SubZero Refrigerator Freezer Error Code 22 – How to fix? by KatyApplianceRepair.com 

Sub-Zero error code EC 22 indicates
a wiring or defrost issue. Below is a quick reference
and troubleshooting guide for this code.

Quick Reference

Error Code	Meaning	Severity
EC 22	No voltage feedback through Gray/White wire at defrost start — wiring or defrost fault	Medium

Cause & Solution

Cause	What to Check	Fix
Broken or disconnected Gray/White defrost wire	Trace the Gray/White wire from the defrost heater to the control board	Repair or replace damaged wiring
Faulty defrost heater or control board relay	Test heater resistance and board relay output	Replace the defective component — technician recommended