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121

Error 121 - Indoor temperature sensor error

Samsung · Home Automation

What does 121 mean?

The indoor unit's temperature sensor is either short-circuited or open-circuited, meaning it cannot accurately read room temperature.

Common Causes

  • Faulty temperature sensor
  • Damaged sensor wiring
  • Loose sensor connection to the control board

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Inspect the indoor temperature sensor and its wiring for any visible damage.

  2. 2

    Check that the sensor is securely connected to the indoor unit's control board.

  3. 3

    If the sensor appears damaged or the error continues, replacement may be necessary by a technician.

Browse all codes in this manual (60)
Verified technical data. Last updated: April 2026

Related Faults

101Error 101 - Indoor unit communication error102Error 102 - Indoor/Outdoor unit communication error108Error 108 - Repeated address setting
Source: Samsung Home Automation
Open Manual (Page 22)Search more codes in this manual