Samsung Mini Split C123 Error Code

Updated 2026-08-30 · review status: manual-verified · reviewed by MiniSplitDecoder Editorial Team Last verified: 2026-08-30

Check your model first

  • E-prefix series (per Be Cool / Samsung E-C cross-reference)

Match the model on your equipment label to the linked manufacturer documentation. The same code can mean different things across model families.

Quick answer

C123 on a Samsung mini split is a motion/sensor error. Reset once at the breaker; if C123 returns, sensor or board diagnosis is a technician job.

Severity: medium · DIY difficulty: easy

Safety

Stop at the breaker power-cycle and any plug-accessible checks (filters, remote settings, visible wiring). The outdoor unit's capacitor holds a lethal charge and the refrigerant circuit is both pressurized and (on R-32 units) flammable — opening panels or servicing the sealed system is licensed-technician work (EPA 608).

What C123 means

C123 means the motion sensor (or assigned sensor) reading cannot be trusted, so the unit stops or limits operation. Samsung WindFree Premium service manual: Motion sensor error.

Code meaning varies by series

  • E-prefix series (per Be Cool / Samsung E-C cross-reference): E123 = Evaporator-out (indoor coil out) temperature sensor open/short - first letter may differ by model; verify against your model's table before ordering parts

First checks before service

This page currently documents the safe reset triage. If the code returns, use the linked source manual or a qualified technician for code-specific diagnosis.

  1. 1. One-time fault event (power disturbance or transient sensor reading) common DIY

    Check: Power-cycle at the breaker/disconnect (or unplug for CPAP), restore, and run the system while watching for the code.

    Fix: If the code does not return after a full run cycle, the fault was transient — monitor, no repair needed.

  2. 2. Fault persists after a clean reset occasional pro only

    Check: If the code returns immediately or every session, note the conditions (startup, heating, after rain).

    Fix: A persisting code points at the component the manual assigns to this code — that repair is technician territory.

Related codes

Cross-references for the same fault family, by brand:

Samsung C122 · Samsung C121 · Samsung C140 · Samsung C142

Commonly searched as: "samsung c123" · "samsung error code c123" · "samsung air conditioner c123"

Sources

Related Mini Split guides

Mini-Split Communication Error: DIY Checks · Mini-Split Flashing Light Decoder: Blink Patterns · Mini-Split Maintenance Checklist: Seasonal DIY Tasks · Mini-Split Not Cooling: Ranked Causes and DIY Checks