700 Series Display de: Diagnostics enabled 23Sub-Zero 600, 700 and 648PRO Code 23: Defrost overheat with no feedback 50Sub-Zero 600 and 700 Series Code 50: Refrigerator compressor running too long 41Sub-Zero 648PRO Code 41: Zone compressor or wiring problem 81Sub-Zero 700-2 Code 81: Variable-Speed compressor fails to start 82Sub-Zero 700-2 Code 82: VS compressor controller needs replacement 88Sub-Zero 700TF Code 88: Board and compressor controller not talking 80Sub-Zero 700TF Code 80: No inverter feedback after a board change

0505 questions

What is a thermistor?

It is a small temperature sensor whose resistance changes with cold. Code 05 means the refrigerator cabinet thermistor is open, shorted or jumping around, so the control cannot trust what it reports.

Will the refrigerator still cool?

Often it does, but less accurately, because the control no longer knows the real fresh-food temperature. Use a thermometer and tell us if it goes above 40°F.

How is it fixed?

We measure the sensor and its wiring, then replace whichever tested bad. You receive a written price before work, and our labor carries a 30-day warranty.