Samsung error code E121
What it means
Indoor room temperature sensor fault.
Possible causes
Room thermistor short or open Loose or corroded sensor connector on indoor PCB Damaged analogue input on PCB
Suggested fix
Measure sensor resistance against Samsung specifications and verify connector integrity; replace the thermistor or the indoor PCB input stage as indicated by the resistance test results.
Safety first. Isolate the power supply before inspecting any unit. Refrigerant-circuit
and electrical repairs must be carried out by a qualified, registered technician.
Other Samsung codes
- E101 — Indoor unit communication error.
- E102 — Communication error between indoor and outdoor units.
- E108 — Duplicate device address error on the communication network.
- E122 — Indoor EVAP IN temperature sensor error (short or open).
- E123 — Indoor EVAP OUT temperature sensor error (short or open).
- E154 — Indoor fan motor or fan system error.
- E163 — EEPROM option data error on the indoor PCB.
- E554 — Gas leak detected by the outdoor unit protection logic.
- E556 — Indoor and outdoor unit capacity mismatch error.