SubZero Refrigerator Freezer Error Code 55 – How to fix? by KatyApplianceRepair.com 

Sub-Zero error code EC 55 indicates
a faulty thermistor. Below is a quick reference
and troubleshooting guide for this code.

Quick Reference

Error Code	Meaning	Severity
EC 55	Zone/compartment thermistor shorted — temperature sensor failure	Medium

Cause & Solution

Cause	What to Check	Fix
Thermistor shorted internally	Measure thermistor resistance; compare to model specifications	Replace the thermistor
Wiring damage between thermistor and control board	Inspect wiring for pinches, cuts, or corrosion	Repair or replace the wiring harness